In recent years, the Brazilian government has encouraged affirmative action programs for persons considered to be "African-descendant" and also for Amerindians. This is happening, in part, through the created systems of preferred admissions (quotas) for racial minorities. Other measures include priority in land reform for areas populated by remnants of "quilombos". The government notes that these groups have historically been discriminated against because of slavery and the Portuguese conquest of the indigenous peoples. They became landless and are represented among the poorest segments of Brazilian society, while the European or White population dominates the upper classes. Such efforts in affirmative action have been criticized because of the ambiguity of racial classification in Brazil. Some people have tried to use this system for personal advantage.