I can't seem to find an answer to this. For a given configuration, say for a Hydrogen atom: the proton has properties which give it a positive charge. This is a known truth.  Now lets take Hydrogen's antiparticle (anti-Hydrogen) and compare the structure - All the information I've found so far only points to a difference in charge without explaining the structure that governs the charge of the proton or anti-proton.  I'm trying to understand what structural differences define a particle as being either matter or antimatter.  Can anyone help with this?
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.
Passing an array as a function parameter in JavaScript Best way to capture historical changes between levels in a dimensional hierarchy What is the cleanest way to capture changes between levels in a dimensional hierarchy?  I have the dimensional hierarchy [Area] > [Region] > [Location], where Area is the parent to Region and Region is the parent to Location. Location is lowest level of the hierarchy, and is associated with the fact table.  The business rules are: Locations are able to change the Region they are assigned to based on business need. Furthermore, Regions are able to change the Area they are assigned to.  We want to capture those changes so that when we do historical analysis, we can compare business metrics before and after a Location changed its Region, and a before and after a Region changed its Area.  What is the best way to do this?  The four ways that I have come up with all seem to have major drawbacks:   Using a bridge table between hierarchy levels requires that you use time bounds (effective start/end dates) to correctly identify which parent a child belongs to as you walk up the hierarchy. That makes queries prone to error, especially with hierarchies with many levels. Versioning a child record whenever its relationship to its parent changes (e.g., versioning Region A when it moves from Area A to Area B) and then cascading that change all the way down the hierarchy (e.g., creating new versions of Locations tied to Region A so that they are tied to the new Region A). Updating the child record's reference to the parent record, making you use time bounds to reassemble the correct history (prone to error). Always use time bounds when querying up the hierarchy to make sure Location A is associated with the correct Region (likewise, Region A is associated with the correct Area) for the moment of the fact being analyzed.   None of these seems clean to me.  Is there a better way?  Thanks a lot I've been trying to photograph lightning lately, as we have had some great storms in Colorado. I've had some difficulty getting a good vantage point, however, as almost all of these storms include rain as well. To keep my camera from getting drenched (I have weather-sealed lenses, but my camera body, a Canon 450D, is not weather sealed as far as I can tell), I've had to shoot under the eve of a building or under a thick canopy of trees, however that has greatly limited my ability to adapt to the changing weather and get get a vantage point on the best lightning.  Is there any equipment, something I can purchase or something home-made that has easy-to-find parts, that can help me protect my lens from the rain while still being able to shoot? Additionally, I've been getting rain on a UV filter I have on the front of my lenses, simply to prevent rain from getting on the front lens element itself. However, once a storm really gets going, so does the rain. Is there a simple solution to keep rain off the front of the lens? Anchor Text code string is automatically modified by WordPress I have created an ad for a merchant wanting to rent ad space on my website home page. After creating the ad, (anchor text and pic/graphics with embedded hyperlink) the merchant has requested I remove my url from the ad code. The anchor text along with the embedded hyperlinks links to the merchant's home page.  Problem is I don't know how my url was added to the code as I never inputted it in the original code in the first place. Somehow it was added by I think, WordPress or my server (PHP).  When I view the page source I do see my url was added to the ad code.  Can anyone help explain this and tell me how I can remove the url? Also, if I am able later to remove my url, how will it affect the hyperlink and anchor text?  Thank you, -Dan  Hi s_ha_dum,  I have read your answer and have now made sure the code reads as abosolute url.  Here it is with absolute url:  &lt;strong&gt;If you are interested in helping others treat and prevent hypertension, consider a healthcare degree from &lt;a href="http://elearning.loyno.edu/"&gt;Loyola Online Courses today!&lt;/a&gt;&lt;/strong&gt;   It still shows in page source however with my url addended to the code string.  What am I not understanding? Thank you! CSV text files loading error / crash in QGIS 2.18.8 I got a problem when I try to load tab-separated text files in the "Create a layer from the delimited text file" tab (that one with de comma symbol). After normally selecting the X and Y fields and clicking OK, the reference coordinate system (SRC) selector screen appears, then the program closes by itself. I had uploaded more than a hundred of this type of file by the same procedure in the previous version of QGIS (2.14 Essen) and have no problem, but since I updated to version 2.18.8 (Las Palmas) I can not load any files or .CSV type.   Do anyone knows what's happening? Am I doing anything wrong? If the plural of ‘man’ is ‘men,’ shouldn’t the plural of ‘German’ be ‘Germen’? What makes these two words so different that 'man' is changed to 'men', but 'German' is changed to 'Germans'? Why is the Yang–Mills existence and mass gap problem so fundamental? Ref:   Can anyone please explain why the Yang–Mills Existence and Mass Gap problem is so important / fundamental to contemporary mathematics (and, presumably, theoretical / mathematical physics)?  If possible, please include the following in your answer / response:  (1) Why the problem is so fundamental / important - for both mathematics and theoretical / mathematical physics; (2) How the solution to the problem would impact research in the above two fields; (3) (If applicable) What progress has been made so far in resolving it; (references to papers, books, other resources would be helpful).  I'm an upper-level undergraduate in theoretical physics, and so am seeking an answer / response at such level. Embedding DLLs in a compiled executable Is it possible to embed a pre-existing DLL into a compiled C# executable (so that you only have one file to distribute)? If it is possible, how would one go about doing it?  Normally, I'm cool with just leaving the DLLs outside and having the setup program handle everything, but there have been a couple of people at work who have asked me this and I honestly don't know. I have a rather long footnote which breaks a listing in two parts, unnecessarily.  Since the listing is more important then the footnote I'd rather lake to have the footnote split.   Can I customize (one or all) footnotes to have a maximal length before they are continued on the next page? Or can I manually split a footnote in two to get the effect? What is the best way to level up in Clash of Clans Does anybody know of a method to trigger an event in Prototype, as you can with jQuery's trigger function?  I have bound an event listener using the observe method, but I would also like to be able to fire the event programatically.  Thanks in advance Why would turning off a sink faucet stop the shower? I am going to change my machine: from a laptop with Ubuntu to another laptop where I am going to install Ubuntu...  I am quite happy with the current system, what I am afraid of is having to rebuild everything from 0.  So what do people often do to clone an Ubuntu system? That may include the data, packages, shortcut settings, etc... I have read several introductory texts about LSTM online, but none of them give a rigorously mathematical explanation of what the model actually does. For instance, why does the forget gate forget any more than any of the other gates in the LSTM unit?  Which papers and/or books should I read if I want to get a deeper understanding of LSTM? Why must a planet be in a star's "habitable zone" to have life? Fighter War Magic, Using Booming Blade / GFB If my Fighter (Eldritch Knight) use War Magic (PHB p. 75) to use the cantrip Booming Blade, will I be able to use my Extra Attack, and bonus action attack, to make 3 attacks at level 7? Multiple logistic regression power analysis I'm new to Ubuntu. I tried installing it with Windows 8.1, but failed I lost all my files.  I have successfully formatted my PC and installed Ubuntu, but how do I install codecs to play audio and videos files ? Stack Exchange doesn't allow me to answer protected questions because I gave away earned rep in bounties I noticed that I can't answer protected questions. I don't want to actually, but it says:        It was , but I also didn't have an ability to answer other protected questions.  I earned 270 reputation points + 100 reputation point bonus. Then I  350 reputation points as a bounty. Then I earned 59 reputation points. Today I started another bounty (50 reputation points), etc – I offered 4 bounties with total 500 rep.  Despite the fact I started from the association bonus, I must have an ability to answer protected questions, as I earned reputation points here. But offered them as bounties.    I now have enough reputation points, but I would like it to be fixed, because I like offering bounties very much.  I would like system to check for my bounties when it checks if I can answer protected question. What is the best way to add a user to the sudoer group?