Vortex beam as a positioning tool.

Remote positioning by precise measurements of lateral displacements of laser beams at large distances is inevitably disturbed by the influence of atmospheric turbulences. Here we propose the use of optical vortices, which exhibit lower transversal variations at an experimentally validated range of 100 meters. We show the higher precision of the localization of vortex points as compared with standard centroid-based assessment of Gaussian beams. Numerical simulations and experimental measurements show further improvements by averaging of the positions of up to four secondary vortices forming a stable constellation when higher values of the topological charges are used.

Role of the physiotherapist in the orthopaedic trauma department in the context of National Health Fund funding of medical procedures.

BACKGROUND: The present paper aims to demonstrate that physiotherapy in orthopaedic and trauma departments is part and parcel of a comprehensive treatment plan. MATERIAL AND METHODS: Hospital records of 66 patients treated in three orthopaedic trauma departments in 2011 were analysed. Basing on the requirements of the National Health Fund (Narodowy Fundusz Zdrowia--NFZ), reports were generated on the number of physiotherapy procedures provided. RESULTS: The mean age of the patients was 70.26 (SD=12.08) years. Sixty-two of them (93.94%) had undergone hip replacement and the remaining 4 (6.06%) had undergone knee replacement procedures. The patients spent a mean of 13 days in hospital (SD=3.66, range 9-30 days). The following physiotherapy procedures were applied: mobilisation in 48 subjects (72.73%), seating in 47 (71.21%), gait training in 48 (72.73%), exercises of the affected leg in 46 (69.70%), upper limb exercises in 38 (57.58%) and breathing exercises in 28 (42.42%). According to the NFZ regulations, the maximum number of patients per one physiotherapist in an orthopaedic department is 10, which requirement was met in only one of the three hospitals involved. CONCLUSIONS: 1. Arthroplasty procedures along with long bone fracture fixation are the most common causes of hospitalisation in orthopaedic trauma departments. 2. The departments involved in this study do not provide pre-operative rehabilitation. Physiotherapy begins at 3 days post surgery. 3. Most of the departments involved do not comply with the NFZ's requirement regarding the therapist-to-patient ratio.

Influence of a laser beam's frequency stability on dislocation of vortex points in an optical vortex interferometer.

New applications for optical vortex interferometers (OVIs) are under investigation. The precision of the OVI depends strongly on the accuracy of positioning of the vortex points, which requires more than one interferogram (fringe pattern), so the influence of the laser beam's frequency stability is important. We present an analysis of the influence of the laser beam's frequency stabilization on the accuracy of methods locating vortex points relative to dimensions in optical arrangements of OVIs.