Ubuntu installed in VirtualBox has blurred screen
Graphics horribly corrupted on Ubuntu 16.04 in VirtualBox, showing random strips of pixelated colors
If a Matrix Has Only Zero as an Eigen-Value Then It Is Nilpotent Is every sub-lattice of $\mathcal P(X)$ isomorphic to a sub-lattice of $\mathcal P(X')$ containing singleton sets? Is the Jekyll blog dead? I noticed that the  is apparently abandoned and the  is back to WordPress.  I'd be interested to know what were the decisions that led to switching back. Was the content creation process hindered by Markdown + git? Were there growing pains that couldn't be solved? How to load and parse SVG documents Why did Bane/Smith cut himself? In the Matrix part II and the beginning of part III the crew member who was infected by Agent Smith (Bane) cuts himself.   The female crew member in part III who brought Trinity food told her the same and speculated that they might be "VDT's".  I don't fully understand this. What are VDT's and why would Agent Smith engage in self-cutting unless he has borderline personality disorder or depression or something? Can I cast a spell while another spell or ability is resolving? My opponent has a  with scads of loyalty. I've got a  and a  on the battlefield.  He activates Sorin's "ultimate" ability, targeting Gideon.     -6: Destroy up to three target creatures and/or other planeswalkers. Return each card put into a graveyard this way to the battlefield under your control.   Is there any way I can use the Spellbomb to prevent my opponent from stealing Gideon after he is sent to my graveyard? When in Journey Builder what is the difference between journey data and contact data? I am creating a JB with an engagement split. What is the difference between Contact Data and Journey Data. ie what will I see listed in the two groupings. If I choose the journey data will this only be as up to date as the time that the data entered the Journey? Why not brew wine and make beer? Non native speaker so I can't fully discern the difference.  Thanks. Most of the time, I use good and well interchangeably. However, on many occasions I would find well or good a misfit. Please suggest the proper usage. I guess I can live with the fact that the  changes size drastically when he transforms, but why does his shirt rip off and not his pants?  I think that we need a little better answer than "it keeps us tied to the fact that inside he's still human". I had always kind of wondered why we didn't see interference in things like windows -- we were taught that the condition is that the thickness of the film/slab/medium just has to be an integral number of wavelengths, $d=m\lambda$. My logic was, if visible light has wavelengths ~400-780nm, any window pane has got to be an integral number of wavelengths (or close to integral) for some of the wavelengths in the visible.  For example, if a window is, $6mm = 6\times10^6nm$ thick, then you should see interference for wavelengths (and some range around them) 200nm, 250nm, 300nm, 400nm, 500nm, 600nm... Because 6mm is an integral number of each of those.  Obviously that would be really annoying and isn't the case. I found  (warning: PDF) source that seems to explain it and I was wondering if what they're saying is sound. On the 10th page (p171 for them), it says that the reason we don't see this interference is that no window is that smooth, it has a variance in the thickness of at least several wavelengths, so the interference effect is effectively average out among all those thicknesses, which usually gets rid of it. They do the math and show that.  Is that the reason?  If so, that leads me to two questions: Could we, if we were really careful and used something like MBE, make a glass window with that sort of accuracy, and then see interference effects in the optical range? I know that quartz crystal monitors can easily give you nanometer accuracy for evaporators and sputterers, but they also have pretty limited growth rates.  My second question is, then, do we see interference effects in glass windows with electromagnetic radiation of a comparable wavelength, like microwaves?  Thanks! When should I use the subjunctive mood? How do I copy vertex groups from one object to another? I have a set of coordinate points. The points are distributed in such a way that some points are clustered around a specific area. There is an option to find out mean coordinates(s) of the whole point layer. I would like to know if there is any way in QGIS to find out the mean coordinates of the points from a specific area from a point layer. Why is energy in a wave proportional to amplitude squared? I'm a mathematics student trying to grasp some basics about wave propagation. A sentence I find very often in introductive physics textbooks is the following:      In a wave, energy is proportional to amplitude squared.   This is something I would like to understand better in the case of mechanical (linear) waves.  The simplest model is the vibrating string of mass density $\mu$ and tension $T$: here an element of string of rest length $dx$ and vertical displacement $y(x, t)$ possesses a kinetic energy $\frac{1}{2}\mu dx \left( \frac{\partial y}{\partial t}\right)^2$ and a potential elastic energy $\frac{1}{2}T dx \left( \frac{\partial y}{\partial x}\right)^2$. So we have the total energy   $$dE=\frac{1}{2}\mu dx \left( \frac{\partial y}{\partial t}\right)^2+\frac{1}{2}T dx \left( \frac{\partial y}{\partial x}\right)^2,$$  which completely explains the sentence. Can we obtain a similar formula for higher-dimensional waves? How should I modify the above formula for a (simplified model of an) elastic membrane, for example? I would expect something like   $$dE=\text{some constant}\left(\frac{\partial z}{\partial t}\right)^2+\text{some other constant}\left\lvert\nabla z\right\rvert^2,$$  where $z=z(x, y, t)$ is the vertical displacement. Am I right? self referential struct definition? Stopping to eat is tedious, is there any way to automate the process? While I've managed to optimize and automate almost everything, constantly having to stop and eat is annoying (I run around a lot, so I get hungry quickly). Is there any device or tool that will keep me well fed at all times without having to stop and feed? I have an entry-level Nikon DSLR, and I cant decide if I should upgrade my camera body or upgrade from a  AF-S DX Nikkor 18-200mm to whatever else might be recommended? FM Transmitter oscillation problem I've been trying to get this simple FM transmitter to work over the past few days and I could use some help in a few areas.      First iteration was on a breadboard with all parts included.  The exception being I didn't have a 0.1uH coil handy but I had another coil rated at 0.7uH (using my LCR meter).  I also didn't have a C4 value of 4.7pF but I had a 10pF value.  I figured I could just tune it later.  I hooked a scope up to it and got no oscillation.  I tried connecting the probe to the gate and the collector separately and together.  Still no oscillation.  Second iteration.  I removed the audio component of the circuit.  Essentially everything to the left of C2.  I had gotten that working no problem anyway so I figured I would concentrate on the oscillator.  This time I tried different values for the inductor ranging from 20uH to 1mH and different fixed values for the variable cap (10pf, 20pf, 30pf).  These were all ceramic caps. No love.  Third iteration. I tested the transistor to make sure that wasn't the issue.  Seems fine.  PN2222A variety. (Also tried 2N3904 and BC547). I then modeled this up on a piece of perf board.  I even found a SMD inductor of 0.1uH so now I thought I would be good.  Tested all the pieces on the meter before installation. Still nothing. I'm not seeing anything on the spectrum analyzer either.  Questions:   Do you think my benchtop power supply is causing a problem?  All the various versions of this type of FM transmitter circuit on YouTube and the Internet all seem to use a battery.  Any chance the 60Hz main power is messing with things?  I've put .1uF and higher caps on the power rails. I have a 200Mhz SIGLENT SDS1202X-E scope.  I've built and tested other oscillators up to a few MHz before with no issues.  Any thoughts on that being the issue?  I would expect to see something on the scope right? Any chance the probe is dampening the oscillations?     I know there are a lot better FM transmitter circuits out there I was just experimenting with this (and others like it) and couldn't get any to work. What flash slaves can be used with a Canon Speedlite 600EX-RT? My current flash setup is a standard shoe mount but I've been thinking about getting a remote.  I've been drooling over the Speedlite 600EX-RT. It uses radio to control slaves, which is nice (longer distance, doesn't require line of sight, etc.).  One thing I don't understand: do slaves also have to be 600EX-RTs or do other flash units use radio to communicate already? Can any (cheap?) flash slaves can be used with a Canon Speedlite 600EX-RT or do I need to buy the 600EX and a ST-E3-RT transmitter in order (or multiple 600EX-RTs) to have a radio-controlled remote flash setup?