Upregulation of glial cell line-derived neurotrophic factor (GDNF) in the rat cochlea following noise. Pharmacologic manipulation of the labyrinth with novel and traditional agents delivered to the inner ear.
Slavery in the United States was the legal institution of human chattel slavery that existed in the United States of America in the 18th and 19th centuries after it gained independence and before the end of the American Civil War.he United States was polarized over the issue of slavery, represented by the slave and free states divided by the MasonâDixon line, which separated free Pennsylvania from slave Maryland and Delaware.
Foundations of Slavery in America. In the early 17th century, European settlers in North America turned to African slaves as a cheaper, more plentiful labor source than indentured servants (who were mostly poorer Europeans). After 1619, when a Dutch ship brought 20 Africans ashore at the British colony of Jamestown, Virginia, slavery spread throughout the American colonies.