72 research outputs found
The Filtering of the Posturographic Signals Shows the Age Related Features
Objective. Lower frequencies of slow oscillations of the posturographic signals can be removed using high-pass filtering. This procedure releases postural reflexes possessing higher frequencies and lower amplitude range. Mutual dependence between the x and y components of posturographic signals was analyzed using principal component analysis (PCA). The posturographic signals of old patients with idiopathic gait disturbance were compared with the control group of similar age and with younger patients. There was also the analysis of the influence of the eyes state (open versus closed) and the head position (normal or bent back). The statistically significant differences in the mutual dependence between x and y components between the groups of patients were analyzed using MANOVA. The significant differences were observed mainly in the range of filter frequencies f=0.1–1.5 Hz and f=2.2–5.5 Hz with a maximum effect at approximately 4-5 Hz. A detailed post-hoc analysis is also presented. The differences in the higher frequency range suggest the main disturbance to be connected with the spinal reflexes. Visual and vestibular support appear insufficient for postural stability control in the idiopathic gait disturbance group. The results suggest that idiopathic gait disturbance is the final stage of the aging process of postural system
The St. Anne’s Mountain Geopark : "The King Wanderer" is back on his throne!
Due to numerous geological phenomena on a virtually small territory, the St. Anne's Mountain and its areas has an excellent chance to become one of the most significant geotouristic regions in Poland. The designed geopark, apart from its main goal which is to promote the earth education, will also affect the tourism and economy growth within the region. The area will enable us to look into the future of our planet through the prism of processes, which created its environment in the past. Discovering the earth mysteries, acquainting oneself with the contents of drafted plates, and close contact to geology will encourage people, especially the younger generation, to explore the adjacent surroundings and the whole world. The St. Anne's Mountain was given national status by the Ministry of the Environment on the basis of the review, made by the Polish Geological Institute - National Research Institute Upper Silesian Branch in Sosnowiec, entitled: The St. Anne's Mountain Geopark - the documentation and suggestions on its protection. Research along with observation results on the field and laboratory works between 2008 and 2010 were included in the above mentioned review
EPID-a useful interfraction QC tool
Biomedical accelerators used in radiotherapy are equipped with detector arrays which are commonly used to obtain the image of patient position during the treatment session. These devices use both kilovolt and megavolt x-ray beams. The advantage of EPID (Electronic Portal Imaging Device) megavolt panels is the correlation of the measured signal with the calibrated dose. The EPID gives a possibility to verify delivered dose. The aim of the study is to answer the question whether EPID can be useful as a tool for interfraction QC (quality control) of dose and geometry repeatability. The EPID system has been calibrated according to the manufacturer's recommendations to obtain a signal and dose values correlation. Initially, the uncertainty of the EPID matrix measurement was estimated. According to that, the detecting sensitivity of two parameters was checked: discrepancies between the planned and measured dose and field geometry variance. Moreover, the linearity of measured signal-dose function was evaluated. In the second part of the work, an analysis of several dose distributions was performed. In this study, the analysis of clinical cases was limited to stereotactic dynamic radiotherapy. Fluence maps were obtained as a result of the dose distribution measurements with the EPID during treatment sessions. The compatibility of fluence maps was analyzed using the gamma index. The fluence map acquired during the first fraction was the reference one. The obtained results show that EPID system can be used for interfraction control of dose and geometry repeatability
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