After finding , I thought about inspecting Community's ♦ profiles. What did I notice? Community ♦ have more than 1 rep on some meta sites.    - 5 rep  - 3 rep  - 3 rep  - 3 rep   Why is it?
Until recently  had one single reputation point, you can see it in this old screenshot:    Now it has over 2K reputation all of a sudden.. what has caused this? Has it affected "real" members as well?
SUID-bit not working for executables within /tmp directory Printing the value of getuid() and geteuid() from an executable with SUID-bit (chmod +s) turned-on, seems to result with the original caller ID instead of the owner id if the executable is located within the /tmp directory.  When compiling the exact same code to home directory (and executing chmod +s), this seems to work as expected.  I've searched a lot and could not find any reference to such behavior.  Does anybody know why is this happening?  this source is simple as that:  #include &lt;stdio.h&gt; #include &lt;stdlib.h&gt; #include &lt;sys/types.h&gt; #include &lt;unistd.h&gt;  int main(){     printf("%d\n%d\n", getuid(), geteuid());     return 0; } SSL_read failing with SSL_ERROR_SYSCALL error Astrophotography picture with too much noise. How do I correct this in postprocessing? This is the Milky Way above Kakadu National Park, Australia, and my first try at astrophotography.    Thirty second exposure, f/4.0 at 17mm with ISO 12800 (!!) which in hindsight probably was way too high and resulted in a lot of noise. I also used Picasa to increase contrast, but I probably went a bit overboard there as well.  , I am looking for input on how to better postprocess this picture to reduce noise. What are the differences between "to talk" and "to speak"? What is the ideal way to handle data pins D+ and D- on a USB power adapter to be compatible with fast charging on devices? Escape velocity from a rotating black hole Under Newton, the escape velocity is  $$v_{esc} = \rm c \ \sqrt{r_s/r}$$  where $\rm r_s=2 \ GM/c^2$. In the nonrotating relativistic case (the Schwarzschild case) the radial escape velocity is the same:  $$v^{\parallel}_{esc} = \rm c \ \sqrt{r_s/r}$$  which is the speed of light, $v={\rm c}$, at the event horizon at $\rm r=r_s$. Since the photon sphere, where an object with $v={\rm c}$ would not escape, but be captured into orbit, is at $r=3 \ {\rm GM/c^2}$, the transverse escape velocity is  $$v^{\perp}_{esc} = \rm c \ \sqrt{r_s/r}\div \sqrt{1-r_s/r}$$  and for the observed (shapiro delayed) velocity ${\rm v}$ the transformation is  $${\rm v}^{\perp}=v^{\perp} \ \sqrt{\rm 1-r_s/r} \ , \ \ {\rm v}^{\parallel}=v^{\parallel} \ (\rm 1-r_s/r)$$  so the observed angular motion is the same as with Newton, yet locally higher, while the observed radial motion is slowed down because of the radial length contraction and time dilation.  But what about the Kerr case where the rotation is significant and the event horizon is at $\rm r=(1+\sqrt{1-a^2}) \ {\rm GM/c^2}$ instead of $\rm r=r_s$?  A testparticle which is locally at rest and therefore corotating with the angular velocity of the frame dragging  $${\Omega = \rm d \phi/ {\rm d t} = {\rm 2 \ a \ r/((a^2+r^2)^2-a^2 (a^2+(r-2) \ r) \sin ^2(\theta ))}}$$  should experience the time dilation factor  $$\rm \dot t = {\rm d t}/ {\rm d}\tau = \sqrt{{\rm ((a^2+(r-2) \ r) (a^2 \cos ^2(\theta )+r^2))/((a^2+r^2)^2-a^2 (a^2+(r-2) \ r) \sin ^2(\theta ))}}$$  relatively to the far away observer, so multiplying $\Omega$ with $\rm \dot t$ should give the local frame dragging angular velocity, which, multiplied with the $\rm \sqrt{x^2+y^2}$ value of the Boyer-Lindquist to cartesian transformation should give the transverse velocity - this is slightly below $\rm c$ for a maximaly rotating black hole (with $\rm a = 1$ - at the edge of the outer equatorial ergosphere where $\rm r=1$ and $\rm R=\sqrt{r^2+a^2}$).  But how do I find the radial and total escape velocity, and what are the rules to convert the shapiro-delayed coordinate velocities $\rm d r/d t \ , \ d \phi/d t \ , d \theta/d t$ to the local 3-velocity components $v^{\parallel}$ and $v^{\perp}$ of a test particle (local meaning relatively to a frame dragged probe with contant $\rm r$)? The radial length contraction seems a bit different than in the Schwarzschild-case, where it is the same as the gravitational time dilation factor... Here is what it looks like in Blender Render (Not Cycles).   This is how I set it up.   Basically, I'm trying to export it, but it's not including the &quot;Freestyle&quot; lines. When I open up the .dae file in Finder, it looks like this:   What is wrong here? I want it to be exported (COLLIDA .dae) with the black outline. I'm seeming to think that maybe the &quot;Freestyle&quot; is only for the Blender Render. Am I right? How would I go about getting the black outline included in my exported model? Is it an export setting I have to tick? Thanks for any helpful answers. I know that there's a difference between relativistic and rest mass. Relativistic mass is "acquired" when an object is moving at speeds comparable to the speed of light. Rest mass is the inherent mass that something has regardless of the speed its moving at.  When fusion happens, a certain percentage of the rest mass of two hydrogen atoms is converted into energy. I understand that $E = m_{rest}c^2$.   How does the rest mass of an object turn into energy? Does this involve particle physics? Doesn't this suggest that rest mass can be viewed as some sort of potential energy? It seems to me that it's a sort of locked energy that has to undergo a certain process to expel its energy to surrounding particles.  Also, Why does only a small percentage of rest mass turn into energy? Why not all of it. What dictates how much rest mass gets converted into energy? I would like to visit Iran as a tourist but I'd also like to visit the USA some time after. I know the relations between the two countries are bad.   Is it likely that I'm not allowed to enter the USA after having been to Iran?   If it matters, I've never been to either of those countries. I'm a Swiss citizen, an atheist from a Christian background. I replaced a buggy Windows Vista installation with Ubuntu. All works fine except that the main HD where I had all my files are now inaccessible. Here is the error message I get:   Error mounting: mount exited with exit code 13: ntfs_attr_pread_i: ntfs_pread failed: Input/output error Failed to read NTFS $Bitmap: Input/output error NTFS is either inconsistent, or there is a hardware fault, or it's a SoftRAID/FakeRAID hardware. In the first case run chkdsk /f on Windows then reboot into Windows twice. The usage of the /f parameter is very important! If the device is a SoftRAID/FakeRAID then first activate it and mount a different device under the /dev/mapper/ directory, (e.g. /dev/mapper/nvidia_eahaabcc1). Please see the 'dmraid' documentation for more details   Is it necessarily a hardware problem? If not, is there a way to repair the HD from Ubuntu? Application is "Ready to Sale" but not reflected on iTunes Store Why did my windshield freeze instantaneously? Minecraft LAN "java.net.ConnectException: Connection refused: no further information:" I am trying to play a map on LAN. But every time I try to log on, I get:     java.net.ConnectException: Connection refused: no further information:   This used to work, but for some reason has stopped all of a sudden. I looked it up online, and everything I found said the firewall just wasn't allowing Java through. I followed tutorials to allow Java through the firewall, but even then it won't work. I know for a fact that I'm putting the IP in correctly, and everything seems to be correct, but yet I still get the same error message.  If it helps any, I'm using MC version 1.8.9 (the map requires it), and I don't have any mods. So I am using cryptopp to encrypt a file in a project and I am using AES-GCM. I have a 256bit key and a 128bit ivec and a 128bit tag that I use to encrypt files.  However, I want to know where the authentication tag is stored? I notice if I specify a tag size of 0 then the encrypted file size is the same number of bytes as the original file.  Is the authentication tag simply appended to the end of the file? If $q$ is coprime to $a$ then $a\mid nq-1,\,$ so $q$ is invertible mod $a$ I think the following is true:  If $q$ is coprime to $a$ then $a\mid (nq-1)$ for some $n\in\mathbb Z$.  I have started to first reducing $n\in\mathbb Z$ to $n\in\{1,\ldots,a-1\}$ and then considering all the cases $q = ka + j$ for $j=1,2,3,\ldots,a-1$. I stopped at $j=3$ and found that this is kinda messy. Does anyone have an elegant proof for this (maybe using some results from number theory)?  [Note: question has been generalized from prime $q\nmid a$ to $\,q$ coprime to $a$] Last year I hired someone to do some work for our website but accidentally lost the PSD files since then. It's a fairly basic concept but I am fairly inexperienced with using masks.  How can I create the black circular gradient area as shown in this image below? I need to get as close as possible where it matches existing images on the site, why I am hoping its not too hard.  Thank you! Is a URI (specifically an HTTP URL) allowed to contain one or more space characters? If a URL must be encoded, is + just a commonly followed convention, or a legitimate alternative?    In particular, can someone point to an RFC that indicates that a URL with a space must be encoded?  Motivation for question: While beta-testing a web site, I noted that some URLs were constructed with spaces in them. Firefox seemed to do the right thing, which surprised me! But I wanted to be able to point the developers to an RFC so that they would feel the need to fix those URLs. I have been thinking on and off about a problem for some time now. It is inspired by an exam problem which I solved but I wanted to find an alternative solution. The object was to prove that some sequence of functions converges weakly to zero in $L^2$.   I managed to show (with some help) that the limit $f$ (of a subsequence) satisfies $\int_0^x f \ dm=0$ for all $x&gt;0 $. From this I want to conclude that $f=0$ a.e. I can do this with the fundamental theorem of calculus in its Lebesgue version but there ought to be a more elementary proof.  Can someone here help me out? Children’s books, one in space setting, the other in a jungle When I was little I remember getting these two books from the library.  Both books were paperback and flimsy.  The pages were wide.  Each book had full page illustrations with puzzles and mazes in them, but it was like you were immersed in this setting completely.  They were also like choose-your-own adventure books, but only in the way that you go through the book in a different order based on your results in the puzzles/games.    For example, there is a bridge to cross, or you can take this path.  If you choose to cross the bridge you go to page x.  On page x you have to pretend to cross the bridge but some planks are broken.  You can't skip more than a certain number of planks, but you also cannot "step" on a broken plank.  One book was in a jungle setting with rope bridges, alligators, quick sand, etc. The other was in space, with all kinds of aliens and weird stuff.  I have faint memories of these books but I REALLY want to track them down because I remember loving them. When I compile the Python code below, I get      IndentationError: unindent does not match any outer indentation level     import sys  def Factorial(n): # Return factorial     result = 1     for i in range (1,n):         result = result * i     print "factorial is ",result     return result   Why?