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After plain installation of Ubuntu 16.04 LTS gnome-software doesn't work. It has opened once with GUI, but installation of Unity Tweak Tool didn't finish.  When starting again, GUI doesn't come up. When opening from terminal, a warning appears, but the application GUI doesn't open.  $ gnome-software (gnome-software:7052): Gs-WARNING: failed to open plugin /usr/lib/gs-plugins-9/libgs_plugin_xdg_app_reviews.so: /usr/lib/gs-plugins-9/libgs_plugin_xdg_app_reviews.so: cannot open shared object file: No such file or directory   Does anybody have same experience, and eventually, a solution?    According to the recommendation:  $ dpkg-query -S /usr/lib/gs-plugins-9/libgs_plugin_xdg_app_reviews.so gnome-software: /usr/lib/gs-plugins-9/libgs_plugin_xdg_app_reviews.so   Proposed reinstall of gnome-software did not help.    As workaround, use Synaptic Package manager and command line. List of blogs to learn more about Ubuntu Add blogs and websites that are useful in the quest to know/learn more about Ubuntu.  One blog per answer, please - you can vote answers up/down as you feel appropriate. If you feel the blog is biased towards or is good for particular tasks, please mention them. I encountered the integral $$\int_0^1 \frac{\log \left(1-x^2\right) \sin ^{-1}(x)^2}{x^2} \, dx = -0.9393323982...$$ while researching the evaluation of harmonic sums. Mathematica 11 is not able to evaluate this integral, and is not able to evaluate the underlying indefinite integral.  I considered using the Maclaurin series for the expression $\sin ^{-1}(x)^2$ to evaluate this integral. Using this Maclaurin series, it is easily seen that the problem of evaluating the above integral is equivalent to the problem of evaluating the series $$\sum _{n=1}^{\infty } \frac{2^{2 n-1} H_{n-\frac{1}{2}}}{(1-2 n) n^2 \binom{2 n}{n}}=-0.9393323982...$$ which Mathematica 11 is not able to evaluate directly.  I also considered using the Maclaurin series for the expression $\log \left(1-x^2\right)$ to evaluate the above integral. Using this Macluarin series, it is easily seen that this integral is equal to $$\frac{1}{4} \left(16 \pi  C-\pi ^3-\pi ^2 \log (4)\right)+\sum _{n=1}^{\infty } \frac{\, _3F_2\left(\frac{1}{2},\frac{1}{2},1;\frac{3}{2},n+1;1\right)}{n^2-2 n^3}=-0.939332...,$$ but Mathematica is unable to evaluate the above infinite series.  What is a closed-form evaluation of $\int_0^1 \frac{\log \left(1-x^2\right) \sin ^{-1}(x)^2}{x^2} \, dx$? What techniques can be applied to evaluate this definite integral? True or False: there is a space $X$ such that $S^1$ is homeomorphic to $X\times X$ I had an exam this morning, one of the questions asked about the truth of the statement      There is a space $X$ such that $S^1$ is homeomorphic to $X\times X$.   I said that this was false and this was my reasoning... was I correct? (Note, an earlier part of the question asked me to prove $\pi_1(Y\times Z)=\pi_1(Y)\times\pi_1(Z)$, I took this as a hint.)  Suppose for the sake of contradiction that such an $X$ exists. Then $\Bbb{Z}\cong G\times G$ where $G\cong\pi_1(X)$. Let $\Phi$ be the isomorphism.  Let $\Phi(1)=(g_1,g_2)\in G\times G$. Then at least one of $g_1,g_2$ is nonzero, since $\Phi(0)=(0,0)$ (the identity on $G\times G$, and $\Phi$ is injective). Without loss of generality $g_1\ne 0$. Then which element $n\in\Bbb{Z}$ has $\Phi(n)=(kg_1,0)$? Since $$kg_1=\underbrace{g_1+\dots +g_1}_k\in G,$$ and $\Phi$ is surjective, such an $n$ should exist. But this is not possible since $\Phi(n)=(kg_1,0)$ implies (since $\Phi$ is a homomorphism) that $kg_1=ng_1$ and $ng_2=0$, and since $k$ was arbitrary and this need not hold if $k\ne 0$. In the PGF/TikZ manual, sometimes I see the option right of=somenode instead of right=of somenode. They look very similar, but the effects are different.  The distance between nodes positioned with the latter option is boundary-to-boundary, as stated in the manual. However, with the first option, it seems that the distance is shorter. I couldn't find any explanation of the first option in the manual.  My question is: what is the difference between the two options? Is there any explanation in the manual that I missed? Why is Android refusing to resolve DNS records pointing to internal IP addresses? How to preserve non-ASCII characters in ogr2ogr import? I applied to a program that I had been striving for in my undergrad, at a top school, but I've since felt overwhelmed with the thought of going this year. I think I should have waited until I was absolutely sure I could handle grad school emotionally and financially. I am so anxious now, thinking I've ruined my opportunity with this school if I don't go.   I am seriously considering withdrawing my application, but I'm very worried about how it might hurt me in the future when I reapply.  Otherwise I may have to decline if I am accepted and reapply. Efficient way to find $[\mathbb{Q}(\sqrt{5}, \sqrt{3}, \sqrt{2}): \mathbb{Q}(\sqrt{3}, \sqrt{2})]$ I want to show rigorously that this is 2. I'm sure there's a faster way than by trying to see if $\sqrt{5} = a + b \sqrt{2} + c \sqrt{3} + d \sqrt{6}$ (linear combination of the basis elements for $\mathbb{Q}(\sqrt{3}, \sqrt{2})$). I'm just not sure what. I'd like to be able to decompose a concave mesh into a set of convex meshes for 2 reasons:   Transparent rendering Physics shapes   Is there an algorithm that takes a set of triangles (concave) as input and outputs a number of sets of triangles (convex)?  I'd like it to not fill in the holes between parts of the original mesh.  I've already come across a small idea: find all the concave edges, and split the meshes along the edge loops.  Am I on the right track?  How could I implement this? How can I do a brute force (ciphertext only) attack on an CBC-encrypted message? Given a CBC ciphertext and IV, how can I find the encryption key?  We are limited with an 8 chars key, each char in the range of [a..h], so I can generate every possible key (these are only $8^8 = 2^{24}$ (about 4 million) different possible keys).  How would I go about finding the correct one though? fetching list of friends using facebook 2.0 I am trying to implement  using additive ElGamal.  I am trying to run the full protocol mentioned in Section 3.4 on the following inputs:   $p = 17$ (prime) $g = 6$ (generator) $x = 5$ (private key) $k = g^x \pmod p = 6^5 \pmod{17} = 7$ (public key)   Suppose the clients inputs are 1, 2. Then $P(x) = (x-1)(x-2) = x^2-3x+2$, and therefore the coeffiecients to encrypt are $(1, -3, 2)$. I chose $y = 10$ and so the encrypted values are:   $1$ becomes $(15,12)$ $-3$ becomes $(15, 1)$ $2$  becomes $(15, 4)$.   The Server Side Input Set $S=\{1\}$ and the random value $r0$ corresponding to $\{1\}$ is $r_0=2$.    With the above problem in context, I have some questions:   What does P 0,j refer to in Step 7. Can you please give an example? In Step 8, suddenly variable i is introduced along with j. What does i, j, refer to? In Step 8, ENC() function has a ; in between. How do we interpret ENC(a;b)? Many apps are missing from Ubuntu Software app I tried to enable additional repositories according to the instructions from , however my Ubuntu Software app is still missing a lot of popular apps. Is there anything I'm missing?  Ubuntu 16.10 Ubuntu Software app 3.20.1 Can massive damage knock out rather than causing instant death? Suppose, as happened last night, a character intends to subdue rather than kill an opponent. She made a melee attack, hit, declared her intent to knock out. The damage roll was enough to reduce the opponent to zero and the remaining damage exceeded the opponent's maximum HP. Now we would seem to have two rules invoked:  Instant Death. Massive damage can kill you instantly. When damage reduces you to 0 hit points and there is damage remaining, you die if the remaining damage equals or exceeds your hit point maximum. (PHB p.197) Knocking a Creature Out. When an attacker reduces a creature to 0 hit points with a melee attack, the attacker can knock the creature out. The attacker can make this choice the instant the damage is dealt. The creature falls unconscious and is stable. (PHB p.198)  So which rule takes precedence? Or is it neither? Ubuntu desktop suddenly points to home folder Can cited works hold grammatical positions in sentences? Though I read this style quite often, I was recently told unambiguously by a reviewer that I was NOT supposed to use citations "as if they are objects in a sentence."  The following sentence is an example of what the reviewer considered unacceptable:       We analyzed the data using the Wilmerding method, guided by [12].   The references section might include the following:      [12] Smith, D., Marshawn, J., &amp; Devenshaw, A. 2011. Techniques and   Procedures for Applying the Wilmerding Method.  Prince Publications,   Inc, New York, NY.   The Wilmerding method1 is not a step-by-step algorithm that can be precisely followed as if by a machine, and thus [12] does not provide a step-by-step algorithmic description but rather guidance for using  the method. [12] is a relatively slim but authoritative textbook about how to use the Wilmerding method.  Within this question, for the purpose of discussion, I have intentionally put [12] in grammatical positions where it's an important element of the sentence and the sentence would make less sense without the reference.  Sometimes that seems to be the most efficient way to communicate the intended message.  Is using a reference as a grammatical sentence element like this OK?   Why might this not be considered acceptable?   Should I be rewording those sentences?  Is it enough of a violation to be worth passing the note on to authors of papers I review?   I considered posting this on  but it seems more specific to academia than general English usage, and the comment came from a content reviewer rather than a copy editor.   is related but it seems to be more about when to put authors names' in vs. outside of the parentheses in an APA-like style.   The numbered citation style (as opposed to following APA, for example) is required by the venue.  1: Fictionalized for the purpose of this discussion Can you explain briefly the main concepts and command line tools used to manage file permissions? How do I remove the space between inline/inline-block elements? How does item level and rarity affect the possible attributes?