K-electron capture to positron emission ratios in allowed transitions

All available experimental K/ beta + and epsilon / beta + ratios for allowed transitions are reviewed. A critical comparison is made between experimental and theoretical K/ beta + ratios. The following questions are asked: (i) can these experiments be used to derive the magnitude of a possible induced tensor interaction? (ii) is there a departure from theory, particularly in the high Z region? It is pointed out that more experimental work is necessary, especially for values of Z>30.