Using a comma before "and" in a list I am confused as to when commas are supposed to be used before the conjunction and.    answers it but I am still a bit confused.   For instance the following two sentences:         I am going to buy apples, oranges, and bananas at the store.    I am going to buy apples, oranges and bananas at the store.       Which of the above sentences is the correct usage of a comma?
Should I put a comma before the last item in a list? Should I put a comma before the last item in a list?     I would like crackers, cheese and some soda.   I would like crackers, cheese, and some soda.
Miraak is stealing all my dragon souls What is the likelihood of ever discovering the graviton? How would one look for and confirm existence of a graviton?  Someone was speaking to me about perhaps one day discovering the graviton, but to me it seems unlikely, although I'm young and essentially quite naive, so am coming to you physicists to ask    What actually is the likelihood of finding it?  How would we find it? I uninstalled my wine, and installed a higher version of wine by compiling source.  However when I run an exe executable (whose path is in $PATH), it doesn't work as it used to:  $  PDFXCview.exe     run-detectors: unable to find an interpreter for /home/tim/program_files/document/pdfxchange_portable/PDFXCview.exe   I am not sure why I was able to run this executable directly before I uninstalled my old wine and installed the new one. How can I make $  PDFXCview.exe work now?  Note:  $ wine /home/tim/program_files/document/pdfxchange_portable/PDFXCview.exe   will work.   $ wine PDFXCview.exe   wine: cannot find L"C:\\windows\\system32\\PDFXCview.exe"   doesn't work. Note that the path of PDFXCview.exe is still in $PATH  Thanks. Compiling the following code and got the error of type illegal.  int main() {     // Compilation error - switch expression of type illegal     switch(std::string("raj"))     {     case"sda":     } }   You cannot use string in either switch or case. Why? Is there any solution that works nicely to support logic similar to switch on strings? sum of noncentral Chi-square random variables I need to find the distribution of the random variable  $$Y=\sum_{i=1}^{n}(X_i)^2$$ where $X_i\sim{\cal{N}}(\mu_i,\sigma^2_i)$ and all $X_i$s are independent. I know that it is possible to first find the product of all moment generating functions for $X_i$s, and then transform back to obtain $Y$'s distribution. However, I wonder whether there is a general form for $Y$ like the Gaussian case: we know the sum of independent Gaussian is still a Gaussian, and thus we only need to know the summed mean and summed variance.   How about all $\sigma^2_i=\sigma^2$? Will this condition make a general solution? I’m running Ubuntu 14.04. When I run:   sudo add-apt-repository ppa:ubuntu-wine/ppa   I get the following error:  sudo: add-apt-repository: command not found   I tried to run  sudo apt-get install software-properties-common   but it shows:  software-properties-common is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 1 not upgraded. Is there a word in English to qualify the highest-ranked student in a class in a year?  We are talking here about higher education, especially in the context of curricula that keep a given set of students over the course of several years, being ranked at the end of each year, possibly with competitive admission for the following year. The ranking is a weighted average of all marks obtained over the year.  I am looking for a single word, or expression, to quickly designate the one student with the highest ranking. If there is no such thing in English, then let's try to get the most concise and idiomatic definition.  In all cases, it is not emotionally connoted, i.e. not pejorative nor bragging.  For French speakers: I am looking for the translation of “major de promotion”.    EDIT: additional, not as much of a pure “word request” question: is this anything you should mention on a curriculum vitæ in the English-speaking world? If so, please mention whether the given word is appropriate for such a use&nbsp;&nbsp;:) The Lorentz force on a charged particle is perpendicular to the particle's velocity and the magnetic field it's moving through. This is obvious from the equation:  $$ \mathbf{F} = q\mathbf{v} \times \mathbf{B} $$  Is there an intuitive explanation for this behavior? Every explanation I've seen simply points at the equation and leaves it at that.  I can accept mathematically why $\mathbf{F}$ will be perpendicular to $\mathbf{v}$ and $\mathbf{B}$ (assuming the equation is correct, which it is of course). But that doesn't help me picture what's fundamentally going on.  Trying to create an analogy with common experiences seems useless; if I were running north through a west-flowing "field" of some sort, I wouldn't expect to suddenly go flying into the sky.  I'm hoping there's a way to visualize the reason for this behavior without a deep understanding of advanced theory. Unfortunately, my searching for an explanation makes it seem like something one just has to accept as bizarre until several more years of study. why don't we define vector multiplication component-wise? I was just wondering why we don't ever define multiplication of vectors as individual component multiplication.  That is, why doesn't anybody ever define $\langle a_1,b_1 \rangle \cdot \langle a_2,b_2 \rangle$ to be $\langle a_1a_2, b_1b_2 \rangle$?  Is the resulting vector just not geometrically interesting? Clear item with custom name? Fuzzy string search library in Java Mount cifs Network Drive: write permissions and chown I have access to a cifs network drive. When I mount it under my OSX machine, I can read and write from and to it.   When I mount the drive in ubuntu, using:  sudo mount -t cifs -o username=${USER},password=${PASSWORD} //server-address/folder /mount/path/on/ubuntu   I am not able to write to the network drive, but I can read from it. I have checked the permissions and owner of the mount folder, they look like:  4.0K drwxr-xr-x  4 root root    0 Nov 12  2010 Mounted_folder   I cannot change the owner, because I get the error:  chown: changing ownership of `/Volumes/Mounted_folder': Not a directory   When I descend deeper into the network drive, and change the ownership there, I get the error that I have no permission to change the folder´s owner.  What should I do to activate my write permission? Index of the center of a group in the group is not a prime number The question is to prove index of $Z(G)$ in $G$ is not a prime number.    We know that $|G:Z(G)|=|G:C_G (x)||C_G (x):Z(G)|$ where $C_G (x)$ means centralizer of $x \in G$  I want to mention that we do not want to use $G⁄Z(G)$ theorem.   We may assume that $|G:Z(G)|=p$ where $p$ is a prime. Does the order of declaration matter in Java/C#? How can I tell if a CVE has been fixed in Ubuntu's repositories? Today a couple of buffer overflows in NTP were announced , . It looks like updating my system to fix these issues is in order.   How can I find out if they have been fixed in the Ubuntu repositories, such that if I were to run:   sudo apt-get update sudo apt-get upgrade   then the fix would get installed and the vulnerability closed?   Edit: The selected answer specifically addresses the question of how to identify if a given CVE has been fixed or not, "Does Ubuntu generally post timely security updates?"  is certainly related but not identical About an hour ago, from my account, an inappropriate message was posted as a reply to a Stack Overflow question.  I have noticed it, because I started getting downvotes. To my understanding my Gmail account wasn't compromised (I reviewed my account security settings and login history). I am from a secure WPA2 connection. I cannot find enough information on how to investigate this. Although I changed my passwords everywhere, I still seem confused and I would like to ask how to investigate this issue myself. Avoiding copy of objects with the "return" statement How do you format the day of the month to say "11th", "21st" or "23rd" (ordinal indicator)? Newtonian mechanics: massless particles Nullable type issue with ?: Conditional Operator Could someone explain why this works in C#.NET 2.0:      Nullable&lt;DateTime&gt; foo;     if (true)         foo = null;     else         foo = new DateTime(0);   ...but this doesn't:      Nullable&lt;DateTime&gt; foo;     foo = true ? null : new DateTime(0);   The latter form gives me an compile error "Type of conditional expression cannot be determined because there is no implicit conversion between '&lt;null&gt;' and 'System.DateTime'."  Not that I can't use the former, but the second style is more consistent with the rest of my code.