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The SC-cut anharmonic mode 301 and 310 resonators have been presented over past several years at the EPTF. Compared to main mode lateral field excited resonators, the anharmonic mode resonators exhibit a lower motional resistance and few times higher motional capacitance. For this reason, it is inherently easier to make frequency calibration and control of an anharmonic mode based oscillator. At Tele and Radio Research Institute the lateral field excited resonators employing the main mode 300 and the anharmonic modes 301 and 311 were designed and manufactured. The same swept quartz material was used for all resonators, and the manufacture was based on the same technological process. The resonators were mounted in oscillators. Then the short term instability, the long term drift and the thermal frequency offset were measured, using the conventional methods of measurement. Measurements of the long term frequency drift were carried out in the laboratory with constant ambient temperature 20 floc. Moreover the long term frequency drift was corrected for the atmospheric pressure and air humidity. As a result of the measurements, the short term instability of 7 + 1 0~1 O~~/ l s range and the long term drift of in S+ZOxlO' " /day, after 1 month were achieved. The electronic components utilized in oscillator parameters influence on oscillator parameters was observed. After changing the components that exhibited highest instability the short and long term instability measurements were repeated. The measured long term drift was in the range of 1+ 6xlO-"/day. The parameters of anharmonic mode lateral field excited resonators are presented. The short term and long term instability and thermal frequency offset of oscillators utilizing lateral field anharmonic mode resonators are compared with those of oscillators utilizing classical lateral field excited SC cut resonators.

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A long-term review of 82 patients (117 hips) who had Colonna's operation for congenital dislocation of the hip has been carried out. Although early assessments had shown a high proportion of good results these deteriorated with time. At our latest review of 61 hips, with an average follow-up of 30 years, 34% had moderate, and 66% severe, osteoarthrosis; many of these patients now need a total hip replacement. We conclude that Colonna's operation is only indicated in a small number of cases. It should never be carried out over the age of 6 years, and only in younger children when there is severe underdevelopment of the acetabulum or where procedures which preserve the articular cartilage are unlikely to be successful.