In contrast to division of work, division of labour is the specialization of an individual workers' or organizations' skills, through education, training, and practice.
AR15 Trigger Upgrades. 1  The trigger is one of the most crucial elements in achieving the highest level of accuracy from any firearm. Installation of a quality trigger will permit a light pull with little or no creep and overtravel.
Aortic insufficiency (AI), also known as aortic regurgitation (AR), is the leaking of the aortic valve of the heart that causes blood to flow in the reverse direction during ventricular diastole, from the aorta into the left ventricle.