103 research outputs found

    The Micromegas Project for the ATLAS Upgrade

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    Micromegas is one of the detector technologies (along with the small Thin Gap Chambers) that has been chosen for precision tracking and triggering purposes of the ATLAS muon forward detectors in the view of LHC luminosity increase. To fulfill the requirements of such upgrade, several prototype micromegas detectors were tested in recent test beam campaigns with high energy hadron beams at CERN. Performance studies and results on spatial resolution for perpendicular and inclined tracks, efficiency, as well detector performance and comparison to simulation in a magnetic field are presented. Moreover, an overview of detector performance after neutron, X-ray, gammas and alphas exposure and construction achievements of large area micromegas detectors are presented

    Euroscepticism trends in the european elections of 2014 and 2019

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    Διπλωματική εργασία--Πανεπιστήμιο Μακεδονίας, Θεσσαλονίκη, 2021.A thesis presented on the aspects of Euroscepticism, beginning with its first conceptualization, and covering the various social groups it represents. First of all, we will introduce Euroscepticism as a notion and we will become aware of its history and the different types that it can be categorized according to theoreticians. As soon as we do this, we will follow its path through the last decades and we will indulge in different expressions of Euroscepticism, searching also for the roots of this phenomenon. Our main focus is the last two European elections, so we will mostly refer to the last decade and the augmentation of Euroscepticism until 2019. Each state of the European Union (EU) shall be examined separately as the rise of Euroscepticism is not the same everywhere and Euroscepticism can be expressed in different variants, depending on the motivation and the aim of a Eurosceptic vote. Brexit is also a timely topic which should be inducted in the study as a separate chapter, since it is an ongoing phenomenon which has already affected EU and would for sure show whether the United Kingdom will entice more member-states to withdraw from the Union and help in the prevalent growth of Euroscepticism in the near future. Furthermore, we ought to investigate which kind of Euroscepticism can have a positive effect in the concept of European Integration as the EU can become stronger through this challenge and prove that its contribution is significant and therefore, there are fundamental reasons which support its existence in the European scene. In a final stage, we will analyze the answers of a questionnaire prepared particularly for this dissertation in regards with how 100 European citizens, who participated in the survey, see their state’s membership in the EU and the rise of Euroscepticism the last decade

    Reconstruction of primary vertices at the ATLAS experiment in Run 1 proton–proton collisions at the LHC

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    This paper presents the method and performance of primary vertex reconstruction in proton–proton collision data recorded by the ATLAS experiment during Run 1 of the LHC. The studies presented focus on data taken during 2012 at a centre-of-mass energy of √s=8 TeV. The performance has been measured as a function of the number of interactions per bunch crossing over a wide range, from one to seventy. The measurement of the position and size of the luminous region and its use as a constraint to improve the primary vertex resolution are discussed. A longitudinal vertex position resolution of about 30μm is achieved for events with high multiplicity of reconstructed tracks. The transverse position resolution is better than 20μm and is dominated by the precision on the size of the luminous region. An analytical model is proposed to describe the primary vertex reconstruction efficiency as a function of the number of interactions per bunch crossing and of the longitudinal size of the luminous region. Agreement between the data and the predictions of this model is better than 3% up to seventy interactions per bunch crossing

    Short-term effects of manual therapy plus capacitive and resistive electric transfer therapy in individuals with chronic non-specific low back pain : a randomized clinical trial study

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    Background and Objectives: Chronic non-specific low back pain (CNSLBP) is defined as back pain that lasts longer than 12 weeks. Capacitive and resistive electric transfer (TECAR) therapy utilizes radiant energy to generate endogenous heat and is widely used for the treatment of chronic musculoskeletal pain. The aim of this study was to investigate the efficacy of manual therapy (MT) program combined with TECAR therapy in individuals with CNSLBP. Materials and Methods: Sixty adults with CNSLBP were randomly divided equally into three groups. The first group followed an MT protocol in the lumbar region (MT group), the second group followed the same MT protocol combined with TECAR therapy (MT + TECAR group) using a conventional capacitive electrode as well as a special resistive electrode bracelet, and the third group (control group) received no treatment. Both intervention programs included six treatments over two weeks. Pain in the last 24 h with the Numeric Pain Rating Scale (NPRS), functional ability with the Roland–Morris Disability Questionnaire (RMDQ), pressure pain threshold (PPT) in the lumbar region with pressure algometry, and mobility of the lumbo-pelvic region through fingertip-to-floor distance (FFD) test were evaluated before and after the intervention period with a one-month follow-up. Analysis of variance with repeated measures was applied. Results: In the NPRS score, both intervention groups showed statistically significant differences compared to the control group both during the second week and the one-month follow-up (p 0.05). Conclusions: The application of an MT protocol with TECAR therapy appeared more effective than conventional MT as well as compared to the control group in reducing pain and disability and improving PPT in individuals with CNSLBP. No further improvement was noted in the mobility of the lumbo-pelvic region by adding TECAR to the MT intervention

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    KID Project:an internet-based digital video atlas of capsule endoscopy for research purposes

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    BACKGROUND AND AIMS: Capsule endoscopy (CE) has revolutionized small-bowel (SB) investigation. Computational methods can enhance diagnostic yield (DY); however, incorporating machine learning algorithms (MLAs) into CE reading is difficult as large amounts of image annotations are required for training. Current databases lack graphic annotations of pathologies and cannot be used. A novel database, KID, aims to provide a reference for research and development of medical decision support systems (MDSS) for CE. METHODS: Open-source software was used for the KID database. Clinicians contribute anonymized, annotated CE images and videos. Graphic annotations are supported by an open-access annotation tool (Ratsnake). We detail an experiment based on the KID database, examining differences in SB lesion measurement between human readers and a MLA. The Jaccard Index (JI) was used to evaluate similarity between annotations by the MLA and human readers. RESULTS: The MLA performed best in measuring lymphangiectasias with a JI of 81\u200a\ub1\u200a6\u200a%. The other lesion types were: angioectasias (JI 64\u200a\ub1\u200a11\u200a%), aphthae (JI 64\u200a\ub1\u200a8\u200a%), chylous cysts (JI 70\u200a\ub1\u200a14\u200a%), polypoid lesions (JI 75\u200a\ub1\u200a21\u200a%), and ulcers (JI 56\u200a\ub1\u200a9\u200a%). CONCLUSION: MLA can perform as well as human readers in the measurement of SB angioectasias in white light (WL). Automated lesion measurement is therefore feasible. KID is currently the only open-source CE database developed specifically to aid development of MDSS. Our experiment demonstrates this potential

    Measurement of jet fragmentation in Pb+Pb and pppp collisions at sNN=2.76\sqrt{{s_\mathrm{NN}}} = 2.76 TeV with the ATLAS detector at the LHC

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    Measurement of the W boson polarisation in ttˉt\bar{t} events from pp collisions at s\sqrt{s} = 8 TeV in the lepton + jets channel with ATLAS

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    Measurement of the bbb\overline{b} dijet cross section in pp collisions at s=7\sqrt{s} = 7 TeV with the ATLAS detector

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