The direction of a correlation is either positive or negative. In a negative correlation, the variables move in inverse, or opposite, directions. In other words, as one variable increases, the other variable decreases. For example, there is a negative correlation between self-esteem and depression. In other words, the higher your self-esteem, the lower your feelings of depression.
Excel Communications was founded in 1988 by Dallas entrepreneur Kenny Troutt as a long distance reseller in the US telecom sector at the birth of telecom deregulation.
The first artificial heart was patented by Paul Winchell in 1963. Winchell subsequently assigned the patent to the University of Utah, where Robert Jarvik ultimately used it as the model for his Jarvik-7.eport Abuse. Artificial hearts date back to the mid-1950s when Dr. Paul Winchell first patented an artificial heart. William J. Kolff invented the first artificial heart and the first artificial kidney-dialysis machine.