In the United States, the carriers have effectively exited the tower business. Most sold their towers to companies like American Tower (AMT) and Crown Castle. These companies construct, maintain and operate the towers, and lease space to the carriers. Tower operators such as AMT actively seek to lease the same tower to multiple carriers, and this is a key metric of their financial success. A best-in-class tower operator will have 2-3 carrier tenants per tower.
The descending aorta is the part of the aorta beginning at the aortic arch that runs down through the chest and abdomen. The descending aorta anatomically consists of two portions or segments, the thoracic and the abdominal aorta, in correspondence with the two great cavities of the trunk in which it is situated.
Noun. 1. aorta-the large trunk artery that carries blood from the left ventricle of the heart to branch arteries. arteria, arterial blood vessel, artery-a blood vessel that carries blood from the heart to the body.ascending aorta-the ascending part of the aorta as it emerges from the left ventricle.aortic arch-the part of the aorta that arches and turns downward. descending aorta-the descending part of the aorta that branches into the thoracic and abdominal aortae. abdominal aorta-a branch of the descending aorta.scending aorta-the ascending part of the aorta as it emerges from the left ventricle. aortic arch-the part of the aorta that arches and turns downward. descending aorta-the descending part of the aorta that branches into the thoracic and abdominal aortae. abdominal aorta-a branch of the descending aorta.