It is well known that every fundamental particle has a corresponding antiparticle, and that  – except for particles which are their own antiparticle – for practically every pair of particles and antiparticles, one type of particle predominates. We call this particle matter, and its antiparticle is considered to be antimatter.  However, is there any intrinsic difference between matter and antimatter, or are these terms defined based on nothing more than the balance that we so happened to end up with? For example, is there any reason that we should place an up quark and a charm quark in the same category, and not an up quark and a charm antiquark? Is there any reason we should group together up quarks and electrons rather than up quarks and positrons?
The identification of an electron as a particle and the positron as an antiparticle is a matter of convention. We see lots of electrons around us so they become the normal particle and the rare and unusual positrons become the .  My question is, when you have made the choice of the electron and positron as particle and anti-particle does this automatically identify every other particle (every other fermion?) as normal or anti?  For example the proton is a particle, or rather the quarks inside are. By considering the interactions of an electron with a quark inside a proton can we find something, e.g. a conserved quantity, that naturally identifies that quark as a particle rather than an antiparticle? Or do we also just have to extend our convention so say that a proton is a particle rather than an antiparticle? To complete the family I guess the same question would apply to the neutrinos.
Notify users of a question they closed being edited or nominated for reopening on the premise that it "wasn't getting any attention" and now it has gotten a bunch of helpful answers which all help me in some ways making it impossible for me to decide which one to award the bounty to.  Shouldn't there be an option to award the bounty equally among selected answerers, especially in this case where was getting no answers whatsoever before the bounty, or am I overthinking it and should award it to the first answer? Related questions in "Ask Question" page is better than the search tool Why only light nuclei are able to undergo nuclear fusion not heavy nuclei? Is it because of the binding energy or the binding energy per nuclei .  I am having trouble with this whole binding energy and nuclear fusion concept. I am a first year Ph. D student, and I have been working on a new topic of research.  I worked day and night to prove something new and verified it. I began my Ph. D while my supervisor was on travel, but he returned before I had been here for long.  When he returned, he told me we have to stop and not continue without any reasonable reasons.  After a few months he began treating me poorly---always belittling and underestimating---although I got two grants from a top conference, made videos and podcasts, and constantly received praise for my good work and personality.    It seems that I have been treated as a competitor, not a collaborator.  Although agreeing with my approaches in private, my supervisor said false words to the committee to take the decision and stop my Ph. D work!  It is not surprising, as there was another former senior Ph. D student who I met on campus, who was not allowed to defend his Ph. D: this same supervisor claimed he was not able to finish his dissertation although he had published in a peer reviewed journal and having citation as well, it was scary and not familiar.  In front of committee, he lied, and said something without proving. I asked if he can make a detailed constructive criticism, but he could not.  All I can say that they are a gang literally, and he said words that show that he is jealous and doesn't want to see me having self confidence in my self. I know no one will believe me, but this is the truth.  Honestly, I am distressed and I'm losing sleep.  I had this dream where there were many people who saw me fail.  All things considered, I don't know whether what happened is good or bad, and I definitely don't know what I should do next!  I would be grateful for your advice and whether there is someone has encountered any similar situation. Test if a website is alive from a C# application I am looking for the best way to test if a website is alive from a C# application. Background My application consists of a Winforms UI, a backend WCF service and a website to publish content to the UI and other consumers. To prevent the situation where the UI starts up and fails to work properly because of a missing WCF service or website being down I have added an app startup check to ensure that all everything is alive. The application is being written in C#, .NET 3.5, Visual Studio 2008 Current Solution Currently I am making a web request to a test page on the website that will inturn test the web site and then display a result. WebRequest request = WebRequest.Create(&quot;http://localhost/myContentSite/test.aspx&quot;); WebResponse response = request.GetResponse();  I am assuming that if there are no exceptions thown during this call then all is well and the UI can start. Question Is this the simplest, right way or is there some other sneaky call that I don't know about in C# or a better way to do it. Is it possible to restore a MySql database only using files from Data directory? $T(av_1 + bv_2) = aT(v_1) + bT(v_2)$  Why is this called linear? $f(x) =ax + b$, the simplest linear equation does not satisfy $f(x_1 + x_2) = f(x_1) + f(x_2)$.  Thank you. of Stack Overflow, all content posted on Stack Exchange sites by their users (i.e. you wonderful people) has been provided to the whole universe under . For my fellow non-lawyers, that license basically means:   Anyone can use any Stack Exchange posts at any time without having to ask for permission Making money off of the copied content is permitted You don't even have to copy stuff from here verbatim; you can just use it as a starting point and make whatever edits you want There are just two rules you have to follow:   You have to provide . Simple links to the original post and author info are just fine. You have to  and allow other people to use your content, as long as they follow these very same rules. How meta!    (If you ever forget any of that, and want to refresh your memory, the license info is linked to in the footer of every page.)  There are, in fact, a lot of people who republish varying amounts of our content for assorted reasons. Unfortunately, there are some Stack Content Republishers Attributing Poorly and/or Excelling at Ranking (SCRAPERs, for short).  In this context, "attributing poorly" means any use that doesn't follow our attribution rules or make any other reasonable attempt at give credit. This can get pretty egregious; I've seen SCRAPERs that not only don't link back to SE originals, but also use fake author info and post dates to make it harder to find originals. By "excelling at ranking," I'm referring to copycat sites that end up higher in Google results than the original SE sites do for the same content. That's not necessarily wrong, but in some cases, it indicates inappropriate SEO hackery.  So, the question is: what can you do if you spot a SCRAPER? Windows & Ubuntu dual boot.No menu to choose OS? I just installed Ubuntu alongside Windows 7. Now I cant boot Windows 7 because it automaticaly boots Ubuntu without displaying boot menu. How can I get menu with options to choose which Os to boot? Can anyone help? Why does the definition of limits of a function have strict inequality? Definition (As written in Michael Spivak's Calculus)     The function $f$ approaches a limit $l$ near $a$ means: for every $\epsilon &gt;0$ there is some $\delta &gt; 0$ such that, for all $x$, if $0&lt;|x-a|&lt;\delta$, then $|f(x)-l|&lt;\epsilon$.   my question is: why can't it be: $$0&lt;|x-a|\leq \delta,|f(x)-l|\leq \epsilon$$ After looking at limits of functions for a long time just to grasp it's meaning and using the definition quite a lot solving homework I realized I keep writing the same inequality without really understanding why.  The only explanation given in Spivak's book for this part of the definition goes over it without explaining the inequality. I tried looking for an explanation myself but wasn't really able to find anything wrong with it. Is it also possible to write the definition like that or is there a problem with that?   (first non-homework related question :p) I am building a blog type page, and I want to load items into the page as the user scrolls down, much like Google Reader, or Soup.io. How would you go about achieving this effect? I've seen some examples which read the height of the page, and have an onScroll even attached to the window so that as the user scrolls down we can test to see if they've scrolled down far enough to warrant loading more items. Soup.io's implementation seems to remove the old items as you scroll down so that the browser isn't dealing with an ever-increasingly large DOM tree. Which javascript libraries would be best suited to this task? Framing a combination of cells in the notebook Why are local variables not initialized in Java? says:  SSH_ASKPASS    If  ssh needs a passphrase, it will read the passphrase from the    current terminal if it was run from a terminal.  If ssh does not    have  a  terminal associated with it but DISPLAY and SSH_ASKPASS    are set, it will execute the program  specified  by  SSH_ASKPASS    and open an X11 window to read the passphrase.   I'd like SSH to use an askpass program even if it was run from a terminal.  On occasion, I have to connect to servers, where there's some delay in showing a password prompt (maybe due to network issues, maybe due to attempted reverse DNS lookups, …). I get annoyed and switch to something else, and forget about the attempted connection. (Insert joke about attention span of a goldfish.) When I finally get back to it, the prompt's timed out and even a correct password would just result in a closed connection.  Keys would be one solution, but not every system I use has my usual SSH keys. However, I usually use Ubuntu systems, and Ubuntu has an SSH askpass program installed by default.  If an askpass window popped up, however, I'd be immediately aware of it. That's a good enough compromise for me, if only I can get it to work. Lenovo Y510P: Battery wont charge past 60% On my y510p, I set Lenovos battery software to "Optimize battery health" while I was in Windows 8.1. I forgot to change it before overwriting that partition with Ubuntu, and now my battery in Ubuntu never charges past 59~60%. I think this is due to something in the BIOS because it persists despite my Windows partition being gone.   I've searched the BIOS but there's no mention of battery anywhere!  I'm using Ubuntu 14.04 LTS. How to draw line through group plots in pgfplots? This issue has been driving me crazy for the past 10-20h. I have a group plot (pgfplots) where I have 2 plots one under another. I'd like to draw a vertical line (e.g. a helpline at x=150e-6) that would go through all of them.  When drawing inside the axis or rather nextgroupplot environment I can use something like this: \draw[thin] (axis cs:150e-6,\pgfkeysvalueof{/pgfplots/ymin}) -- (axis cs:150e-6,\pgfkeysvalueof{/pgfplots/ymax}); but this allows me to draw only on one of the subplots. If I go outside the axis environment I am able to draw on the entire {tikzpicture}, but I can't use the axis reference.  \begin{figure*}[h] \centering \begin{tikzpicture}  \begin{groupplot}[       group style = {group size=1 by 2, x descriptions at=edge bottom, vertical sep=0.2cm},       ytick={0, 1.8},       ymin=0,       ymax=3,       xmin=0,       xmax=550e-6,       change x base=true,       x SI prefix=micro]  \nextgroupplot \addplot table [x index = {0}, y index = {1}, col sep=comma] {plots/plot1reduced.csv};  \nextgroupplot[x unit=s] \addplot table [x index = {0}, y index = {3}, col sep=comma] {plots/plot1reduced.csv};  \draw[thin] (axis cs:150e-6,\pgfkeysvalueof{/pgfplots/ymin}) -- (axis cs:150e-6,\pgfkeysvalueof{/pgfplots/ymax});  \end{groupplot} \end{tikzpicture} \caption{Case 1} \label{fig:case1plot} \end{figure*} Why has my database connection failed? Recently I have developed software using SQL Server 2012. Now when I try to connect, I get this error message:     Cannot connect to AAFI\SQLEXPRESSA network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 – Error Locating Server/Instance Specified) Enumerate within TikZ node Why not use a WAMP stack?