How do I use multi-touch gestures on a MacBook Air?
Apple Magic Trackpad multitouch configuration
Im creating a community user from an Apex code. When our internal users (non-admins) run the code they are getting following error. (This was working fine when we test the feature in sandbox)     SObjectException: Field is not writeable: User.ProfileId   The code is       //Grab Community User Profile     Profile p = [Select Id, Name from Profile where Name = :COMMUNITY_PROFILE LIMIT 1];       User PortalUser = new User();          PortalUser.UserName = Con.Email+'-POC';         PortalUser.ContactId = Con.Id;         PortalUser.ProfileId = p.id;         PortalUser.Email = Con.Email;         PortalUser.EmailEncodingKey = 'UTF-8';         PortalUser.FirstName = Con.FirstName;         PortalUser.LastName = Con.LastName;         PortalUser.TimeZoneSidKey = 'America/Los_Angeles';         PortalUser.LocaleSidKey = 'en_US';         PortalUser.LanguageLocaleKey = 'en_US';          if (Con.LastName.length() &gt;= 8){             PortalUser.Alias = Con.LastName.substring(0, 7);             }else{             PortalUser.Alias = Con.LastName;         }             SObjToInsert.add(PortalUser); Matrices that can only be permutation matrices How to prove that if $A$ and $B$ are two $n×n$ matrices with non negative integer entries such that $AB=I$ then $A$ and $B$ are permutation matrices?  Permutation matrices are matrices with the columns just a permutation of the identity matrix. How do I proceed. Can somebody give hint? Citations with no bibliography at the end How do you produce a document with citations (\citep, \citet) working properly in the paper but without a bibliography at the end?  I've come up with one solution that is bad because it breaks my makefile.  latex file.tex bibtex file # comment out \bibliography{} command latex file.tex   Similarly, is there a way to produce the bibliography with no accompanying text?  Again, I've come up with a solution: fill an otherwise blank .tex file with \nocite{} commands.  However, this is a pain because I have to keep two files synced by hand (and regular expressions to search for \citep{author1, author2} can be a huge pain when there are pagebreaks...). In all the discussions about how the heavy elements in the universe are forged in the guts of stars and especially during a star's death, I usually hear that once the star begins fusing lighter atoms to produce iron (Fe) that's the end of the star's life and the whole system collapses onto itself; and based on how massive the star was initially, it has different outcome - like a white dwarf, a neutron star or a black hole. I have rarely heard a detailed explanation of how the elements heavier than iron are produced. I would appreciate a convincing explanation of this process. Intuitive/direct proof that a rectangle partitioned into rectangles each with at least one integer side must itself have an integer side A challenge problem asked to show that if rectangle $R$ with axis-parallel sides is partitioned into finitely many subrectangles $R_1,R_2,\ldots,R_n$ (also with axis-parallel sides), such that each $R_i$ has at least one integer side length, then $R$ must also have at least one integer side length. The only proof I've seen, although simple, is quite unintuitive. Namely you look at the integral  $$ \int_R e^{2 \pi i (x+y)} dx dy $$ and note that the integral is $0$ if and only if $R$ has an integer side length, and then note that by assumption the integral is $0$ over all the $R_i$, hence summing the integral over all $R_i$ gives that the integral is also $0$ over $R$. Can someone give a more direct/intuitive argument that doesn't use voodoo like a complex-valued integral? I have recently noticed a huge (>3.5GB) file in the DCIM/.thumbnails folder. I have tried deleting it, but the next time I open the Camera app it rebuilds the file (and locks up the phone, sometimes displaying a "media scanning in progress" message, in the process.)  The total file size of all the (approximately 2,000) photos displayed in the Gallery is around 500MB. There are in addition around 35,000 images in folders which contain .nomedia files to instruct Android to ignore the media therein. The total file size of these is around 1.5GB. The Gallery app is correctly ignoring these images, but I wonder whether the Camera app is misbehaving and actually processing them.  I think this problem has emerged since the ICS upgrade ... either when the phone (Samsung Galaxy Note) was first updated from Gingerbread or at some later date.  Any ideas, please? Someone's car hit our metal bar gate, so one of the rods is bent as shown in the photo. What kind of a tool can I use to bend this back, so it's straight? Thank you! A site URL changed and now its icon in SEDE is broken Is the usage of text embedded in an image a bad practice, for very controlled uses? What are your thoughts on writing your text in images?  I'm not saying throughout the whole website... But in certain key locations like image carousels. And I'm not talking about the special cases where you have font types that browsers can't render. I'm talking about text that uses standard fonts and is not too big (3/4 bullets).  Should I embed the text in the images that compose the carousel? Or should I apply the text to the images as "real text" HTML?  What are the advantages/ disadvantages of using text in an image? Can't install MySQL on Mountain Lion The context for my question might be a bit strange.   I have stuttering and therefore I have some difficulties pronouncing some words starting with particular phonetics. And I've found that if a sentence starts with a /th/ sound, it makes me feel uncomfortable.  Especially in the word is "thanks" or "thank you".  So I want to know if there's a popular alternative for "thank you" that may not seem strange and that unnatural. I've searched the website and I know there are alternatives like "I appreciate your help." but that sounds a bit overly formal for me. (Or is it? correct me if I'm mistaken.) How to search something on across multiple sites with a single Google query? I tried   (search term site:stackoverflow.com) OR (search term site:superuser.com) OR (search term site:stackexchange.com) search term site:stackoverflow.com,superuser.com,stackexchange.com search term site:stackoverflow.com site:superuser.com site:stackexchange.com   None of them works. What is the correct way to search? Graphing the amount of time a function takes 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. How to prove that the center of the dihedral group $D_{2n}$ is $\{1,r^{n}\}$ and the center of $D_{2n-1}$ is $\{1\}$?  I don't know how to prove it in this general case. When solving this issue (  ), I did a function so that the plugin would auto-hide from all users except one (me:).  The flaw is that it only auto-hides when active.  At first, it was a mu-plugin, but I had to enable/disable it manually. It really doesn't need to run all the time, as it may slow the site (?) or even contain some sensitive manipulation of the site's language (another question mark).  But mainly the motivation is that I don't want the client activating/deactivating/deleting this plugin (is for my own use), and don't want it cluttering her own plugins list.  So, decided to split the functions in two plugins:   One is a Must-Use used to hide the regular one.  The other will be activated/deactivated upon necessity and is the one from the above linked issue.   But now I run into another question: how to hide one plugin from the Must-Use listing? Since when did kidnapping come to include adults too? As per , the word 'kidnap' originated to denote nabbing away of a child. When and how did kidnap come to denote nabbing of adults?  Update: Just found a link to a  that mentions kidnapping of souls. Now not sure how correct the above link is. I am looking to create realistic car movement using vectors permission reporting on sudoers I'm looking for a good, consistent and easy way to do a report of sudoers permissions for every user and group on the system. For users, I want the report to include permissions granted via group membership. Animation Blending Basics Say I have a framework with characters that can run and walk and of course, stand still.  Am I right in thinking that animation blending is the process of smoothly transitioning between these by generating dynamic animations at runtime?  If so, what is the basic theory of how this works, and how would I implement it?