Can Aufbau principle be derived/proved with a definite reason?
Aufbau principle in modern quantum theory
What's the difference between "it excites me" and "that excites me"? The brightness of my laptop is reset to max on every restart. I tried the solution provided at  but had no luck.   This command   cat /sys/class/backlight/acpi_video0/max_brightness   Returns   cat: /sys/class/backlight/acpi_video0/max_brightness: No such file or directory   Then I found that I don't have a folder named acpi_video0, but a folder called intel_backlight:    Every time I increase or decrease the brightness using the brightness control keys, the values in brightness and actual_brightness get updated.  Is there any method I could follow to set the brightness to a fixed value on every boot and vary it as and when I need it using the brightness control keys? Community Wiki posts don't change usernames if the user does How can I recover photo files from a memory card with a corrupt filesystem? I know this is not specifically a photography issue but since many of us with prosumer/professional-level DLSRs use Compact Flash cards, it is bound to happen to others as well.  I have a Sandisk 16GB Ultra card that occasionally had the camera reporting inability to access the card. I had to reinsert the card to continue using it. I was able to read the card and transfer the photo files to my computer drive. Today, the same thing happened again, just that nearing the capacity of the card, it failed one last time and the camera was subsequently unable to read it anymore. Despite reinsertion.  My other CF cards never once exhibited this problem, so it's pretty much isolated to this card.  The card is similarly unrecognisable on my computer CF card reader. I think the filesystem is toast, but I suspect the photo files are still intact. I would like to find ways where I can inspect the raw binary data in the card and hopefully recover the photos? XML serialization without null XMLArray What graphics packages are there for creating graphics in LaTeX documents? Let $X, Y$ be an exponentially distributed random variables with parameters $a, b$. Then $X$ has pdf:    $$f_X(x) =\begin{cases} a e^{-a x},&amp; x\geq 0\\ 0,&amp; \text{otherwise}.\end{cases}$$ Suppose $X$ and $Y$ independent. Show that $$\mathbb P(X&gt;Y) = \frac{b}{a+b}.$$   Now I thought the following: $$f(x,y) = f_X(x)\ f_Y(y) = abe^{-ax -by},\qquad\text{for } x,y &gt; 0.$$ And then $$\mathbb P(X&gt;Y) = \int_0^\infty \int_0^x a b e^{-ax -by}\,dydx$$ However, if I solve this (manually or using Wolframalpha), I can't seem to end up with $\frac{b}{a+b}$. Any ideas? What are the limits of the Room of Requirement? How to install .deb file in ubuntu using terminal? I am trying to install Google Chrome,for that I downloaded a google-chrome-stable_current_i386.deb file.  When I try to install using install in terminal   sudo install google-chrome-stable_current_i386.deb  It gives following error.  install: missing destination file operand after ‘google-chrome-stable_current_i386.deb’ Try 'install --help' for more information. How do you generate dynamic (parameterized) unit tests in Python? How to delete duplicate LiDAR points? How can I delete duplicate LiDAR points? I incorrectly read the same las twice and saved as a one file resulting in duplicate XY points.  How should I delete these duplicate points? Why do you need to know who I know on Google? I just created a SE account using my Google account. It said that it needs to "Know who you are on Google" (I guess my connections). As far as I know, SE is not a social network. I can't even follow other people (seeing when they post questions and answers).  What is the reason you need to know my Google connections?  This was on code review. Actually I have an account there, but for some reason it asked me to reconnect. This is the same on MSO; one sees this explained as "This app is requesting permission to associate you with your public Google profile": I'm using an old iBook G4 (PowerPC) running Tiger to serve iTunes to the house. For the past week or so, the mac boots fine, and then sometime during the day starts generating   An unexpected error occurred (error code -50).   errors when iTunes attempts to save its library file.  Checking reveals that the boot drive (main drive, in the laptop) behaves as if it is write-protected - I get the same error code when I attempt to create a folder on the desktop, for instance. If I attempt to create files via the terminal, e.g. via     ls > foo.txt I get an "invalid argument" error.   I've set the iBook to run in Target Disk Mode and run Disk Utility to repair the disk (from a Macbook running Snow Leopard) and get "The volume appears to be ok".   I don't have the option in Disk Utility to Repair Permissions in Target Disk Mode. When I ran Repair Permissions on the iBook itself, it came back with no errors, no permissions corrected, but did not in fact fix the problem.  Rebooting always solve the problem - for the next 5-10 hours or so.   Would Disk Warrior help, or some other software fix, or is it time to buy a new drive? (And, in any case, what's going wrong?) Cannot edit post meta fields with rest API I am using python to send POST requests to /wp-json/wp/v2/&lt; post type &gt;/&lt; post id &gt;. This successfully updates standard fields such as title, content etc. However I am unable to make any changes to the custom theme meta fields structured like &quot;post_meta&quot;:{     &quot;meta_1&quot;:[],      .      .      &quot;meta_n&quot;:[] }.  When I make a GET request to the same endpoint, the post meta fields are returned so I don't think this is an issue with the fields not being registered? Thanks What does $$ mean in the shell? How was Nearly Headless Nick unpetrified? What is the difference between display: inline and display: inline-block? I am new to Game Development, All I have developed is some 2d Games, using Game Maker by . There game development is much more easy, just as simple as Drag and Drop. But, Now I wish to evolve in Game Development, and wanna try some hands with the common programming languages like, Java, C++ or C. In order to achieve this, I came around the first topic, Game Engine. So, What is Game Engine.? That is a broad question, with various answers. I came out with some conclusion after reading various links,  Wikipedia: A game engine is a system designed for the creation and development of video games. The core functionality typically provided by a game engine includes a rendering engine for 2D or 3D graphics, a physics engine or collision detection (and collision response), sound, scripting, animation, artificial intelligence, networking, streaming, memory management, threading, localization support, and a scene graph.  It exists to abstract the (sometime platform-dependent) details of doing common game-related tasks, like rendering, physics, and input, so that developers (artists, designers, scripters and, yes, even other programmers) can focus on the details that make their games unique. Engines offer reusable components that can be manipulated to bring a game to life. Loading, displaying, and animating models, collision detection between objects, physics, input, graphical user interfaces, and even portions of a game's artificial intelligence can all be components that make up the engine.  Now what I understand is, Game Engine takes care of all the common work, like physics, loading etc... As far my question is concerned, what is a Game Engine (Programmatically)? Is it a Library? With pre-defined functions and classes, which can be inherited? Or what so ever, what is it? When I apply a glossy shader to the material of my text, the text becomes just black. Why?    I have lamp and everything, but the problem persists. The text is red before I add the glossy shader.  I'm using Cycles render.   Thanks! Is there a function to round a float in C or do I need to write my own?