" Therefore, it would be possible to "overtake" a neutrino, choosing a reference frame in which its direction of motion is reversed without affecting its spin (making it right-handed). Since then, physicists have revised the Standard Model to allow neutrinos to have mass, which make up additional free parameters beyond the initial 19 . A further extension of the Standard Model can be found in the theory of supersymmetry, which proposes a massive supersymmetric "partner" for every particle in the conventional Standard Model. Supersymmetric particles have been suggested as a candidate for explaining dark matter. Although supersymmetric particles have not been observed experimentally to date, the theory is one of the most popular avenues of research in theoretical particle physics. References Textbooks Griffiths, David J. (1987) Introduction to Elementary Particles, Wiley, John & Sons, Inc. Car Magazine Model ISBN 0471603864 Journal Articles Y. Hayato et al. "

" View instability vs. model stability If constructed correctly, models can enjoy a fair degree of stability (owing to the stability of the domain model), whereas user interface code usually undergoes frequent and sometimes dramatic change (typically because of usability problems, the need to support growing classes of users, or simply the need to keep the application looking "fresh"). Separating the view from the model makes the model more robust, because the developer is less likely to "break" the model while reworking the view. Attempting to stitch these two worlds together in a hand coded method without architecture is very common, and results in the model object being polluted with knowledge of the interface, and vice-versa. This makes the code very inflexible and difficult to maintain. For this reason (among others), many programming shops develop the user interface design early in the process of design, and freeze the interface early. The unfortunate side effect of this is that the domain of the problem often isn't clearly understood by the programmers until late in the implementation process. 2 2 Car Fast Furious Model Thus, just at the time that the developers are finally competent to create a good interface, they are kept from changing it. MVC models allow the code to be more flexible later in the development process, allowing for changes that make sense at the time it makes sense to make them. "