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Objective: Globally, obstetric fistula is a tragic outcome following obstructed labour. Failure of complex repair and post‐operative incontinence are common. We describe an innovative surgical technique incorporating the rectus abdominus flap at the time of fistula repair. Design: Retrospective case series. Setting: Malawi, Fistula Care Centre. Methods: Patients were followed for 3 months after discharge to determine continence and healing. Results: Five of six patients were continent at 3 months and one was lost to follow‐up by dry at a one month post‐operative phone call. There were no major complications. Conclusions: The rectus abdominus flap may be a useful adjunct to repair of complex obstetric fistula. [ABSTRACT FROM AUTHOR]

An adaptive self-tuning gauge control system has been implemented on a cold-rolling aluminum mill, using an 80286-based microcomputer system. The mill process is modeled as a second-order system with one input (unwind tension reference) and one output (gauge error). The model parameters are estimated on line using a recursive least squares estimation algorithm. The inputs to the estimator are correlated in time so that the estimator is not affected by the gauge measurement transport delay. Based on the estimated model parameters and a pole-placement design, a control signal is calculated. The regulator structure is a filtered version of a discrete PID controller. Digital filters are used on the inputs to the controller and estimator and as part of an energy-detection scheme used to ensure that estimation only takes place when the system is excited in the appropriate frequency range. Implementation details and results are described.

One of the distinguishing characteristics of a supercell thunderstorm is the presence of a rotating updraft. During the past 30 years, various hypotheses have been proposed to explain the initiation and maintenance of rotation. However, attempts to verify the initiation process have been frustrated by the lack of multiple-Doppler radar measurements at the time that the first rotating updraft appears. Discussed in this paper are dual-Doppler radar measurements that successfully captured the initiation and evolution of rotation in the Agawam, Oklahoma, storm of 6 June 1979, which occurred during the storm-scale phase of the Severe Environmental Storms and Mesoscale Experiment (SESAME). The process leading to updraft rotation appears to follow that proposed in 1968 by Fujita and Grandoso, whereby a middle-altitude vorticity couplet formed on the downwind flanks of a strong nonrotating updraft, with cyclonic vertical vorticity on the right-forward flank and anticyclonic vertical vorticity on the left-forward flank. With low-altitude flow approaching the storm from the right, a new updraft developed on the rightward-propagating gust front located along the right edge of the storm beneath the cyclonic vorticity region. The growing updraft acquired cyclonic rotation at middle altitudes by entraining and stretching the ambient vertical vorticity. Subsequent right-flank updrafts in the Agawam storm appear to have developed middle-altitude rotation in the same manner. Based on observations made within the Agawam storm and its immediate environment, the conventional hypothesis that employs low-altitude vertical shear of the horizontal wind as the vorticity source did not likely play a significant role in establishing updraft rotation.

The North Dakota Thunderstorm Project was conducted in the Bismarck, North Dakota, area from 12 June through 22 July 1989. The project deployed Doppler radars, cloud physics aircraft, and supporting instrumentation to study a variety of aspects of convective clouds. These included transport and dispersion; entrainment; cloud-ice initiation and evolution; storm structure, dynamics, and kinematics; atmospheric chemistry; and electrification. Of primary interest were tracer experiments that identified and tracked specific regions within evolving clouds as a means of investigating the transport, dispersion, and activation of ice-nucleating agents as well as studying basic transport and entrainment processes. Tracers included sulfur hexafluoride ([SF.sub.6]), carbon monoxide, ozone, radar chaff, and silver iodide. Doppler radars were used to perform studies of all scales of convection, from first-echo cases to a mesoscale convective system. An especially interesting dual-Doppler study of two splitting thunderstorms has resulted. The objectives of the various project experiments and the specific facilities employed are described. Project highlights and some preliminary results are also presented.