It is possible that what appear to be references to one ship are in fact coincidental descriptions of different destroyers sharing a single name. For instance, several ships of different classes have used the name Vengeance, and not all of them were Imperator-class destroyers. There has also been more than one Iron Fist. In these cases, successive commanders have kept the name when they moved to newer vessels upon promotion.
Why Twin Studies? Twins provide a valuable source of information for health and psychological research, as their unique relationship allows researchers to pull apart and examine genetic and environmental influences. Twin study findings have been influential in detecting and treating various diseases and psychological disorders. How are they able to do this? Twin studies allow researchers to examine the overall role of genes in the development of a trait or disorder.
THE genetic makeup of a child is a stronger influence on personality than child rearing, according to the first study to examine identical twins reared in different families. The findings shatter a widespread belief among experts and laymen alike in the primacy of family influence and are sure to engender fierce debate.'If in fact twins reared apart are that similar, this study is extremely important for understanding how personality is shaped,'' commented Jerome Kagan, a developmental psychologist at Harvard University. ''It implies that some aspects of personality are under a great degree of genetic control.''.