To obtain such positron microbeam, it is necessary to use objective lenses, which are commonly used in the electron microscopy. We also attempted to form the positron microbeam using a positron beam for the positron diffraction experiment and a SEM optics [6]; [7] ; [8].
Publicly Traded Companies that Benefited from Forced or Slave Labor, 1929-1945 CalPERS
Even in regions where African slavery predominated, such as the sugar plantations in Portuguese Brazil and in the West Indies, Indian labor continued to be used. And in many Spanish colonies, where the plantations did not flourish, Indians provided the bulk of unfree labor through the colonial era. In other words, the growth of African slavery in the New World did not diminish the use of unfree Indian labor, particularly outside of the plantation system.