117 research outputs found

    Underground Muography with Portable Gaseous Detectors

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    Muography is a novel imaging technology based on particle physics instrumentation to reveal density structure of hill-sized objects. The cosmic muon flux is attenuated while penetrating into the ground, thus the differential local flux correlates with the overburden density-length. Underground muography exploits the close-to-zenith flux, while main challenges became portability, low power consumption, and robustness against the out-of-the-laboratory environment. Various fields could benefit from this non-invasive imaging, eg. speleology, mining, archeology, or industry. Portable gaseous tracking detector systems have been designed, built, and successfully used in several underground locations. This paper presents the designed portable muography systems, the main requirements, and measurement campaigns for calibration, natural caves, and cultural heritage

    C2 prosthesis: anterior upper cervical fixation device to reconstruct the second cervical vertebra

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    Destruction of the second cervical vertebra leads to a highly unstable situation. Reconstruction is difficult because the axis plays a central role in rotatory movements and has a unique function in redistributing axial loads. The axis transfers the axial load of the two lateral masses of the atlas to three surfaces on the third cervical vertebra: the two articular facets and the vertebral body. As reconstruction is difficult and the instability in this region is life threatening, pathological processes are often treated less radically compared to other areas of the cervical spine. However, this more moderate approach may result in worse outcomes and prognoses. This paper presents the development of a new implant (C2 prosthesis) and two illustrative cases describing the implementation of this new implant. The C2 prosthesis provides anterior support and therefore allows a more radical surgical approach

    Cavity Location by Muon Tomography

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    Muon tomography (or muography) is one of the most effective methods for locating unknown underground voids. If the geometric conditions are favorable for the measurements, no other geophysical method can compete with it, neither when resolution nor when simplicity is considered. In the last years, thanks to the continuous R&D of our low-cost, portable muon detectors, as well as the improved data processing methods, we have completed several successful natural and artificial cavity exploration projects, demonstrating that location is possible even if the characteristic size of cavity is 5% of the rock thickness between the detector and surface. Here we present case studies carried out in Hungarian underground sites, where we could find unknown cavities and verify the method by locating known artificial shafts and adits with high precision. Reaching these unknown caves is in progress either by conventional caving exploration techniques or by drilling. Further measurements are ongoing by the new upgraded detectors. By decreasing gas consumption and supporting electric power by solar cells, we are able to measure even at remote locations without the need of any direct access, for durations of several months

    Multi-Wire Detectors for Underground Muography

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    The use of cosmic muons in imaging large artificial or geological structures started to flourish in the last decades, with the technological advancement in particle physics instrumentations. Muography became a most effective way to locate hidden density anomalies in geological structures, which includes revealing unknown parts of natural cave systems underneath the mountains. Our group has developed a series of gaseous multi-wire particle detectors for muography applications, with targets ranging from volcanology to speleology. Advancements in durability, power consumption, portability, and acquisition system have been proven via field measurements in natural sites besides extensive laboratory testing. The poster is dedicated to give details on the main requirements, components, and solutions which are means to transform standard particle detectors to be practically applicable in underground muography. We will present the expanded scale of experimental systems, targeting upgraded high-resolution tomography, hole-fit small-scale devices, and even economical simplified versions for exploratory measurements. These muography detectors could soon become effective novel tools in geo-sciences

    Analysis of pairwise comparison matrices: an empirical research

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    Pairwise comparison (PC) matrices are used in multi-attribute decision problems (MADM) in order to express the preferences of the decision maker. Our research focused on testing various characteristics of PC matrices. In a controlled experiment with university students (N = 227) we have obtained 454 PC matrices. The cases have been divided into 18 subgroups according to the key factors to be analyzed. Our team conducted experiments with matrices of different size given from different types of MADM problems. Additionally, the matrix elements have been obtained by different questioning procedures differing in the order of the questions. Results are organized to answer five research questions. Three of them are directly connected to the inconsistency of a PC matrix. Various types of inconsistency indices have been applied. We have found that the type of the problem and the size of the matrix had impact on the inconsistency of the PC matrix. However, we have not found any impact of the questioning order. Incomplete PC matrices played an important role in our research. The decision makers behavioral consistency was as well analyzed in case of incomplete matrices using indicators measuring the deviation from the final order of alternatives and from the final score vector

    Complex X chromosome rearrangement associated with multiorgan autoimmunity

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    BACKGROUND: Turner syndrome, a congenital condition that affects 1/2,500 births, results from absence or structural alteration of the second sex chromosome. Turner syndrome is usually associated with short stature, gonadal dysgenesis and variable dysmorphic features. The classical 45,X karyotype accounts approximately for half of all patients, the remainder exhibit mosaicism or structural abnormalities of the X chromosome. However, complex intra-X chromosomal rearrangements involving more than three breakpoints are extremely rare. RESULTS: We present a unique case of a novel complex X chromosome rearrangement in a young female patient presenting successively a wide range of autoimmune diseases including insulin dependent diabetes mellitus, Hashimoto's thyroiditis, celiac disease, anaemia perniciosa, possible inner ear disease and severe hair loss. For the genetic evaluation, conventional cytogenetic analysis and FISH with different X specific probes were initially performed. The complexity of these results and the variety of autoimmune problems of the patient prompted us to identify the exact composition and breakpoints of the rearranged X as well as methylation status of the X chromosomes. The high resolution array-CGH (assembly GRCh37/hg19) detected single copy for the whole chromosome X short arm. Two different sized segments of Xq arm were present in three copies: one large size of 80,3 Mb from Xq11.1 to Xq27.3 region and another smaller (11,1 Mb) from Xq27.3 to Xq28 region. An 1,6 Mb Xq27.3 region of the long arm was present in two copies. Southern blot analysis identified a skewed X inactivation with approximately 70:30 % ratios of methylated/unmethylated fragments. The G-band and FISH patterns of the rearranged X suggested the aspect of a restructured i(Xq) chromosome which was shattered and fortuitously repaired. The X-STR genotype analysis of the family detected that the patient inherited intact maternal X chromosome and a rearranged paternal X chromosome. The multiple Xq breakages and fusions as well as inverted duplication would have been expected to cause a severe Turner phenotype. However, the patient lacks many of the classic somatic features of Turner syndrome, instead she presented multiorgan autoimmune diseases. CONCLUSIONS: The clinical data of the presented patient suggest that fragmentation of the i(Xq) chromosome elevates the risk of autoimmune diseases
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