I have a mixture of knob-and-tube and NM-B. If I'm extending from knob and tube, but I have a (different) an NM-B circuit nearby, is it technically allowable to ground via ground wire in the other cable? If not, what is the right way to do it?  (Please don't tell me to replace all the knob and tube -- it's not going to happen.)
I've got a circuit in the basement carrying a handful of outlets.  This circuit has no ground wire.  I want to add a couple of outlets and want them to be grounded.  I may even want gfci outlets on them in the future.  I have no reasonable way of getting a ground wire to the panel but I do have easy access to another circuit that does have a ground wire.  Is it acceptable to borrow or share a ground wire between circuits?  If not, why not?  Both circuits are 20A with 12 AWG wire.
Identification of particles and anti-particles The identification of an electron as a particle and the positron as an antiparticle is a matter of convention. We see lots of electrons around us so they become the normal particle and the rare and unusual positrons become the .  My question is, when you have made the choice of the electron and positron as particle and anti-particle does this automatically identify every other particle (every other fermion?) as normal or anti?  For example the proton is a particle, or rather the quarks inside are. By considering the interactions of an electron with a quark inside a proton can we find something, e.g. a conserved quantity, that naturally identifies that quark as a particle rather than an antiparticle? Or do we also just have to extend our convention so say that a proton is a particle rather than an antiparticle? To complete the family I guess the same question would apply to the neutrinos. Animation Blending Basics Say I have a framework with characters that can run and walk and of course, stand still.  Am I right in thinking that animation blending is the process of smoothly transitioning between these by generating dynamic animations at runtime?  If so, what is the basic theory of how this works, and how would I implement it? Prove this inequality $\sum \cos{A}\ge\frac{1}{4}(3+\sum\cos{(A-B)})$ I have seen many examples of how to render sprites from a spritesheet but I havent grasped why it is the most common way of dealing with sprites in 2d games.  I have started out with 2d sprite rendering in the few demo applications I've made by dealing with each animation frame for any given sprite type as its own texture - and this collection of textures is stored in a dictionary. This seems to work for me, and suits my workflow pretty well, as I tend to make my animations as gif/mng files and then extract the frames to individual pngs.  Is there a noticeable performance advantage to rendering from a single sheet rather than from individual textures? With modern hardware that is capable of drawing millions of polygons to the screen a hundred times a second, does it even matter for my 2d games which just deal with a few dozen 50x100px rectangles?  The implementation details of loading a texture into graphics memory and displaying it in XNA seems pretty abstracted. All I know is that textures are bound to the graphics device when they are loaded, then during the game loop, the textures get rendered in batches. So it's not clear to me whether my choice affects performance.  I suspect that there are some very good reasons most 2d game developers seem to be using them, I just don't understand why. I have CSV data loaded into a multidimensional array. In this way each "row" is a record and each "column" contains the same type of data.  I am using the function below to load my CSV file.  function f_parse_csv($file, $longest, $delimiter) {   $mdarray = array();   $file    = fopen($file, "r");   while ($line = fgetcsv($file, $longest, $delimiter))   {     array_push($mdarray, $line);   }   fclose($file);   return $mdarray; }   I need to be able to specify a column to sort so that it rearranges the rows.  One of the columns contains date information in the format of Y-m-d H:i:s and I would like to be able to sort with the most recent date being the first row. Proposition      Let $\mathcal{P_e}$ be the set of functions $p_e(x) = a_o + a_2x^2 +  \cdots + a_{2n}x^{2n}$, $p_e : \mathbb{R} \to \mathbb{R}$      Show that all $f:[0,1]\to\mathbb{R}$ can be uniformly approximated by   elements in $\mathcal{P_e}$   Attempt:    Since we are talking about polynomials let's try play with Weierstrass Theorem  By definition $\mathcal{P_e}$ is dense in  $C^0([0,1], \mathbb{R})$ , if for every funciton $f \in C^0([0,1], \mathbb{R})$, $\exists p_e \in \mathcal{P_e}$ such that $\forall \epsilon &gt; 0, \forall x \in [0,1], ||p_e-f||&lt; \epsilon$  So we want to show $\|p_e - f\| &lt; \epsilon$  Try something like...since every continuous function is approximated by polynomials i.e. $\forall \epsilon &gt; 0,\ \|f - p\| &lt; \epsilon$, therefore let $p$ be a polynomial, $p = a_0 + a_1x + a_2x^2 + a_3x^3 + \cdots$  $$\|p_e - f\| \leq \|f - p\| + \|p - p_e\|$$  $$\Rightarrow \|p_e - f\| &lt; \epsilon + \|p_o\|,$$ where $p_o$ is an odd polynomial  $$\Rightarrow \|p_e - f\| &lt; \epsilon + \sup_x|a_1+a_3+\cdots+a_{2_n+1}|$$  Stuck.   In any case, $p$ and $p_o$ is poorly defined. What would be the standard approach to prove the proposition? Let $g_n= {2^2}^n +1 $. Prove $g_0 · g_1 · · · g_{n−1} = g_{n} − 2$.    I'm not sure how to start this proof, if it should be done algebraically or if I should try to use a proof by induction. Block apps from accessing the Internet on Android device In Android, is it possible to block apps from accessing the Internet? Many apps will often connect to remote servers in the background, including Google's own apps or system services. Over time this can eat away at a user's data limit set by a mobile carrier. Does Android allow an app to act as a firewall whereby the user can select which apps have access to the Internet? Or does the device have to be rooted to have that ability? Proving the so-called "Well Ordering Principle" Is there a way to enter the default keyring password using the command line?   For instance:  You have a remote setup of Ubuntu 10.10 thats set to auto login. You don't want to remove  the keyring password.  All right the system boots up and logs in automatically, then asks for the keyring password now at this point you can create ssh connections but you can't remote desktop.   What can you do to enter the keyring password at this point?  Also, to better clarify, this is from a remote connection using the command line. I need to know what the original account was for my Clash of Clans is so I may transfer to another device. Any suggestions? I have tried multiple times trying to find through my emails with no luck. Can Game Center email a list of my CoC account? 'Some index files failed to download' while updating How to get scroll position from GridView? No file output after rendering? I usually am able to render successfully to the c:\tmp folder, but when I came into work today, I rendered out the image on my work laptop, and everything seems to work, but I'm not getting an output to the tmp directory.  Does anyone know how to make this work? The  was observed, giving us the frequency and amplitude of the event. Because LIGO has two detectors a  could be derived.  But how do these three factors allow for the mass of the black holes and their distance to be calculcated? If the wave strengths are in a square relationship to distance, then couldn't there be an infinite number of other masses and distances which would give the same signals? Start modal operator from a click in panel I want to start a modal operator by clicking a button in a panel in the properties region. It should then stop when I click somewhere in the 3D viewport. I want to execute some code when I start and finish the operator (see the code below). I tried modifiyng the modal operator template with an execute method to start the modal operator. But the now the context.space_data.type is always &quot;PROPERTIES&quot; because that's where the panel is located, I guess. Is this a bad way of doing what I want? class MY_OPERATOR_OT_click_on_3dview(bpy.types.Operator):          bl_idname = &quot;mesh.click_on_3dview&quot;     bl_label = &quot;Click on 3D&quot;      def modal(self, context, event):                  if context.space_data.type != 'VIEW_3D':             return {'PASS_THROUGH'}                  if event.type in {'MIDDLEMOUSE', 'WHEELUPMOUSE', 'WHEELDOWNMOUSE'}:             # allow navigation             return {'PASS_THROUGH'}         elif event.type == 'LEFTMOUSE':             # DO ALL THE POST-SELECT STUFF             return {'FINISHED'}         elif event.type in {'RIGHTMOUSE', 'ESC'}:             return {'CANCELLED'}          return {'RUNNING_MODAL'}      def execute(self, context):         # DO ALL THE SETUP STUFF           context.window_manager.modal_handler_add(self)              return {'RUNNING_MODAL'}            def cancel(self, context):         print(&quot;CANCEL???&quot;) Lubuntu 16.10: How to make login through greeter without typing password work Significance of the second focus in elliptical orbits Organic yet accurate modeling with the golden spiral Foreword  First off, let me say that I am profoundly amazed at the orderliness in nature. If you haven't heard about the Fibonacci sequence (0, 1, 1, 2, 3, 5, 8, 13, ...), you should check it out.  This mathematical concept of the Fibonacci numbers can be shaped into a set of squares, where the lengths of the sides of the squares follow the Fibonacci sequence:     This is sometimes called a golden ratio. It can be formed into a (golden) spiral. (a.k.a. logarithmic spiral):      Application  I am looking for ways on how to utilize this concept in Blender. Primarily in organic modeling. The golden spiral is found all throughout nature. From flower seed heads, sea shells, and ram horns to hurricanes and spiral galaxies.  My question is: how can I model based off of one or multiple golden spirals? Specifically, I'm interested in modeling a sunflower head like the one in the following image. I'm mostly interested in the point of origin of the individual seeds (not worried about the shape). Does Blender have any features related to this? When should I use "when" and "while"? But you can't find anything while you're crying.   But you can't find anything when you're crying.   I'll tell you about it while Frank saddles the horse.   I'll tell you about it when Frank saddles the horse.     When should I use when, and when while? Are these sentences correct?