can not make Caps Lock a Control key using setxkbmap
How can I change what keys on my keyboard do? (How can I create custom keyboard commands/shortcuts?)
Why is "the set of all sets" a paradox, in Layman's terms? I've heard of some other paradoxes involving sets (i.e., &quot;the set of all sets that do not contain themselves&quot;) and I understand how paradoxes arise from them.  But this one I do not understand. Why is &quot;the set of all sets&quot; a paradox?  It seems like it would be fine, to me.  There is nothing paradoxical about a set containing itself. Is it something that arises from the &quot;rules of sets&quot; that are involved in more rigorous set theory? In low-cost mass-produced items I often run into black blobs of what looks like resin applied directly on top of something on the PCB. What are these things exactly? I suspect this is some kind of custom IC that is layed out directly on the PCB to save on the plastic  housing/connector pins. Is this correct? If so, what is this technique called?    This is a photograph of the inside of a cheap digital multimeter. The black blob is the only non-basic piece of circuitry present, along with an op-amp (top) and a single bipolar junction transistor. Div's class vs id When using divs when is it best to use a class vs id?   Is it best to use class, on say font variant or elements within the html? Then use id for the structure/containers?   This is something I've always been a little uncertain on, any help would  be great. Prove that $2xy\mid x^2+y^2-x$ implies $x$ is a perfect square. Prove that $2xy\mid x^2+y^2-x$ implies $x$ is a perfect square. My work: $2xy\mid x^2+y^2-x \implies x^2+y^2-x=2xy\cdot k$ So,$x^2+y^2+2xy-x=(x+y)^2-x=2xy \cdot (k+1)$ And,$x^2+y^2-2xy-x=(x-y)^2-x=2xy \cdot (k-1)$ I found that for $x,y$ both odd, no solution exists. For $x$ even, and $y$ odd,no solution exists. Solution exists only for $x$ odd, $y$ even and $x$ even and $y$ even solution exists. Cannot do anything more. Please help! How do I give myself an item that can only be placed on a block with a certain damage value? Principal component analysis "backwards": how much variance of the data is explained by a given linear combination of the variables? I have carried out a principal components analysis of six variables $A$, $B$, $C$, $D$, $E$ and $F$. If I understand correctly, unrotated PC1 tells me what linear combination of these variables describes/explains the most variance in the data and PC2 tells me what linear combination of these variables describes the next most variance in the data and so on.   I'm just curious -- is there any way of doing this "backwards"? Let's say I choose some linear combination of these variables -- e.g. $A+2B+5C$, could I work out how much variance in the data this describes? Why can't Chromium suddenly access any partition except for /home? I just upgraded to Ubuntu 19.10 and to my horror I discovered that the default browser Chromium can no longer access other partitions than /home.  This means that my partitions containing music and videos (/multimedia) for instance are no longer accessible e.g. to upload into Google Drive. This includes USB partitions.   I found another description of this phenomenon here:  where it says  "Also, while we acknowledge that most users will only need to access their home folders, it’s worthy to mention that you no longer can access system files &amp; folders from inside Chromium (You can’t access anything except your home folder). This means that if you are to upload a file or an image for example into the Internet using an uploading website, then this file/image must be in your home folder, as you can not access directories such as /usr, /etc or other directories located in your root partition. In fact, you no longer can access any other partition at all, this includes USB sticks and other booted partitions:"  I wonder why this behaviour been introduced? it violates the whole idea of multiple disks, partitions and symlinks. Btw, this still works for Firefox.  My questions are   Are there any plans to fix this? I expect one reason for this behaviour is about security. If so, is it possible to explain why and how that makes for better security? The files on other partitions are legitimately accessible by the user anyway e.g. through symlinks. But with this change, I'll have to move them to /home before uploading so still accessing them although more slowly and cumbersome.  If this behaviour is now permanent, the question is how should we incorporate multiple disks in our filesystem?  Alternatively, can someone tell me how to find and install the debian package. I haven't been able to locate it?   This is not a duplicate of  because that is about a specific error during installation that I didn't get. My question is about the access chromium has in Ubuntu 19.10.  Anyway, I solved the problem via the following command by using the original debian package from Google:  sudo apt-get install google-chrome-stable   After that I can now access my other partitions again. I know this is hacky in the sense that the package isn't native to Ubuntu so I would really like to get some advice on how to incorporate multiple disks and partitions with this new restricted behaviour of Chromium.  Thank you very much Find count of all combination of numbers whose sum is x Strange distance measurements in distance matrix I'm trying to create a distance matrix between two point shapefiles in QGIS 2.6. Both are in WGS84 UTM Zone 30N co-ordinates (and so is the project file), but the distance matrix returns values such as 5673346.938, instead of expected numbers of between 1 and 5km.  I saw a similar thread mentioning disabling 'on the fly projection changes' - I've done this, and no change. Threads already checked:     Here are samples of the two shapefiles I'm using, stripped down to just ID and location. How do I add a Pokestop to my area? How do I add a Pokestop to an area that has none? It is an area where there are tons of businesses but unless I drive about a mile from my work area there are no Pokestops.   I want to add one since we have 1000's of people in the work area, a lot of them play Pokemon Go, and we all can't leave work to drive a mile away to get to a Pokestop area.   Plus it would be nice to be able to capture Pokemon on our breaks. I'm DM'ing a play-by-post campaign and I'm at a point in the adventure where the group all meets for the first time. They've all had something stolen from them at the same time and saw a creature that took something run into a nearby alley (there's three separate parties within the play group currently, as they've only just started, so there's three separate robbers running into alleys in the marketplace).  Ideally, I want the players to have their PCs all give chase so they end up in the same part of town, all looking for the same thing. However, I don't want to railroad my players into doing this. I know I'm not supposed to take away player agency or narrate their actions for them, but the only way I could think of was to tell them that they start giving chase.  So how would you deal with this situation? And more broadly, how can I stop something like this happening again?  If it matters, we're currently playing D&amp;D 5e. Are film capacitors affected by DC bias? After looking around, I have found quite a few things about how DC bias reduces effective capacitance for a ceramic, or electrolytic capacitor, however nothing seems to talk about the effect on film capacitors. I've found a couple of papers about film caps (such as: ), and they mention frequency and temperature, but I can't find anything about DC bias reducing capacitance.  I have obviously checked the data sheet of the component I plan on using (), but there isn't anything about DC bias in that (unless I've just failed at spotting it).  This suggests to me that they aren't affected by DC bias, but that seems a bit of a bold claim, and I can't see that stated anywhere.  Are film capacitor values affected by DC bias? If so, can anyone point me to some data about what the roll off is?  I am planning to use some film capacitors in an application with 48-60V DC across the capacitors and a ripple current around 30 amps. There are a number of times in Lord of the Rings where the "east" is mentioned -- the pirate ships, the slave-driven farms. And of course all of the peoples subservient to Sauron who come to fight Gondor and the West. Are there any maps of the East of Middle-earth, and what is out there? Determine app sending SMS Premium messages I normally have "Block Premium Messaging" set up on the phones in my family. This is a verizon content block the prevents you (or family members) from sending messages to premium services that charge.  Recently, I had to replace a phone that broke and when the new phone was activated the blocks I had set up were cleared. On my bill was a $9.99 charge for a text to one of these premium services.   I know nobody sent the SMS to the service to sign up for this. I suspect some application on the phone sent the SMS message. Is there a way I can find out which app on my phone is sending SMS messages to premium services? Can I view all the apps that have permission to send SMS messages?  -- update -- well, I ran RL Permissions and no downloaded apps have the Send SMS permissions. I must have already deleted the offending app or something else is going on. Meaning of Simplify's tolerance parameter The standard parameters of Douglas-Peucker's simplify algorithm are geometry and tolerance (e.g  in PostGIS). What's the meaning of the tolerance parameter? I know that the bigger the value, the coarser the geometry will be. But does the number has any unit or it is just arbitrary? Why does pluralization of compound words typically occur in the middle as opposed to the end of the word? As I understand, correct plural versions of passerby and attorney general become passersby and attorneys general.  But why?  With passerby, the the preposition "by" has been combined with the noun "passer" to become a one word noun "passerby".  So why shouldn't this be passerbys?  If I am an attorney general, and you are an attorney general, why are we not attorney generals?  As an American I have always heard it as attorneys general, however  suggests British English does use "attorney-generals" (as well as an interesting 2nd paragraph that further probes my question).  Are there hard rules to this topic?  Or merely generally accepted practices based on locale? How to ensure that string interpolated into `sed` substitution escapes all metachars D'Alemberts Principle to solve a Classical Mechanics problem I found this question on this very site and was curious on how to solve it using D'Alembert's Principle  .I already know how to do it by balancing the torque about toppling point so please don't post the latter as an answer . My attempt was to displace the upper sphere by $d\theta$ which gives its virtual displacement as  $rd{\theta}cos(\theta)$j(notice we are only interested in the y component becuz the only component of the applied force which is gravity in this case is the y component in the dot product the other components vanish) similarly the cylinder is also displaced $r'd{\phi}cos(\phi)$ where r' is the distance from the point of toppling of the center of mass. $r'cos(\phi)=H/2=r(1+sin(\theta))$ ,$r'sin(\phi)=R=r(1+cos(\theta))$ and $tan(\phi)=H/2R$ the equation coming from D'Alemberts principle is $mgrcos(\theta)d\theta=Mgr'cos(\phi)\phi$ I tried solving this but couldn't arrive at the right answer. Any help would be appreciated! When looking at my Apache2 access logs, I occasionally see GET requests asking my server for a page on a completely different server. For example:  xx.xx.xx.xx - - [18/Jan/2012:07:12:10 -0500] "GET http://someotherserver.com/?sometimesmorestuff=likethis HTTP/1.1" 200 389 "-" "Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.8.1.12) Gecko/20080201 Firefox/2.0.0.12"   I remembered reading something about that in the past, but at the time I had never seen that on my server, so I didn't worry about it.   Now that I am seeing it on my server, I just ran a test and it appears that my site does indeed serve requests for content from other servers. This seems like a bad thing. So, two questions:  A) Is this something I should be worrying about?  B) How can I fix it?  I've tried a little Googling, but I don't even know what this sort of thing is called, and that makes it difficult. Why and how does ([![]]+[][[]])[+!+[]+[+[]]] evaluate to the letter "i"?