151 research outputs found
Unpredictability of hip behavior in Dyggve-Melchior-Clausen syndrome: A mid-term assessment of siblings
SummaryDyggve-Melchior-Clausen syndrome is a rare spondylo-epiphyseal disease, which almost constantly leads to both bilateral hip degeneration and dislocation. Few authors have reported to date the surgical management of this orthopaedic disorder. We present two new cases affecting siblings. One brother was treated by unilateral triple pelvic osteotomy combined with varus osteotomy of the proximal femur; the other was treated by bilateral Pemberton osteotomies with varus osteotomy of the proximal femur. At a respective 5-year and 3-year follow-up delay, both cases had evolved towards progressive subluxation recurrence along with severe hip degeneration. Based on both our experience and literature review, it seems that one should avoid operating these hips unless pain renders surgery mandatory. Total hip arthroplasty seems the only reliable surgical solution at the adult age and paediatric surgeons should keep in mind that previous femoral osteotomies will make it more challenging for adult orthopaedic surgeons to implant on a remodeled anatomy
Observations of the Sun using LOFAR Baldy station
We report first results of solar spectroscopic observations carried out with the Baldy LOFAR (LOw-Frequency ARray) station, Poland from October 2016 to July 2017. During this time, we observed different types of radio emission: type I and type III radio bursts. Our observations show that the station is fully operational and it is capable to work efficiently in the single station mode for solar observations. Furthermore, in this paper we will briefly describe the observational technique and instrument capabilities and show some examples of first observations. (C) 2018 COSPAR. Published by Elsevier Ltd. All rights reserved.Peer reviewe
Interferometric imaging of the type IIIb and U radio bursts observed with LOFAR on 22 August 2017
Context. The Sun is the source of different types of radio bursts that are associated with solar flares, for example. Among the most frequently observed phenomena are type III solar bursts. Their radio images at low frequencies (below 100 MHz) are relatively poorly studied due to the limitations of legacy radio telescopes.Aims. We study the general characteristics of types IIIb and U with stria structure solar radio bursts in the frequency range of 20-80 MHz, in particular the source size and evolution in different altitudes, as well as the velocity and energy of electron beams responsible for their generation.Methods. In this work types IIIb and U with stria structure radio bursts are analyzed using data from the LOFAR telescope including dynamic spectra and imaging observations, as well as data taken in the X-ray range (GOES and RHESSI satellites) and in the extreme ultraviolet (SDO satellite).Results. In this study we determined the source size limited by the actual shape of the contour at particular frequencies of type IIIb and U solar bursts in a relatively wide frequency band from 20 to 80 MHz. Two of the bursts seem to appear at roughly the same place in the studied active region and their source sizes are similar. It is different in the case of another burst, which seems to be related to another part of the magnetic field structure in this active region. The velocities of the electron beams responsible for the generation of the three bursts studied here were also found to be different.Peer reviewe
- …