I miss the old , which allowed me, at a glance, to see network activity, memory status and CPU activity.    How do I get something like this back on Bionic Beaver (GNOME on Wayland) ?
I have 4GB RAM. When I open Firefox, IntelliJ IDEA or VS Code and some other application my memory is about used up thus my machine hangs and I can't do anything. I can't even close any applications.    Date and time are shown in the top bar so that I can view it any time without any thing typing.   If I would view memory status in this way without typing anything then I can make a decision whether to open an application or whether this application may put my machine in hanging state or not.    Is it possible in Ubuntu 18.04 LTS?
Prove Uncountable set minus a countable set is uncountable Let B be a countable set, and let A be an uncountable set. Prove that A-B is uncountable Why does kworker cpu usage get so high? I recently installed Ubuntu 12.04 on my Samsung laptop alongside Windows 7. Whenever I use Ubuntu (even when its idle) kworker uses almost 90% of one of 8-cores. Even though it doesn't really affect my usage, it bugs me and I am afraid of that it might harm my processor. I even tried installing another Linux distro (Linux Mint), and kworker caused the same problem. So I don't know what to do. I would really appreciate your  help. Evaluating limit (iterated sine function) The limit is   $$\lim_{x\rightarrow0} \frac{x-\sin_n(x)}{x^3},$$  where $\sin_n(x)$ is the $\sin(x)$ function composed with itself $n$ times:  $$\sin_n(x) = \sin(\sin(\dots \sin(x)))$$  For $n=1$ the limit is $\frac{1}{6}$, $n=2$, the limit is $\frac{1}{3}$ and so on.  Can we define a recurrent relation upon that given hypothesis? Also, how do I involve $n$ into calculation, because the final limit will depend on it?  Any suggestions on how to tackle this?  Thank you! How to ‘guess’ if a noun is countable or uncountable? Install App Image such as beaker browser and pin it to dock (favorites) in Ubuntu 20.04? I accidentally changed /var owner/group to my username and then changed it back to root, but not all the /var folders' owners are root, so is there anyway to change back owner/group of files/folders to default state?  Or at least those files/folders that are created by packages? How to name an item using /give command in MCPE? check if numbers from command line are powers of 2 Deriving Schrodinger equation from Klein-Gordon QFT with the definition $\psi(\textbf{x},t)\equiv \langle 0|\phi_0(\textbf{x},t)|\psi\rangle$ In the book "Quantum Field theory and the Standard Model" by Matthew Schwartz, , the position space wavefunction is defined as   $$\psi(x)=\langle 0|\phi(x)|\psi\rangle, \tag{2.82+2.83}$$  where $|\psi\rangle$ is any state in the Fock space. Then he uses the equations (i) $\partial_t^2\phi_0=(\nabla^2-m^2)\phi_0$ (i.e., the Klein-Gordon equation for the free massive scalar field $\phi_0(\textbf{x},t)$) and (ii) $[H,\phi_0]=-i\partial_t\phi_0$ to derive Eq. 2.85, in following 3 steps:  $$i\langle 0|\partial_t\phi_0(\textbf{x},t)|\psi\rangle=\langle 0|\int \frac{d^3\textbf{p}}{(2\pi)^3}\frac{\sqrt{\textbf{p}^2+m^2}}{\sqrt{2\omega_\textbf{p}}}(a_p e^{-ip\cdot x}-a^\dagger_p e^{ip\cdot x})|\psi\rangle\\ =\langle 0|\sqrt{m^2-\nabla^2}\phi_0(\textbf{x},t)|\psi\rangle.\tag{2.85}$$  This equation is used to successfully derive the Schrodinger equation in quantum mechanics for the state $\psi(\textbf{x},t)\equiv \langle 0|\phi_0(\textbf{x},t)|\psi\rangle$.   The first equality follows from differentiation of $\phi_0(x)$ w.r.t $t$. How does the second equality follow from the first? How are the inputs (i) and (ii) are utilized to derive the second equality from the first? Is it true that the operator $$i\partial_t\sim\sqrt{m^2-\nabla^2}~?$$ If yes, what is the use of doing the middle step? How to compute the marginal likelihood given two multivariate Normal distribution? Given that $a$~$\mathcal{N}(\mu, \Sigma)$ and $\mu$~$\mathcal{N}(0, \sigma^2 I)$, Is $p(a|\Sigma, \sigma)=\int p(a|\mu, \Sigma)p(\mu|\sigma)d\mu$ again a Normal distribution? And how to estimate the mean and variance respectively? Thanks a lot! I have gotten as far as to create the bootable usb, booting into that bootable usb and getting to the install options however i quit because I had some concerns.  I currently have a Samsung 850 evo 1tb that has win 10ninstalled. I want to dual boot with Ubuntu 18.04 by installing it on a brand new unformatted uninitialized Samsung 860bevo 250gb. Should i format the brand new ssd as a new volume in win 10 and then proceed with the Ubuntu install on this volume. What else should i do? Im a first time Ubuntu user and installer.  Any and all help is appreciated. Does anyone have an intuitive explanation (no formulas, just words! :D) about the "$n-1$" instead of "$n$" in the unbiased variance estimator $$S_n^2 = \dfrac{\sum\limits_{i = 1}^n \left(X_i-\bar{X}\right)^2}{n-1}?$$ I was trying to accomplish this through a trigger, but its not really working. Is there a way to get this done through Process Builder? If so, what is that process?  I'm trying to have ProductB being added to the opportunity automatically once ProductA is manually added to the opportunity.  Also, is there a way to have the $ amount of ProductB being 0.5% of ProductA?  Trigger that I have so far:  trigger Attempt1 on OpportunityLineItem (after insert) { List&lt;OpportunityLineItem&gt; oliList = new List&lt;OpportunityLineItem&gt;();  for( OpportunityLineItem item: [SELECT  OpportunityId,                                          Name                                  FROM    OpportunityLineItem                                 WHERE   Id = :Trigger.new AND                                          Name = 'NAME OF PRODUCTA'])  {   oliList.add(new OpportunityLineItem(     OpportunityId = item.OpportunityId,      PricebookEntryId ='01uA000000QPDldEAt',     Quantity = 1,     UnitPrice = 25)   );  }  Insert oliList; } Mark's generosity in this crisis seems to more than make up for his earlier stinginess.   Should those sentences always be avoided, or are there cases where they are valid? how to extract multiple zipped and rar files recursively? I have a folder ExampleFolder which contains many zipped folders. These zipped folders also contains multiple zipped folders. How to go through ExampleFolder and extract all of its zipped folders recursively?   Note that ExampleFolder itself, is not zipped, it's just a normal folder  Okay now I know what's happening Rinzwind and nux answers are both correct (except that I have to keep pressing Y or A forever)  But it's seems that some of the zipped files, contained zipped files and rar files as well, the rar files will not be extracted by   while [ "`find . -type f -name '*.zip' | wc -l`" -gt 0 ]; do find -type f -name "*.zip" -exec unzip -- '{}' \; -exec rm -- '{}' \;; done    or whatever  Edit 2 Some files are named .r00 and r01, .r02 up to r14, they are rar files, but not .rar Is it safe to change the lens on my new DSLR? I recently bought myself a shiny new DSLR camera. Before I can use it, I had to do something kind of terrifying: mount the lens.  Now of course, half the advantage of SLR cameras is that the lenses are interchangeable. But sitting there holding an extremely expensive brand new camera and staring into its bare innards, I'm just terrified that if I make one wrong move, a hair or a piece of dust could fall in there, and then the camera will be irreparably damaged and I'll never be able to use it again.  This might sound like a stupid question, but&hellip; is it actually &ldquo;safe&rdquo; to change the lens on the camera? Is this likely to destroy it?  (Obviously it goes without saying that you should limit the time spent with no lens attached to the minimum number of seconds possible. But even if you have lightning fingers, the camera will still be lenseless for some number of seconds. And it's not like I'm standing in a class 100 cleanroom here! Besides, you don't want to be too rough with the delicate lens mounting either&hellip;) Beryllium Vacuum Sphere Boat/Aircraft Is it possible to make a solid rigid evacuated "balloon" out of Beryllium or other elements or alloys?  The critical buckling pressure at which an evacuated sphere is given as $$ P_1=\frac{2E\cdot\left(h/R\right)^2}{\sqrt{3\left(1-\nu^2\right)}} $$ where $E$ is , $h$ the shell's thickness, $R$ the radius to the midsurface shell, and $\nu$ is .  Of course this is theoretical and experimental and literature values for submersibles hover around 1/4 of the theoretical pressure.  Beryllium has the following properties:   Density=1.85 g/cm$^3$ Young's Modulus=287*10$^9$ Pa Poisson Ratio=0.032   Calculating the upward force, buoyancy at 101.3 kPa atmospheric pressure and Radius of 10m gives 4.24*10$^8$ N. The weight of this sphere with shell thickness 1mm has 2.32*10$^7$ N downward force of Beryllium material, so it will theoretically float at ground level.   Calculating the critical buckling stress of this beryllium sphere is 331.57 kPa, which is 3.27 times the atmospheric pressure of 101.3 kPa, so theoretically it won't buckle. But in experimentation done in earlier experiments as stated before, due to construction/material non-ideal situations, the critical buckling formula predicts about 4 times stronger than actual, so it would need about 400 kPa, not 331 kPa as Beryllium sphere with this specification would hold. Increasing the strength capability also increases weight and therefore lowers it's ability to float, but Beryllium is the closest element with this situation I have calculated that could work if ideal (I have only been using periodic table elements and household materials)  Is it possible with an alloy of elements? Using the equations for buckling and buoyancy, the following is needed. What alloys/materials come to your mind?  Material considerations:   Material with larger Poisson ratio Material with larger Young's Modulus Less dense material Construction (is it possible)   Material considerations affect on lift   Thickness can be larger, increases strength by the squared. But also increases weight. If a material with lower density with similar structural properties as Beryllium is used, it would help. Radius can be lower for same reason, but also lowers buoyancy (volume)   My other designs (don't worry about these just yet, just if you are curious is a vacuum sphere with a pressurized "outer tube" with spokes in tension (carbon fiber nanotubes maybe) to keep the 2 spheres in position. Another is a spherical truss out of carbon fiber nanotubes with a light membrane around. The truss prevents the outer membrane from collapsing due to the atmospheric pressure  The "point" of this if you ask, as to why not use a traditional balloon is it can be used as a boat by filling the sphere with air, and then used as a aircraft at will by evacuating the sphere. An alternative mode of transportation for sea vessels etc. In X-Men Origins: Wolverine,      Wolverine is shot through the head with what appears to be a vibranium bullet by William Stryker. He remarks that the brain will grow back but the memories won't.   So the projectile penetrated the adamantium skull and damaged the brain. Adamantium is an inorganic substance. It will survive anything that would otherwise destroy the rest of Wolverine's body. But if anything (such as vibranium) manages to damage the adamantium, it is not covered by Wolverine's healing abilities.  Does this mean that Wolverine has an Achilles' heel on his forehead? If so, how did he take a bullet to the exact same spot in X-Men: United (at Ice Man's home)? Which files shouldn't be checked in into version control in Android Studio Display top tags & percentiles from additional Stack Exchange sites on Careers Are the "top tags &amp; percentiles" from Stack Exchange sites other than Stack Overflow displayed in the Careers site?  If not can they be added?  If they are, then what are the requirements for them being displayed in the Careers site?