Steel and elastomer assembly that has a central through-passage equal to or greater in diameter than the riser bore and that may be positioned in the riser string to reduce local bending stresses.
The Mazatec people are an indigenous people who inhabit an area known as the Sierra Mazateca in the state of Oaxaca in southern Mexico, as well as some communities in the adjacent states of Puebla and Veracruz.
Normally, the Classic period in Mesoamerica is characterized as the stage in which the arts, science, urbanism, architecture, and social organization reached their peak. This period was also dominated by the influence of Teotihuacan throughout the region, and the competition between the different Mesoamerican states led to continuous warfare.