Avascular necrosis (AVN) of the hip is an abnormal and possibly crippling condition in which blood cannot get to the hip bone. When the blood supply to the bone is blocked, the area without blood supply can die. This may lead to collapse of the bone requiring replacement with an artificial hip joint.
Nitrogen Fixing Trees for Permaculture Flowers of the leguminous tree, Kowhai, the national flower of New Zealand Nitrogen fixation is a pattern of nutrient cycling which has successfully been used in perennial agriculture for millennia. This article focuses on legumes, which are nitrogen fixers [â¦]
Although nitrogen is abundant in the atmosphere, a few species of microbes are the only organisms that can use it in this form. All other organisms depend on these bacteria. Certain bacteria produce enzymes that convert or fix gaseous nitrogen (N 2) into a form other organisms can use, such as ammonium (NH 4 +) or nitrate (NO 3-). Often nitrogen-fixing bacteria come to depend on plants for food, forming a symbiotic (or mutually beneficial) relationship.