Does stackoverflow.com use dependency injection?
Which tools and technologies are used to build the Stack Exchange Network?
I wanted to know if there is difference in terms of charging the battery when a MacBook Pro 16" is connected to two monitors via USB-C, both with Power Delivery capability.   In this specific case I am talking about the LG 27UK850-W monitors. The MacBook Pro 16" will be connected via USB-C to both of them and use them as external monitors. Since both can charge it as well, will the MacBook Pro  charge faster while being connected to both or will just one monitor be able to deliver the charge at a time? How is ** implemented in Python? I'm wondering where I find the source to show how the operator ** is implemented in Python.  Can someone point me in the right direction? Iterating each character in a string using Python In C++, I can iterate over an std::string like this:  std::string str = "Hello World!";  for (int i = 0; i &lt; str.length(); ++i) {     std::cout &lt;&lt; str[i] &lt;&lt; std::endl; }   How do I iterate over a string in Python? Recreate plot when data file changes Is it possible to use the TikZ/external library and have pgfplots recreate a figure when a data file that is plotted changes? Say I have something like the following:  file.tex:  \documentclass{article}  \usepackage{tikz,pgfplots} \usetikzlibrary{external} \pgfplotsset{compat=newest} \tikzexternalize \newcommand{\figFilename}{}  \begin{document}   \begin{figure}[t]     \centering     \renewcommand{\figFilename}{thePlot}     \tikzpicturedependsonfile{\figFilename.tikz}     \tikzsetnextfilename{\figFilename}     \input{\figFilename.tikz}     \caption{The caption.}   \end{figure} \end{document}   thePlot.tikz:  \begin{tikzpicture}   \begin{axis}[     xlabel={$x$},     ylabel={$y$},]     \addplot+[only marks,mark=x]       table[x=x,y=y] {data.dat};   \end{axis} \end{tikzpicture}%   data.dat:  x y 0 20.44 1 20.06 2 19.76 3 19.54 4 19.40 5 19.34   If I change thePlot.tikz, the external library will detect that the figure is no longer up-to-date and recreate it. Is it possible to have the same effect when any of the plotted data files changes as well? I tried something along the lines of \tikzpicturedependsonfile{data.dat}, and it doesn't work. That wouldn't be an ideal solution anyway, as most times I use many data files in each plot and listing all dependent files manually would be more pain than gain.  So is there an easy, automated way for the external library to check all data files included in a tikzpicture and recreate the plot if at least one of them has changed? File names for JSP include directive to avoid compilation of them Slope layer with false results in QGIS? After the DEM creation, I wanted to create slope layer.   However, the result has not satisfied me. I don't think the slope map is correct. Have you ever encountered false calculated terrain map?  This is the DEM:    And this is the slope layer. What are homologous chromosomes? Triggered send status queued, need to get an alert Integral $\int^{ \pi /2}_{0} \ln (\sin x)\ dx$ $$\int^{ \pi /2}_{0} \ln (\sin x)\  dx$$  The answer is $- \frac{\pi}{2} \ln 2$.  I have changed it into $$\frac{1}{2} \int^{1}_{0} t d \ln t^{2}$$  But I didn't get the answer with it. Different batteries connected in parallel If we have 2 batteries one of emf x and the other is of emf y and we connect them in series we get an effective emf of x+y.  But what if we connect them in parallel, how to calculate the emf now? (Disclaimer: I've read the  and I do understand that this is bordering on off-topic since it's about consumer devices. However I hope that I've managed to make enough on-topic by asking about why it is the way it is, and what is the explanation from an electromagnetic point of view - in other words, what laws of electricity and what practical considerations have gone into these decisions).  I recently bought a power tool and in its manual I found a few peculiar safety rules. I cannot see why they would be there, although reading up more it seems that they are commonplace. My understanding of electricity is limited (just about enough to be dangerous), so I'm hoping to expand it. :)  The rules are:   Don't use an extension cord longer than 25m. Considering this is an outdoors tool, this limitation is severely restrictive. The best explanation I've seen is that longer cables would simply have too high of a resistance and the tool wouldn't be able to operate at full power. But this argument doesn't convince me. The tool is rated at 2.4kW, and it's meant to be used with 220V AC power source, which means it uses about 11 amps of current. All the extension cords I've ever come across have at least 16A limitation, so there is quite a reserve still. In addition, the power has to travel much, much further to get to my house, and even after the meter it still takes probably close to those same 25m to get to the power outlet. Why only 25m after the outlet? The resistance of the cables isn't that big, is it? Don't daisy-chain extension cords. I suspect this is a variation of the above - don't exceed 25m; every connection adds additional contact resistance; water in the outdoors connections can be a problem - in general, it just adds risk. However, apart from the water in the contacts, the rest seems to me to be practically negligible. Is there really a significant contact resistance? Assuming that the extension cords are in a good shape. Make sure that the power cord is entirely unrolled. This is another odd one. My suspicion is that it has to do with inductive resistance. But is it really that strong? Wherever I've seen people actually wanting to create an electromagnet, it's pretty much hard work. You need a lot of neat, tightly-wound loops of wire. An extension cord has a lot of insulator around it, spacing the wires pretty far apart, and the loops are very chaotic. In addition, if that was a problem, why do  exist? They're used especially when you need a very long extension cord, and you don't need to unroll them completely every time you want to use them. Solved: OK, I was off the mark. The correct answer (also a ) has to do with the wire heating up from being used close to its limits. When coiled together, the temperature can go pretty high and melt the cables. Not fun. Find lost device without Gmail account configured and without SIM card I recently misplaced a phone that did not have gmail account configured and did not have a SIM card in it either. Is there any way I can track it ?   All of the tracking apps either require sending an SMS (needs SIM card) or OTA install(needs Gmail account).   I do have the IMEI number of the phone. I want to find a formula for the sum of this series using its general term. How to do it?  Series $$ S_n = \underbrace{1/3 + 2/21 + 3/91 + 4/273 + \cdots}_{n \text{ terms}} $$  General Term  $$ S_n = \sum_{i=1}^{n} \frac{i}{i^4+i^2+1} $$ What's is the origin of Orbital Angular Momentum of electrons in atoms? Consider the Hydrogen 1s electron. We know that, in the quantum picture, the electron isn't orbiting or rotating at all, rather we simply state that the electron is spread over the entire space with the probability of finding it being maximum a radial distance $R$ (=Bohr radius) away from the nucleus. This helps explain why the electron does not radiate EM radiation while in the atom.  But, with this understanding, I do not understand the source of the orbital angular momentum. Is it intrinsic like the spin? Convert from LyX/Latex to wordpress post I have some documents in LyX/Latex and I want them as a wordpress post. I have tried converting latex to HTML (with latex2html) and afterwards, pasting that code in the wordpress editor but everything looks ugly. Do you know a better approach? Why didn't Doc remember Marty's outfit? In Back to the Future 3, Doc (from 1955) sends Marty back in time wearing a cowboy outfit.  But then, Doc (from 1885) doesn't remember that it was him who offered this outfit to Marty.   Does this mean there are two different Docs (from differing timelines) or is it the same Doc but he somehow forgot the outfit. Magnetic field lines When I searched the net about magnetic field lines,  told something about contour lines and that magnetic materials placed along a magnetic field has some specific loci, which i did not understand. Can someone explain it to me in details.  Also how do we know that tangent to a magnetic field line gives the direction of magnetic field? I am very confused. Get TEXT value of a CLOB OID in Postgresql When and why is the [featured] tag removed by the Community user? I've found that the Meta (moderator only) tag  is automatically  by the  user. So, I want to know when and why is the tag  is removed by this user?  Is there any mechanism for this removal or is there simply a specified time period after which the  is automatically removed by the Community user? Consider a rocket in deep space with no external forces. Using the formula for linear kinetic energy $$\text{KE} = mv^2/2$$ we find that adding $100\ \text{m/s}$ while initially travelling at $1000\ \text{m/s}$ will add a great deal more energy to the ship than adding $100 \ \text{m/s}$ while initially at rest: $$(1100^2 - 1000^2) \frac{m}{2} \gg (100^2) \frac{m}{2}.$$ In both cases, the $\Delta v$ is the same, and is dependent on the mass of fuel used, hence the same mass and number of molecules is used in the combustion process to obtain this $\Delta v$. So I'd wager the same quantity of chemical energy is converted to kinetic energy, yet I'm left with this seemingly unexplained $200,000\ \text{J/kg}$ more energy, and I'm clueless as to where it could have come from.