Force tracking system using a semi-active valve lag damper for vibration reduction in helicopters

This paper considers a closed-loop force tracking system for an active valve lag damper intended for vibration reduction applications in helicopters. The mathematical model of the damper is treated in a simplified form and is the basis for controller design. Due to the inherent nonlinearity of the damper, a controller is constructed using concepts from nonlinear control, namely, nonlinear dynamic inversion (NDI). Tuning methods according to several frequency-domain requirements are introduced and a realistic simulation example demonstrates the effectiveness of the controller

The Role of Psychiatrists in Consultation-Liaison Psychiatry

Infections with Pseudomonas aeruginosa increase morbidity in primary ciliary dyskinesia (PCD) and cystic fibrosis (CF) patients. Both diseases are associated with a defect of the mucociliary clearance; in PCD caused by non-functional cilia, in CF by changed mucus. Whole genome sequencing of P. aeruginosa isolates from CF patients has shown that persistence of clonal lineages in the airways is facilitated by genetic adaptation. It is unknown whether this also applies to P. aeruginosa airway infections in PCD. We compared within-host evolution of P. aeruginosa in PCD and CF patients. P. aeruginosa isolates from 12 PCD patients were whole genome sequenced and phenotypically characterised. Ten out of 12 PCD patients were infected with persisting clone types. We identified convergent evolution in eight genes, which are also important for persistent infections in CF airways: genes related to antibiotic resistance, quorum sensing, motility, type III secretion and mucoidity. We document phenotypic and genotypic parallelism in the evolution of P. aeruginosa across infected patients with different genetic disorders. The parallel changes and convergent adaptation and evolution may be caused by similar selective forces such as the intensive antibiotic treatment and the inflammatory response, which drive the evolutionary processes