Asus g53 laptop, Ubuntu 14.04, KDE 4.13.3  Fn+{f5f6} should change the screen brightness but only the animation appears with the panel (I can increase the values but the brightness does no change)   I have already tried to add this to grub  GRUB_CMDLINE_LINUX_DEFAULT="quiet splash pcie_aspm=force acpi_backlight=vendor"   Does not work. I tried this one too, I do not know what should happen after the first command but I just got back the console without anything seeming to happen:   I have also installed this    On GNOME and Unity this function works like a charm. Why not on KDE? Keyboard backlight is working on KDE.
I've installed Ubuntu 16.04 on my Asus X555LJ.  But I don't know how to install drivers or how to enable function keys to controls screen backlight brightness.
Can I bring a pack of razor blades on a plane? I have to take a flight soon and I want to know if I can take a pack of razors with me. They are in a pack that is designed to not let any out unlesss a person really wants to open it. I'm going to the USA so, can I?  I mean plain old razor blades: How can I record sound from the windows command line? Is there an application capable of recording sound that I can run from the command line on XP?  Ideally I'd start it with one command and stop it with another. Or I could specify a duration with the starting command. Spacelike interval and length contraction I am having a serious trouble finding an agreement between the two facts in Special Relativity:  (1) given two events $A$ and $B$ in spacetime separeted by a spacelike interval $s$, the distance in space between the two events will be the shortest in the reference frame which the two events occur simultaneously:   The invariance of the interval says $s^2=(\Delta x)^2-(c\Delta t)^2$ and $\Delta x$ is minimum when $\Delta t=0$  (2) the length contraction says $L=\dfrac{L_0}{\gamma}$ where $\gamma=(1-(v/c)^2)^{-1/2}$ , $L_0$ is the proper length of an object in a reference frame which the object is at rest and $L$ is the length of the object in a reference frame which the object moves with speed $v$ in the $x$ direction.  This says that the lenght of the object in the $x$ direction is the largest in the comoving reference frame of this object.  The question is: According to (1), the reference frame in which two events $A$ and $B$ occur simultaneously is the reference frame that gives the shortest distance in space between the two events. Let $A$ and $B$ be the two end points of a meter stick in a reference frame in which the stick is at rest and at time $t=0$. This two events occur simultaneously, so the distance in space between the two is the shortest acording to (1). But according to (2) shouldn't this distance be the largest?  What is wrong? Feedback Request: New Timeline Question View There is an experimental timeline view for questions now available on meta ONLY! (Now working on SO, SF, and SU as well)  This is partially motivated by comments about how difficult it is to follow very active questions which have a lot of activity, and also the feedback on the API which was heavily dominated by "we need to know what happened in this time range" type responses.  It can only be accessed through URL hackery at the moment. To get to it, enter question URLs like so:  https://meta.stackexchange.com/posts/{id}/timeline  This is a chronological timeline of everything that happened on a question, including   initial question ask answers  revisions comments closure, deletion, reopen, undelete, etc votes   all based on when they happened in chronological order.  We are thinking about making this a fourth tab on the question, like so:  Timeline | Oldest | Newest | Votes  Please try it out and provide feedback. It is still a little rough, so we are not looking for highly detailed bug reports, just more general feedback.  Timeline view for this question: Java Generics: List, List, List As a lab assignment I have to replicate experiment with spring oscillations, and eventually calculate spring constant. The measurements I took are: spring displacement from equilibrium $x$, mass of weights $m$, and period $T$. And presumed uncertainties: $\Delta_\alpha(x)=1[mm]$, $\Delta_e(x)=2[mm]$,  $\Delta_\alpha(t)=0.1[s]$,  $\Delta_e(t)=1[s]$. Where $\alpha$ stands for uncertainty of used equipment, and $e$ is readings uncertainty made by me.  I calculated the standard uncertainty using this formula: $$\sqrt\frac{\Delta_\alpha(x)^2+\Delta_e(x)^2}{3}$$ Which produced $u(x)=1.29[mm]$. Then using the following substitutions:  $$F=kx$$ $$mg=kx$$ $$x=\frac{g}{k}m$$ I assert that:  $$tan(a)=\frac{g}{k}$$  Because in this part of experiment I plotted $x=f(m)$, using excel's linest, I get the slope $s$  $$tan(a)=\frac{g}{k}=s$$  Now, my question is, since I had uncertainty for $x$ introduced, and it is used to compute $tan(a)$, then the latter is affected and should have uncertainty of itself? How in this case should I go about propagating uncertainty to $tan(a)$? Show: $ f(a) = a,\ f(b) = b \implies \int_a^b \left[ f(x) + f^{-1}(x) \right] \, \mathrm{d}x = b^2 - a^2 $ How can I disable creepers' block damage on my Minecraft server? Please note that these are NOT acceptable solutions:   Completely disabling monsters (peaceful mode) Completely removing creepers Completely disabling explosions (TNT + Creepers) Disabling creeper explosions   More exactly, I want the creepers to be able to spawn and explode, but without doing their terrain damage (they should still be doing health damage to the players).  I'm fine with the use of mods but I'd prefer a built-in solution if possible. Age of universe? Well relativity teaches us that time interval between two events is a frame dependent quantity, then how can we say that our universe is 13.8 billion years old? Should it not depend on who is asking this question? Why didn't Snape keep or secure his copy of Advanced Potion-Making? Construction of $\mathbb{CP}^2$ from $S^2\times S^2$ Show that $\mathbb{CP}^2$ is homeomorphic to the orbit space of $(S^2\times S^2)/\mathbb{Z}_2$. The action is given by $(x,y) \mapsto (y,x)$. My attempt: I can see that $S^2\times S^2$ is a subset of $S^5$. I am unsuccessfully trying to restrict the action of $S^1$ on $S^5$ to $S^2\times S^2$ to get the required map. Lebesgue measure of the set of zeroes of Brownian motion Let $B_t(w)$ be a Brownian associated with a measure $P(dw)$. Suppose that $X$ is a random set of times $t$ where $0 \le t \le 1$ such that $B_t=0$. Show that $X$ has Lebesgue measure zero $P$ almost surely. With the exception of multiclassing, is there any big reason that if you were to change the spellcasting ability of a (spellcasting) class it would be a bad idea?  As a specific example: Let's say I was switching Sorcerers from Cha to Wis, what unexpected effects could this have on that class's balance? Additionally let's assume all places in spellcasting where you added your charisma modifier instead you now add wisdom (and vice-versa). What is the intuition behind beta distribution? Disclaimer: I'm not a statistician but a software engineer. Most of my knowledge in statistics comes from self-education, thus I still have many gaps in understanding concepts that may seem trivial for other people here. So I would be very thankful if answers included less specific terms and more explanation. Imagine that you are talking to your grandma :)  I'm trying to grasp the nature of beta distribution – what it should be used for and how to interpret it in each case. If we were talking about, say, normal distribution, one could describe it as arrival time of a train: most frequently it arrives just in time, a bit less frequently it is 1 minute earlier or 1 minute late and very rarely it arrives with difference of 20 minutes from the mean. Uniform distribution describes, in particular, chance of each ticket in lottery. Binomial distribution may be described with coin flips and so on. But is there such intuitive explanation of beta distribution?    Let's say, $\alpha=.99$ and $\beta=.5$. Beta distribution $B(\alpha, \beta)$ in this case looks like this (generated in R):     But what does it actually mean? Y-axis is obviously a probability density, but what is on the X-axis?   I would highly appreciate any explanation, either with this example or any other. I keep reading articles about CCD vs CMOS image sensors. What is the difference between these two types? What exactly do these sensors do in terms of photography?  Is a CCD-based camera going to be able to compete in the future? If I buy one, can I count on using it for some years or would it be better to upgrade to a camera with a CMOS based sensor? How are parentheses interpreted at the command line? Should I file Form 1040 or Form 1040 NR? I am currently on H1 B (since October 1, 2017). Last year when on F1 OPT, I had filed Form 1040 NR for my taxes. Which form is advisable for 2017, considering I am on H1 B now. What options do I have? Finding the contact point with SAT Can Mjolnir be lifted & wielded by anyone if Thor is touching it? In The Big Bang Theory episode , Penny, Amy, and Bernadette are having an argument if Thor's hammer:   Can be lifted by anyone in space.     Can be lifted &amp; wielded by anyone if Thor is touching it.   The first argument is settled in .  But the second argument remains unsolved.  Can Thor's hammer be lifted &amp; wielded by anyone if Thor is touching it? Can we theoretically balance a perfectly symmetrical pencil on its one-atom tip? I was asked by an undergrad student about this question. I think if we were to take away air molecules around the pencil and cool it to absolute zero, that pencil would theoretically balance.  Am I correct?  .