Most researchers believe that Olde Robert Selfe was the ancestor of most of the Self family in America. Arriving in Virginia in the 1600s, Robert Selfe appears to have been descended from Walter Selfe of Cripplegate, London, England. The name Self is thought to be a shortened version of Seawolf, dating back to the early Viking voyages along the English coast.
A stress reaction is the lowest grade of the three levels of bone injury. A stress reaction is essentially the early stages of a stress fracture. This occurs when the stresses affecting the bone occur at a faster rate than the rate at which the bone is able to rebuild itself.
A shear stress, denoted Ï (Greek: tau), is defined as the component of stress coplanar with a material cross section. Shear stress arises from the force vector component parallel to the cross section. Normal stress, on the other hand, arises from the force vector component perpendicular to the material cross section on which it acts.