[Endemic struma and its relation to various drinking water factors in 4 communities of the Suhl district]. / Untersuchungen über die endemische Struma und ihre Beziehung zu verschiedenen Trinkwasserfaktoren in 4 Gemeinden des Bezirkes Suhl.

By means of anamnestic and clinical examinations carried out on 1,055 test persons of all age groups in four adjacent communities of the County of Suhl an average frequency of struma of 53.9% was stated. The strumata of the size stage I with a diffuse condition and a preference of the younger age groups and the female sex prevailed. The prophylactic and medicamentous measures of the combat against struma introduced up to 1984 are to be estimated as ineffective. The distinctly greater formation of struma (64.6%) which is to be proved in one community might be caused by a correlating significantly higher nitrate content of the drinking water with existing considerable deficiency of iodine. No connection could be found between the frequency of struma and the calcium and magnesium content of the drinking water as well as the hardness of water and the consumption of potassium permanganate. Within the framework of a complex combat against goitre an improvement of the iodised common salt prophylaxis, measures for the decrease of the nitrate content in drinking water and soil as well as a more effective registration and treatment of the strumata are necessary.

Linearitätsabweichungen bei Strahlungsmessungen mit Photovervielfachern.

Sources of nonlinear response of photomultiplier tubes are discussed, and examples are given for conditions where nonlinearities >10(-3) are possible. Slow fatigue nonlinearities were eliminated by a beat technique; the results therefore should be applicable to measurements of pulsed radiation at low or constant mean level. Nonlinearities caused by current takeover from a resistive voltage divider were compared with calculations. Reasons of inner nonlinearities were space charges: (a) between cathodexand first dynode (at cathode currents >10(-9) A, depending on cathode spot and wavelength) and (b) between the last dynodes. Up to approximately l-mA anode current proportionality was observed between currents and nonlinearities. Avoiding fatigue by pulsed operation, the range of linear response may be much expanded compared with dc operation.