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Mid-cervical kyphosis in diastrophic dysplasia (DD) with cord compression and weakness has been recognized for the last three decades. A strikingly similar situation exists in Larsen's syndrome (LS), an otherwise unrelated problem of weakness with lay joints and dislocations with typical facies. Forty patients with DD were studied of whom seven had cervical spine kyphosis: one patient had spontaneous correction over the ensuing two decades. Seven patients with LS were studied of whom four had cervical spine changes with cord compression. There was one sudden death among the patients with LS and no cases of spontaneous correction. Muscle weakness in DD and LS should lead to evaluation of cervical spine kyphosis with cord compression. Plain films, CT and recently MRI are useful. [ABSTRACT FROM AUTHOR]

An innovative way for wind energy to participate in some sort of frequency control using kinetic energy stored in the rotor for a fast power reserve that could be delivered in a short period (from several seconds up to a few tens of seconds) is presented. This kinetic-energy-based fast reserve is ensured despite wind speed variations – a disoptimisation of the power coefficient through the modification of the rotor speed set point or through the pitch control. In case of a frequency drop, the power coefficient could then be increased to produce more energy. This approach could help to reduce the dynamics and the depth of the frequency drops and therefore allow wind farms to participate in frequency control. Basic economic aspects of the provision of fast power reserve by wind turbines as a function of the amount of reserve considered are also discussed. [ABSTRACT FROM AUTHOR]

Test of Pulse Width Modulated (PWM) controllers using real-time digital simulators is a particular challenge regarding their computational capabilities. These simulators use a fixed time-step, and thus, switching events detection is hazardous and the sampling of PWM signals cannot be performed with the required accuracy. To overcome the problem, a new solution is proposed in this paper: the sampling of the inputs signals is improved with a hardware interface and averaged models are used to avoid switching events in the simulation. To validate the method, a benchmark was realized to test a PWM controller for Distribution STATic COMpensator (DSTATCOM). [ABSTRACT FROM AUTHOR]

Control of the brushless doubly fed machine (BDFM) based on traditional multiple reference frames is complex. To simplify the control scheme, a new and simpler derivation of the dq model of the BDFM is proposed, leading to a unified-reference-frame model. This way, a simple dq model can be established, which could be an interesting tool for control-synthesis tasks. In order to determine the unified reference dq model, restrictions related to BDFM operation, as well as the exact rotor-cage configuration, have been considered. The proposed model has been validated by several experimental results. The work could facilitate future research on improved BDFM field-oriented control strategies. [ABSTRACT FROM AUTHOR]

Fracture non-union in the pediatric population may span the age range from childhood to adolescence. Fracture non-union in children and adolescents is often due to an underlying cause such as affliction with neurofibromatosis or osteogenesis imperfecta. Although less commonly seen, non-union may occur in the otherwise healthy pediatric population. We report three cases of fracture non-union of the distal end of the fibula in the pediatric age group. All three were characterized by persistent local pain and tenderness following injury with radiographic evidence of fracture non-union. All three had undergone conservative treatment with extended periods of immobilization. Following surgery, all three had marked improvement of their local symptomatology. One patient's course was complicated by reflex sympathetic dystrophy syndrome. In two patients, resection of the un-united fragment at the distal fibula resulted in marked relief from pain without any increase in ankle instability. We postulate that the fracture non-union resulted in a fibrotic reaction that was so extensive that ankle stability was maintained even after removal of the fracture fragment. [ABSTRACT FROM AUTHOR]

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