After I installed 14.04 desktop, launcher on left side is missing After I installed the ubuntu 14.04 desktop, the unity launcher on left side is not appearing. I have confirmed that unity is installed.
Unity doesn't load, no Launcher, no Dash appears When I login, nothing happens.   I am presented with my desktop wallpaper.    No Dash, no Launcher, nothing.
Uniform convergence of alternating series Generate all combinations from multiple lists In Ubuntu 18.04, I can create a file as one user in /tmp, and write to it as user root (despite the sticky bit being set on /tmp). In Ubuntu 20.04, I get a Permission Denied error as user root. Ubuntu 18.04: # As user &quot;ubuntu&quot;: touch /tmp/tmplock  # As user &quot;root&quot;: echo &quot;foo&quot; &gt; /tmp/tmplock  cat /tmp/tmplock # Outputs &quot;foo&quot;  ls -lah /tmp drwxrwxrwt 32 root   root    20K Jun 16 18:36 . -rw-rw-r--  1 ubuntu ubuntu    4 Jun 16 18:36 tmplock  Ubuntu 20.04: # As user &quot;ubuntu&quot;: touch /tmp/tmplock  # As user &quot;root&quot;: echo &quot;foo&quot; &gt; /tmp/tmplock # Outputs: bash: /tmp/tmplock: Permission denied  ls -lah /tmp drwxrwxrwt 12 root   root   4.0K Jun 16 18:15 . -rw-rw-r--  1 ubuntu ubuntu    0 Jun 16 18:14 tmplock  I can't find any information on if this is related to the sticky bit, or an underlying Linux kernel change, or anything. Does anyone know what can explain the change in behavior? RECENTLY ON THE ANDROID SITE WE GOT  WRITTEN IN ALL CAPS.  THIS WAS SURPRISING TO ME, SINCE I ASSUMED IT WOULD HAVE BEEN CAUGHT BY THE QUALITY FILTER &mdash; BESIDES BEING INDICATIVE OF OTHER POST QUALITY ISSUES, IT'S AWFUL TO LOOK AT AND REQUIRES A LARGE AMOUNT OF EDITING TO FIX (EVEN IF YOU RUN IT THROUGH TOLOWER() FIRST).  WE ALL KNOW THAT CAPS LOCK IS , BUT STILL: CAN WE BLOCK THESE QUESTIONS?    RICK  RICK  OH MAN THAT STUFF JACOB G  IS COMEDY GOLD  RIIICK     Note to editors: This post looks exactly like it is supposed to look, as an example of a question in all-caps. Please do not replace the uppercase letters with lowercase. What is the meaning of the integral of position? Jerk, $j(t)=\dddot x(t)$, acceleration, $a(t)=\ddot x(t)$ and velocity, $v(t)=\dot x(t)$ are derivatives of position, $x(t)$. What is the meaning of the integral of position?  For example, one could write  $$\int x \mathrm{d}t = \int x \frac{\mathrm{d}t}{\mathrm{d}x}\mathrm{d}x = \int x\frac{1}{v} \mathrm{d}x$$  which reminds the equation for . I've connected a USB to Serial bridge dongle, and running dmesg | grep tty outputted the following:  [    0.000000] console [tty0] enabled [603199.380677] usb 2-2: cp210x converter now attached to ttyUSB0   So now I'm trying to write to it as per  by running the following:  cat hello.txt &gt; /dev/ttyUSB0   and   sudo cat hello.txt &gt; /dev/ttyUSB0   But both result in the following error:  bash: /dev/ttyUSB0: Permission denied   What am I doing wrong?  Thanks Intuition for Rayleigh PDF We have ground-truth data $\mathbf{x}^* = (0,0)^T \in \mathbb{R}^{2}$. Furthermore, we have $N$ measurements $\mathbf{x}_i \in \mathbb{R}^{2}, i\in \{1,\ldots,N\}$. We calculate the $N$ error vectors $\mathbf{e}_i = \mathbf{x}_i - \mathbf{x}^*$. We assume that the two components of $\mathbf{e}_i = (e_{x,i}, e_{y,i})^T $ are independent of each other and normally distributed with equal mean $\mathbf{\mu} = (0,0)^T$ and variance $\sigma^2$. The absolute errors $e_i = \sqrt {e_{x,i}^2 + {e}_{y,i}^2} $ follow a Rayleigh distribution, is that correct?  The probability density function (PDF) of the Rayleigh function is zero at a value of zero. Why is this the case (intuitively)? I would assume that our errors should most likely be 0 (i.e. PDF should be highest at 0)... How do you use plural or singular form of an adjective? So I was taught that you should almost always use singular form of an adjective instead of plural form. But recently, I've seen people using plural form and it sounds quite weird and I don't know if it is correct.  For example,   "Salary tax" instead of "Salaries tax" "Office supplies" instead of "Offices supplies" "Product demo" instead of "Product demo"   In the above cases, the word "Salary" is used as an adjective to describe the type of "tax", so it will be in singular form. But I saw people using salaries tax and not sure if it is grammatical.  So my question is if there are any general rules on how to use the singular/plural form of an adjective? When is the new ball due for all forms of cricket? Is there a standard time fixed in Test, ODI and T20 formats of Cricket, when a fielding side captain can ask for a new ball?  If the captain of the fielding side doesn't ask for a new ball, will he be forced to have it mandatorily after a certain point by the match umpires? I did an upgrade today to the latest version of ubuntu. Everything looked good and fine only for me to discover that I cannot find my applications after clicking the 'Show Applications' icon. The same applies when I search for an application in the search bar, I do not see it. It shows me an endless search.  These are the screenshot images of the problem:      In the meantime, I access my applications from the menu at the top bar and also use the terminal to run applications with CLI. Problem with a sequence with multiple integrals Regarding the advanced edition of FTL:  If all of your crew dies but you have a cloning bay on your vessel, is it immediately game over, or does the cloning bay prevent that?  Is the game smart enough to know that a damaged cloning bay and a fully dead crew means you cannot recover, but a functional one (even if temporarily without power) could revive your crew?  Also, does this answer differ between hostile ships and your own ship?  (That is, do you get to capture and loot enemy vessels that have all dead crew but have a functional cloning bay?) Noetherian property for exact sequence Let $0 \to M' \xrightarrow{\alpha} M \xrightarrow{\beta} M'' \to 0$ be an exact sequence of $A$-modules. Then $M$ is Noetherian is equivalent to $M'$ and $M''$ are Noetherian.  For the ''$\Leftarrow$'' case:  I guess if we let $(L_n)_{n\geq 1}$ be an ascending chain of submodules of $M$, then $(\alpha ^{-1}(L_n))_{n\geq 1}$ is a chain in $M'$, and $(\beta(L_n))_{n\geq 1}$ is a chain in  $M''$. For large $n$ both these chains are stationary. Then why we know the chain $(L_n)$ is stationary?   Thanks! Which one is correct, or are both of them fine?    "It would take the average person 10 days to read this novel"    Or    "It would take an average person 10 days to read this novel" I applied for a 90-day visa and got a long-term visit, single-entry tourist visa. The date given is 09-March-2015, and it's valid until 07-May-2015.  My agent says the 7th is the latest date I can travel to Dubai; once I enter I need to count 90 days. I entered on the 10th of March.    Is it true, or where can I get it checked?    Can I stay for another month, or do I need to leave before the 7th of May? Find the sum of the series $\sum \frac{1}{n(n+1)(n+2)}$ Best way to implement keyboard shortcuts in a Windows Forms application? I'm looking for a best way to implement common Windows keyboard shortcuts (for example Ctrl+F, Ctrl+N) in my  application in C#.  The application has a main form which hosts many child forms (one at a time). When a user hits Ctrl+F, I'd like to show a custom search form. The search form would depend on the current open child form in the application.  I was thinking of using something like this in the ChildForm_KeyDown event:     if (e.KeyCode == Keys.F &amp;&amp; Control.ModifierKeys == Keys.Control)         // Show search form   But this doesn't work. The event doesn't even fire when you press a key. What is the solution? How to redirect output to a file and stdout Let $a, b, \&amp; \, m$ be integers. Prove that if $2a + 3b \geq 12m + 1$, then $a \geq 3m + 1$ or $b \geq 2m + 1$.   My Attempt: I don't conceive apace how to contrive, from the one inequality in the antecedent, the two inequalities in the consequent. So a proof by contraposition may be more facile. The contrapositive is: $\text{If }  \color{Green}{a &lt; 3m + 1} \; \&amp; \; \color{#0073CF}{b &lt; 2m + 1}, \text{ then } 2a + 3b &lt; 12m + 1 \tag{*}.$  From $(*)$, $\color{Green}{2a} + \color{#0073CF}{3b} &lt; \color{Green}{6m + 2} \; + \;\color{#0073CF}{6m + 3} = 12m +5$. But this doesn't prove $(*)$.     Given Solution:  Assume that $a &lt; 3m+1$ and $b &lt; 2m+1.$ Since a and b are integers, $a ≤ 3m$ and $b ≤ 2m.$ Therefore, $2a + 3b ≤ 2(3m) + 3(2m) = 12m &lt; 12m+ 1,$ as desired. $\blacksquare$   What went wrong in my attempt? I understand the given solution but I persisted with the more natural and direct green and blue, instead of deviating to weak inequalities. Shouldn't both solutions work?  Source: Problem 4.19 on P102 (related to P90, Result 4.8) of Mathematical Proofs, 2nd ed by Chartrand et al.    $\large{\text{Supplement to Cameron Buie and pritam's Answers :}}$  What overriding, catholic lessons can be extrapolated from this example to generalise about inequalities?   Moreover, in order to circumvent the problem here (ie the loss of information from the weaker inequalities), should I always start with the strictest inequality? If so, should I always rework any weak inequality into the equivalent strict inequality?   For example, define $r \in \mathbb{R} $ and $n \in \mathbb{Z}$ and $g(...) \neq h(...)$. Then $ f(r) &lt; h(r) \require{enclose}      \enclose{updiagonalstrike}{\iff} f(r) \leq g(r).$ But $ f(n) &lt; h(n) \text{ MAY OR MAY NOT }\iff f(n) \leq g(n).$ In linear regression, each predicted value is assumed to have been picked from a normal distribution of possible values. See below.  But why is each predicted value assumed to have come from a normal distribution? How does linear regression use this assumption? What if possible values are not normally distributed?