smelling something Dangerous about update I am attaching two screen shots, self explained. Why do an update asking something regarding my boot sector? isn't dangerous?
What is the safest way to clean up /boot partition? I have 200 MB assigned for the /boot partition.  Whenever I try to update the kernel, I receive an error message that basically states /boot is full.  What can I do to cleanup /boot and remove/backup the older kernels?
Removal of statistically significant intercept term increases $R^2$ in linear model In a simple linear model with a single explanatory variable,  $\alpha_i = \beta_0 + \beta_1 \delta_i + \epsilon_i$  I find that removing the intercept term improves the fit greatly (value of $R^2$ goes from 0.3 to 0.9). However, the intercept term appears to be statistically significant.  With intercept:   Call: lm(formula = alpha ~ delta, data = cf)  Residuals:      Min       1Q   Median       3Q      Max  -0.72138 -0.15619 -0.03744  0.14189  0.70305   Coefficients:             Estimate Std. Error t value Pr(&gt;|t|)     (Intercept)  0.48408    0.05397    8.97   &lt;2e-16 *** delta        0.46112    0.04595   10.04   &lt;2e-16 *** --- Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1   Residual standard error: 0.2435 on 218 degrees of freedom Multiple R-squared: 0.316,    Adjusted R-squared: 0.3129  F-statistic: 100.7 on 1 and 218 DF,  p-value: &lt; 2.2e-16    Without intercept:   Call: lm(formula = alpha ~ 0 + delta, data = cf)  Residuals:      Min       1Q   Median       3Q      Max  -0.92474 -0.15021  0.05114  0.21078  0.85480   Coefficients:       Estimate Std. Error t value Pr(&gt;|t|)     delta  0.85374    0.01632   52.33   &lt;2e-16 *** --- Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1   Residual standard error: 0.2842 on 219 degrees of freedom Multiple R-squared: 0.9259,   Adjusted R-squared: 0.9256  F-statistic:  2738 on 1 and 219 DF,  p-value: &lt; 2.2e-16    How would you interpret these results? Should an intercept term be included in the model or not?  Edit  Here's the residual sums of squares:  RSS(with intercept) = 12.92305 RSS(without intercept) = 17.69277 So I have a program written in C++.  It can tell me how long it took to do all the calculations and it does a lot of quite heavy, multi-threaded calculation.   I've just noticed that if I run the program on the exact same machine, it takes around 20-21 seconds to do all the calculations if started from the TTY, and only about 0.2 seconds if I start it from GNOME terminal.  What is causing that? It's literally the exact same file on the same machine. Find My iPhone Email Notification Is the email notification from Apple that your device has been tracked using Find My iPhone a new feature? The value of $\lim_{n \to \infty}\int_{0}^{1}nx^ne^{x^2}dx$ is _____ I tried by taking the odd $n$ values as in that case, the integral I suppose was easier to calculate. So, denote $I_n=n\int_{0}^{1}e^{x^2}x^ndx$, then we have : $I_1=\frac{e-1}{2},\\I_3=\frac{3}{2},\\I_5=5(\frac{e}{2}-1),\\I_7=7(3-e)$ Then I tried calculating (random) values using calculator as integration was getting cumbersome. $I_{31}=2.488$, $I_{51}=2.57$. I do not see any kind of recurrence so that I can find a general term for odd $n$. I also tried the method given . The idea was that since integral doesn't depend on $n$ considering $I(n)=\int_{0}^{1}e^{x^2}x^ndx$, then $I'(n)=\int_{0}^{1}x^n\ln(x)e^{x^2}dx$, but this also doesn't lead me to any conclusion as well. I believe I couldn't get to a proper approach to tackle this question. Can someone please help with the idea that involves in solving these type of questions? I'm reading .     The graph of $f: A \rightarrow B$ is the subset of $A × B$ consisting   of all ordered pairs $(a, b)$ with $f (a) = b$. If $A$ happens to be   $B^n$ for some $n ∈ N$, then we say that $f$ is a function on $B$ and   $n$ is the arity of $f$.   I don't understand the notation for the exponent of a set, I'm aware of what  is, it's the number of arguments or operands the function takes. I'm just not so sure if I can assume that a set with an exponent such as in $B^n$ means that a function has two operands.  I know the question may be too naive and perhapes the answer is the one I suggested and it's right in front of my face, I'm just searching for a confirmation or the negation of it. Thanks. Node.JS Not working on the internet How does Spider-Man climb walls? Restrictive vs Non-restrictive Relative Clause Can you tell me the difference in the meaning of the two sentences below?  As a defining relative clause.     The location which was called Central Park was a park in New York.    As a non-defining relative clause.     The location, which was called Central Park, was a park in New York. Intuition about Herbrand Models. I'm having trouble understanding how Herbrand models work. I feel like there is a bigger picture to it which I'm not understanding. Why does every satisfiable first order formula have a herbrand model at all ? Can I somehow construct a Herbrand model from a normal model ? My book also says that : a formula is unsatisfiable iff the Herbrand expansion is unsatisfiable. The book I'm using &quot;Mathematical Logic for computer science by Mordechai Ben-Ari&quot; has all the proofs of the above but its not very intuitive to me. Could somebody share their point of view? Starters on Stack Overflow tend to lose interest as soon as their first question starts getting downvotes. Their first question also sometimes gets closed because it was either not framed properly or it missed some very common things.  There should be way to cope with this for instance give some starter bonuses to new users. How do I exclude plugins from getting automatically updated? There is an opt-in filter that allows all plugins on my site to receive automatic updates:  add_filter( 'auto_update_plugin', '__return_true' );  I like this feature, but I don't want all my plugins to be updated automatically. How can I allow some plugins to be updated automatically, while excluding those I want to do manually? GRUB doesn't show Windows 10 Whenever I boot into my system, Linux directly boots. If I press shift, GRUB shows only Linux, not Windows. Here are results of fdisk and update-grub. I think I have installed Linux the wrong way.  $ fdisk WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted.   Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x00000000     Device Boot      Start         End      Blocks   Id  System /dev/sda1               1  1953525167   976762583+  ee  GPT Partition 1 does not start on physical sector boundary.  $ update-grub Generating grub configuration file ... Warning: Setting GRUB_TIMEOUT to a non-zero value when GRUB_HIDDEN_TIMEOUT is set is no longer supported. Found linux image: /boot/vmlinuz-3.19.0-32-generic Found initrd image: /boot/initrd.img-3.19.0-32-generic Found memtest86+ image: /boot/memtest86+.elf Found memtest86+ image: /boot/memtest86+.bin   No volume groups found done What does “” exactly mean in “echo  temp.txt”? Is my US visa still valid after change in name? Random Gaussian Variables Is there a class in the standard library of .NET that gives me the functionality to create random variables that follow Gaussian distribution? The link here:  shows that $\max(a,b)=\frac{a+b+|a-b|}{2}$.      Is it true that $\max(|a|,|b|)=\frac{1}{2}(|a|+|b|)$? Accessing inherited variable from templated parent class Consider the following code:  template&lt;class T&gt; class Foo { public:   Foo() { a = 1; }  protected:   int a; };  template&lt;class T&gt; class Bar : public Foo&lt;T&gt; { public:   Bar() { b = 4; };    int Perna(int u);  protected:   int b;  };  template&lt;class T&gt; int Bar&lt;T&gt;::Perna(int u)  {    int c = Foo&lt;T&gt;::a * 4; // This works   return (a + b) * u;    // This doesn't }   g++ 3.4.6, 4.3.2 and 4.1.2 give error   test.cpp: In member function `int Bar&lt;T&gt;::Perna(int)': test.cpp:25: error: `a' was not declared in this scope   g++ 2.96 and MSVC 6, 7, 7.1, 8 and 9 accept it, as do (at least) older Intel and SGI c++ compilers.   Do the new Gnu C++ compiler obey the standard or not? If they do, what is the rationale behind that inheriting class is not able to see a protected inherited member variable?  Also, if there's  int A() { return a; }    in Foo, I get error  test.cpp:25: error: there are no arguments to A that depend on a template parameter, so a declaration of A must be available test.cpp:25: error: (if you use -fpermissiveâ, G++ will accept your code, but allowing the use of an undeclared name is deprecated)   when I try to use it in a member function of Bar. I find that curious as well: Bar inherits Foo, so I think it's obvious that A() in scope of Bar is Foo::A(). Does casting a spell from an item allow you to apply class abilities that are used when casting a spell? This question is updated to request additional answers and details in light of information now available in the Dungeon Master's Guide. In the released DM basic rules, Lost Mine of Phandelver, Hoard of the Dragon Queen, and the DMG teaser there are wands, staves, and rings that you can use to cast spells.  Do abilities that trigger from casting a spell activate when casting a spell from an item?  Can the character modify the spell using class abilities when casting a spell from an item?   Examples include:  An abjurer Wizard's arcane ward recovering hit points from a Dispel Magic cast from a Ring of Spell Storing  A sorcerer using Twinned Spell on a ray of enfeeblement from a Staff of Power  An evocation wizard using Sculpt Spell on a fireball from a Wand of Fireballs.   Now that the DMG is out we have some clearer rules on casting spells from items (DMG p. 141):  Some magic items allow you to cast a spell from the item.  The spell is cast at the lowest possible spell level, doesn't expend any spell slots, and requires no components, unless the item's description says otherwise  The spell uses its normal casting time, range and duration, and the user of the item must concentrate if the spell requires concentration. A magic item, such as certain staffs, may require you to use your own spellcasting ability when you cast a spell from the item.  Does whether or not you can apply class abilities to the casting of the spell depend whether the item uses the user's own spellcasting ability (such as the Staff of Fire) versus an item that comes with a fixed spellcasting ability built-in (such as the Wand of Fireballs)? Does it matter if it's something that triggers more or less automatically like Arcane Ward, versus something you have to control, like Careful Spell? SSH and home directory permissions Run a command before & after ubuntu apt upgrade & unattended-upgrades