" The best models are fully encapsulated, meaning that they implement every aspect of that real world object of interest to the domain of interest, and that they don't have any extra code that doesn't model the real world. Encapsulation also means that the class is implemented in such a way that the internal representation of data is not exposed to the user of the object . The impedance mismatch between these two worlds, that of events, and that of objects, is something that's been recognized for a long time. Getting these two worlds to cooperate requires a lot of 'glue code' to make them work together. The 'model-view-controller' paradigm introduces the controller object in between the view (the GUI class) and the model (the object) to communicate between the other two objects. The actual implementation of the controller object can vary quite a bit, but the idea of an object to 'transform' events to changes in data and execution of methods is the essence of this pattern. What does "event driven" mean? Was there ever an application which did not respond to user events. Center Home Model. ? Just because an application responds to events does not mean it is "event driven". "

" Amongst the proton, neutron, and electron, those fermions which constitute the vast majority of matter, the Standard Model considers only the electron a fundamental particle. The proton and neutron are aggregates of smaller particles known as quarks, which are held together by the strong interaction. The fundamental fermions in the Standard Model are given in the table. Table Left handed fermions in the Standard Model Fermion (Left-handed) Symbol Electric charge Weak charge* Weak isospin Hypercharge Color charge* Mass** Generation 1 Electron e -1 2 -1/2 -1/2 1 0. 511 MeV Electron neutrino νe 0 2 +1/2 -1/2 1 < 50 eV Positron ec 1 1 0 1 1 0. 511 MeV Electron antineutrino 0 1 0 0 1 < 50 eV Up quark u +2/3 2 +1/2 +1/6 3 ~5 MeV *** Down quark d -1/3 2 -1/2 +1/6 3 ~10 MeV *** Anti-up antiquark uc -2/3 1 0 -2/3 ~5 MeV *** Anti-down antiquark dc +1/3 1 0 +1/3 ~10 MeV *** Generation 2 Muon μ -1 2 -1/2 -1/2 1 105. 6 MeV Muon neutrino νμ 0 2 +1/2 -1/2 1 < 0. Home Model Park Used5 MeV Anti-Muon μc 1 1 0 1 1 105. 6 MeV Muon antineutrino 0 1 0 0 1 < 0. "