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With a detailed chemistry scheme for the middle atmosphere up to 70 km which has been added to the 3-D Karlsruhe simulation model of the middle atmosphere (KASIMA), the effects of coupling chemistry and dynamics through ozone are studied for the middle atmosphere. An uncoupled version using an ozone climatology for determining heating rates and a coupled version using on-line ozone are compared in a 10-month integration with meteorological analyses for the winter 1992/93 as the lower boundary condition. Both versions simulate the meteorological situation satisfactorily, but exhibit a too cold lower stratosphere. The on-line ozone differs from the climatological data between 20 and 40 km by exhibiting too high ozone values, whereas in the lower mesosphere the ozone values are too low. The coupled model version is stable and differs only above 40 km significantly from the uncoupled version. Direct heating effects are identified to cause most of the differences. The well-known negative correlation between temperature and ozone is reproduced in the model. As a result, the coupled version slightly approaches the climatological ozone field. Further feedback effects are studied by using the on-line ozone field as a basis for an artificial climatology. For non-disturbed ozone conditions realistic monthly and zonally averaged ozone data are sufficient to determine the heating rates for modelling the middle atmosphere.

Summary Knowledge of the pathophysiology and natural course of perforated peptic ulcer is incomplete. Recurrences are due to the use of misconceived and incorrect surgical techniques. Recurrences after partial selective vagotomy in 8 patients validates the high claims made for the technique. The local situation and the specific requirements of PSV (dissection of the esophagus) impede the procedure in emergencies. Only 3 of 52 patients had signs of ulcer prior to perforation. Suture of the perforation was performed with only 3 recurrences detected in the follow-up studies. Therefore PSV and partial gastrectomy are reserved for special cases.