Black Holes: Facts, Theory & Definition. Black holes are some of the strangest and most fascinating objects found in outer space. They are objects of extreme density, with such strong gravitational attraction that even light cannot escape from their grasp if it comes near enough.
Chemigation is the injection any chemical such as nitrogen, phosphorus or a pesticide into irrigation water and applied to the land using the irrigation system. The proper use of chemigation is recognized as a Best Management Practice (BMP) for irrigated agriculture.
This treatment is called intravesical therapy. There are two principal drugs that are used as intravesical chemotherapy or immunotherapy. 1  Bacille Calmette-Guerin or BCG is intravesical immunotherapy which causes an immune or allergic reaction that has been shown to kill cancer cells on the lining of the bladder.