Without installing snapd, How to install ubuntu software centre?
Has 'Ubuntu Software' been renamed to 'Snap Store'?
jQuery 1.9 checkbox not checked second time after once it unchecked How do I get the Glare node to output transparent instead of Black background Suppose $m_1, m_2, m_3,\ldots, m_k &gt; 1$ and not necessarily pairwise relatively prime. Also $a_1, a_2,\ldots, a_k\in\Bbb Z$. What can we say about the solutions of the following congruence equations: $\begin{align*} x&amp;=a_1\mod m_1\\ x&amp;=a_2\mod m_2\\  &amp;\phantom{1}\vdots\\ x&amp;=a_k\mod m_k \end{align*}$ I just came across this idiom in some open-source Python, and I choked on my drink.  Rather than:  if isUp:     return "Up" else:     return "Down"   or even:  return "Up" if isUp else "Down"   the code read:  return isUp and "Up" or "Down"   I can see this is the same result, but is this a typical idiom in Python? If so, is it some performance hack that runs fast? Or is it just a once-off that needs a code review? Excel function that evaluates a string as if it were a formula? Proof of matrix norm property: submultiplicativity I've been searching for the definition of the submultiplicative (I think it has multiple names from what I've seen) property in proof form. Some books define it as part of the properties that define matrix norms, and some include it as an additional property. I still haven't been able to work it out for myself or find it anywhere.  Let $A$ and $B$ be $n\times m$ and $m\times l$ matrices respectively, prove that:  $$\begin{align} \|AB\| \le \|A\|\|B\|  \end{align}$$ Set "older" kernel as default grub entry I installed a mainline kernel for testing purposes. I would like to set grub to boot from the older kernel by default.  I know I can set the GRUB_DEFAULT=0 setting for the first page of grub but how do I set it to boot by default from one kernel in the second page (Advanced page)?  I would prefer doing this without installing other software (ex. grub-customizer).     Related Questions: It is said in many textbooks that alpha decay involves emitting alpha particles, which are very stable. Indeed, the binding energy () is higher than for $Z$-neighboring stable isotopes. But the binding energy is lower than, for example, ${}^9\mathrm{Be}$ (). My question is why aren't other nuclear compounds ejected from heavy nuclei, e.g. ${}^9\mathrm{Be}$?  The   $$e^{-\frac{4\pi}{\hbar}\frac{Ze^2}{4\pi\epsilon_0}\frac{1}{v_\alpha}}$$ decreases exponentially in $Z$, so it explains intuitively why lower-$Z$ particles would tunnel more often. Specifically, it would explain why we would see ${}^9\mathrm{Be}$ emission ${e^{-2}}\simeq 0.14$ times as often compared to ${}^4\mathrm{He}$ emission. Also, the particles need to form in the nucleus prior emissions; but with a similar binding energy per nucleon (~7.08 MeV for ${}^4\mathrm{He}$ vs. 6.47 MeV for ${}^9\mathrm{Be}$) and higher total binding energy for the ${}^9\mathrm{Be}$ nucleus, I would expect that its formation in the same order of prevalence as the alpha particle (according to Ohanian, between 0.1 and 1 alpha particles are in existence at any moment in time).  Can anyone explain this? A reference to an article/textbook would be preferable.  EDIT Same goes for ${}^{16}\mathrm{O}$ which is also a double magic isotope, as 'anna v' pointed out. For it, the Gamow factor is smaller by $e^{-4}\simeq 0.02$, and emission should still be viable. Why $\gcd(qb+r,b)=\gcd(b,r)$? I lost the source code from one project I did on the company I'm working for and haven't been able to find a Visual Basic 6 decompiler; does that even exists?  I only have the EXE that I've rescued from a user's machine. How to remove the lines which appear on file B from another file A? Will I be able to use my NTFS data partition in Ubuntu? My machine is currently running Windows 7. I have 2 partitions: OS (C:) and DATA (D:). I intend to do a native Ubuntu 14.04 install. Assuming I format my Windows OS partition, will I have full access to my D partition in Ubuntu ? What is the function of the RNA primer in DNA replication? During DNA replication, RNA primase puts an RNA primer in the lagging strand. What is the function of this RNA primer? Why can't the enzymes put DNA fragments directly? The union of a strictly increasing sequence of $\sigma$-algebras is not a $\sigma$-algebra Why are moderators now required to report underage users? Just today (December 2, 2020), a  was enacted, which requires moderators to report users that they find to be underage:  If you find a user claiming to be under 16 escalate it to us through the &quot;Contact Community Team&quot; button and select the &quot;underage user&quot; template - this will flag the on-duty CM for action so we can investigate and, if deemed necessary, delete that account and all personal data associated with it. [...] This policy only applies to sites where you are a moderator. If you see things on a site where you’re not, there is no obligation to escalate.  Being part of the , moderators are required to follow the instructions there, and not following them is considered a violation of the moderator agreement. However, this contradicts a , which states (bold added):  Users and moderators are not legally responsible for underage users and are under no obligation to report them to us. If out of concern you would like to report it, [...]  As part of the re-enaction of the policy on December 2, the text &quot;and moderators&quot; in the above quote was edited out of that statement. Why are moderators now required as per policy to report underage users that they come across? Is there a legal explanation as to why SE's stance on this changed? I'm aware of  from a then-employee, which stated that moderators are expected, but not required as a condition of remaining a moderator, to report underage users. However, the new policy requires reporting them. Why? An example of a case where a moderator may not want to report an underage user is if the user claims to be from an EU country that has reduced the required age from 16. While SE's Terms of Use specify a blanket limit of 16 to comply with regulations in all EU countries, individual member states do have the ability to reduce the limit, so long as it's not below 13. There is no law violation if, say, a 15-year-old user from an EU country that has reduced the age limit to 14 registers, so a moderator may not feel like reporting them (since in that case they're merely enforcing the Terms of Use, which they're not otherwise expected to do).  The policy was recanted a few days after it was originally enacted on October 15, 2020, but was enacted again on December 2 after minor revisions following a review among moderators. The same question still applies to the revised policy, however. Proof a graph is bipartite if and only if it contains no odd cycles How can we prove that a graph is bipartite if and only if all of its cycles have even order? Also, does this theorem have a common name? I found it in a maths Olympiad toolbox. Our team is developing a new system and it has a Warehouse table that must have a hierarchical relationship between entries since a customer can have 1st, 2nd, 3rd and Nth degree warehouses.  We first thought that  was the best way to do it. By creating a Parent and a Child column on the table and then making Parent the FK to Child (on the same table) but friend DBA told us that there is a different way.  So, for instance, we had thought about making a table like this:  CREATE TABLE Warehouse( filterId INT PRIMARY KEY IDENTITY, parentId INT NOT NULL, active BOOL DEFAULT 1, warehouseName VARCHAR(30) NOT NULL, FOREIGN KEY parentId REFERENCES Warehouse(filterId)  | FILTERID   | PARENTID | ACTIVE | WAREHOUSENAME | -------------------------------------------------- |          1 |        0 |      1 | N WAREHOUSE 1 | |          2 |        1 |      1 | ROOM 1        | |          3 |        1 |      1 | ROOM 2        | |          4 |        1 |      1 | ROOM 3        | |          5 |        1 |      1 | ROOM 4        | |          6 |        2 |      1 | SHELF 1       | |          7 |        2 |      1 | SHELF 2       | |          8 |        2 |      1 | SHELF 3       | |          9 |        2 |      1 | SHELF 4       | |         10 |        2 |      1 | SHELF 5       | |         11 |        2 |      1 | SHELF 6       | |         12 |        2 |      0 | SHELF 7       | |         13 |        3 |      1 | BOX 1         | |         14 |        3 |      0 | BOX 2         | |         15 |        3 |      1 | BOX 3         | |         16 |        3 |      1 | BOX 4         | --------------------------------------------------   But this DBA said that we should work on something like this:  CREATE TABLE Warehouse( filterId VARCHAR(20) PRIMARY KEY, active BOOLEAN DEFAULT 1, warehouseName VARCHAR(30) NOT NULL)   | FILTERID   | ACTIVE | WAREHOUSENAME | --------------------------------------- | 1.00       |      1 | N WAREHOUSE 1 | | 1.01       |      1 | ROOM 1        | | 1.02       |      1 | ROOM 2        | | 1.03       |      1 | ROOM 3        | | 1.04       |      1 | ROOM 4        | | 1.01.01    |      1 | SHELF 1       | | 1.01.02    |      1 | SHELF 2       | | 1.01.03    |      1 | SHELF 3       | | 1.01.04    |      1 | SHELF 4       | | 1.01.05    |      1 | SHELF 5       | | 1.01.06    |      1 | SHELF 6       | | 1.01.07    |      0 | SHELF 7       | | 1.01.01.01 |      1 | BOX 1         | | 1.01.01.02 |      0 | BOX 2         | | 1.01.01.03 |      1 | BOX 3         | | 1.01.01.04 |      1 | BOX 4         | ---------------------------------------   Which way should we follow?   On one hand we have a relationship between parentId and filterId; on the other we do not have any relationship, but it is easy to understand where does the entry belong.  Not all the warehouses are of the same level - that's what I mean by degree. They should be ordered like: For Customer A, 1 is parent of 1.1 and 1.2, 2 is parent of 2.1, 3 is parent of 3.1 and 4 is parent of 4.1 and 4.2 - but 1, 2, 3 and 4 are of the same level (1st level), and 1.1, 1.2, 2.1, 3.1, 4.1 and 4.2 are also of the same level (2nd level) but not of the same parents. If I'm standing at the equator, jump, and land 1 second later, the  Earth does NOT move 1000mph (or .28 miles per second) relative to me,  since my velocity while jumping is also 1000mph.   However, the Earth is moving in a circle (albeit a very large one),  while I, while jumping, am moving in a straight line.   How much do I move relative to my starting point because of this? I  realize it will be a miniscule amount, and not noticeable in practise,  but I'd be interested in the theoretical answer. Windows seems to have a length limit on file names when trying to delete, though it won't prevent those files from being created.  Our build process creates a number of temporary files (many build off of a WSDL) that run afoul of this limit.  Our ant script is somehow able to delete them when doing a clean, but sometimes I need to delete the workarea directory (where all the temp files go) without actually doing a full clean from ant.  This is the same errors , but the answers there don't really work for me as I'm dealing with a directory, not a file, and I don't always know what specific files or subdirectories are causing the problem.  And I'm trying to avoid any manual process (other than triggering a single command) to actually delete them.  If I try deleting the directory from Explorer I get the error   Cannot delete [file name]: The file name you specified is not valid or too long.   Specify a different file name   Trying Remove-Item in powershell gives the following error:  Remove-Item : The specified path, file name, or both are too long. The fully qualified file name must be less than 260 characters, and the directory name must be less than 248 characters. At line:1 char:12 + Remove-Item  &lt;&lt;&lt;&lt; -force -Recurse &lt;directory&gt;   Does anyone know of any tools or easy ways to get around this delete error without having to manually find the problem files and move/rename them? I've just upgraded from Ubuntu 18.04 to its newest LTS version - 20.04. While it comes with some interesting changes, the Desktop icon system was messed up in my opinion. When you hover the mouse cursor over the icons, you see a huge space marked around them that cannot be violated (as you can see in the image below) so that they need to be placed very far apart from each other.  18.04 allowed you to place icons much closer to each other and didn't have that marked space around them. This new way leaves much less space on the Desktop to organize large amounts of icons - including folders, files and shortcuts. Is there a way I can significantly reduce the size of icons and their "spaces" or go back to the old system of organizing files? On "Settings", there is a tool to change the size of Dock icons, but not of Desktop icons.  Also, every time I move or delete something, the Desktop "flashes" and the icons seem to rearrange themselves automatically, nothing of which happened in 18.04. I also can't move anything directly to the Desktop; I need to move to the Desktop folder on Nautilus. This makes me start to think about downgrading Ubuntu back to 18.04.