It will be interesting to look back in twenty or thirty years to see how U.S. society has changed. Countries with falling populations like Germany believed that they could bring in immigrants to join the workforce and that they would pay into the social system to support the large numbers of retiring Germans but it doesn’t seem like it’s working out the way they planned. First generation immigrant students do much worse than native German kids in school and second generation immigrant children fare even worse so I don’t know how beneficial they will be to the German economy. The massive immigrant community in France is also not doing well as we saw on TV last year.
http://service.spiegel.de/cache/international/0,1518,416429,00.html
" 'Germany is the country with the largest disparity' between first and second generation immigrants, the report says. 'Second-generation students lag behind their native peers by 93 score points, which is equivalent to one and a half proficiency levels. This is particularly disconcerting, as these students have spent their entire school career in Germany.' "
http://www.maynardije.org/columns/bowman/051109_workforce/ (U.S. workforce)
Below is an example of a mixing problem for liquids that describes the amount of salt, represented by y(t), in the solution as a function of time, t. If things like the crime rate or academic proficiency level (e.g., SAT) of new immigrants is known, I wonder if a similar technique to the mixing problem could be used to predict the crime rate or level of academic proficiency for the society t years in the future.
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