With bottom-up to the top and beyond

In this thesis, the measurement of the inclusive and differential production cross-sections of a top quark in association with an anti-top quark at large transverse momenta in proton-proton collisions, as well as one of the first direct interpretations of such a measurement in the framework of effective field theories (EFT) are presented. The measurement is based on data collected with the ATLAS detector at the Large Hadron Collider at CERN and corresponds to an integrated luminosity of 139 fb-1. Events of the process tt → WbWb→lvbqqb in the region of large transverse momenta are analyzed. After unfolding the data to particle level, the cross-section is presented as function of several kinematic variables relevant to this process. In order to validate the predictions based on the Standard Model of particle physics, the data is compared to several predictions and effects of higher order contributions in quantum chromodynamics are investigated. In this measurement, the impact of systematic uncertainties on the energy reconstruction of jets is reduced by employing a novel method. It introduces a scaling of the energies of the jets in order to decrease discrepancies in the reconstruction of jet energies in data and the different predictions. Using this precision measurement, an indirect and model-independent search for physics beyond the Standard Model (BSM) in the framework of EFT is performed. In particular, the effects of two EFT operators on the coupling of the top quark to gluons and other quarks are investigated. A model based on the two operators OtG and O(8)tq in the top-quark sector of the EFT framework is employed to interpret the measurement in the context of BSM physics. Bayesian statistics is used in order to set limits on the effects of these operators via their respective Wilson coefficients CtG and C(8)tq. This analysis is among the very first direct EFT interpretations of a differential cross-section measurement in the top-quark sector. The determined limits on C(8)tq are competitive with recent global combinations, while soundly treating all parameters of the interpretation and without employing any of the assumptions, typical in global combinations. Both Wilson coefficients are found to be compatible with the SM.In dieser Arbeit wird die Messung der inklusiven und differentiellen Produktionswirkungsquerschnitte eines Top-Quarks in Verbindung mit einem Anti-Top-Quark bei großen Transversalimpulsen in Proton-Proton-Kollisionen vorgestellt. Des Weiteren wird eine der ersten direkten Interpretationen einer solchen Messung im Rahmen der effektiven Feldtheorien (EFT) vorgestellt. Die Messung basiert auf Daten, die mit dem ATLAS-Detektor am Large Hadron Collider am CERN aufgenommen wurden und einer integrierten Luminosität von 139 fb-1 entsprechen. Es werden Ereignisse des Prozesses tt → WbWb→lvbqqb im Bereich großer Transversalimpulse analysiert. Nach der Entfaltung der Daten auf Teilchenebene wird der Wirkungsquerschnitt als Funktion mehrerer, für diesen Prozess relevanter, kinematischer Variablen untersucht. Um die Vorhersagen auf der Grundlage des Standardmodells der Teilchenphysik zu überprüfen, werden die Messungen mit verschiedenen Vorhersagen verglichen und die Auswirkungen von Korrekturen höherer Ordnung in der Quantenchromodynamik untersucht. Bei dieser Messung werden die Auswirkungen systematischer Unsicherheiten auf die Energierekonstruktion von Jets durch den Einsatz einer neuartigen Methode verringert. Dazu wird eine Skalierung der Energien der Jets eingeführt, um die Diskrepanzen bei der Rekonstruktion der Jet-Energien in den Daten und den verschiedenen Vorhersagen zu verringern. Mit dieser Präzisionsmessung wird eine indirekte und modellunabhängige Suche nach Physik jenseits des Standardmodells (BSM) im Rahmen der EFT durchgeführt. Insbesondere werden die Auswirkungen von zwei EFT-Operatoren auf die Kopplung des Top-Quarks an Gluonen und andere Quarks untersucht. Ein Modell, das auf den beiden Operatoren OtG und O(8)tq im Top-Quark-Sektor der EFT basiert, wird zur Interpretation der Messung im Kontext von Suchen nach BSM-Physik konstruiert und verwendet. Mit Hilfe der Bayes'schen Statistik werden die Auswirkungen dieser Operatoren über ihre jeweiligen Wilson-Koeffizienten CtG und C(8)tq begrenzt. Diese Analyse ist eine der ersten direkten EFT-Interpretationen einer differentiellen Wirkungsquerschnittsmessung im Top-Quark-Sektor. Die ermittelten erlaubten Parameterbereiche für C(8)tq sind konkurrenzfähig mit den jüngsten globalen Kombinationen, wobei alle Parameter der Interpretation konsistent behandelt werden und keine der für globale Kombinationen typischen Annahmen getroffen werden. Beide Wilson-Koeffizienten erweisen sich als kompatibel mit dem SM

Die visuelle Repräsentation des Klimawandels in Dokumentarfilmen. Eine multimodale kritische Diskursanalyse

Die vorliegende Arbeit analysiert zwei englischsprachige Dokumentarfilme über den Klimawandel mit entgegengesetzten Standpunkten – den amerikanischen Kinodokumentarfilm „An Inconvenient Truth“ (2006), welcher die anerkannte Konsensposition hinsichtlich der These einer gegenwärtigen von den Menschen verursachten globalen Erwärmung vertritt, und den als Antwort auf diesen angepriesenen britischen Fernsehdokumentarfilm „The Great Global Warming Swindle“ (2007), dessen Argumentation sich der Diskursposition des sogenannten Klimawandel-Skeptizismus zuordnen lässt. Die Analyse fragt danach, welche Unterschiede sich in den visuellen und verbalen Repräsentationen des Klimawandels sowie in den Argumentationen der beiden Filme feststellen lassen. Den theoretischen Hintergrund für ein Konzept der Repräsentation bilden zwei semiotische Theorien: Mit dem triadischen Zeichenkonzept von Peirce wird der Klimawandel als ein abstraktes Phänomen konzeptualisiert, welches sich in natürlichen Anzeichen in der Welt zeigt. Mit dem soziosemiotischen Ansatz von Kress und van Leeuwen wiederum werden die kommunikativen Funktionen von visuellen Repräsentationen in Diskursen über Klimawandel untersucht. Der methodologische Ansatz der Analyse greift auf Analyseinstrumentarien der Wiener Kritischen Diskursanalyse und der soziosemiotischen Diskursanalyse zurück und verbindet diese mit argumentationstheoretischen Grundlagen sowie neueren Theorien der visuellen Argumentation. In der Analyse werden zunächst unterschiedliche Kontextebenen der beiden Dokumentarfilme betrachtet, die Makrostruktur der Filme herausgearbeitet und jeweils ein kurzer Abschnitt detailliert analysiert. Die abschließende vergleichende Analyse deckt unterschiedliche Strategien auf, wie der Klimawandel in den beiden Dokumentarfilmen repräsentiert wird. Es lässt sich feststellen, dass der konsensorientierte Film auf visuellem Beweismaterial des Klimawandels fokussiert, während der skeptische Film Bilder hauptsächlich symbolisch gebraucht, um die Konsensposition als alarmistisch zu entlarven und den Klimawandel als natürlich und positiv darzustellen.This thesis analyses two documentary films about climate change with opposing standpoints: The American documentary “An Inconvenient Truth” (2006) argues for the widely accepted consensus regarding a human-induced global warming. The British TV-documentary “The Great Global Warming Swindle” (2007) was billed as a response to this film. It advances a standpoint that is referred to as “climate change scepticism”. The analysis explores the differences in the visual and verbal representation of climate change as well as in the argumentation of the films. Two theories of semiotics serve as the theoretical background for the concept of representation: The triadic concept of signs by Peirce is used to conceptualise climate change as an abstract natural phenomenon, which materialises as visible symptoms. The social semiotic approach by Kress and van Leeuwen is used to explore the communicative functions of visual representations in discourses about climate change. The methodological approach for the analysis is a Critical Discourse Analysis that combines social semiotics, the Discourse-Historical Approach, argumentation theory and new theories of visual argumentation. The analysis examines different levels of context of the two films, provides an outline of their macrostructures and analyses two short sections of the films in detail. The comparative analysis reveals different strategies of representing climate change in the two films. It concludes that “An Inconvenient Truth” focuses on images as visual evidence of climate change, while “The Great Global Warming Swindle” uses images symbolically to expose the consensus as alarmist and to depict climate change as natural and beneficial

Englisch und Deutsch in „internationalen“ Studiengängen: Kompetenz, Verwendung und Einschätzungbei Studierenden und Lehrenden

The present paper reports on an empirical study conducted in 2008-09 investigating the role of German and English in International Study Programmes. Our main interests are the language usage and the linguistic experiences of students and lecturers / professors in such multilingual study settings and the constellation of multilingualism in the university and in the students’ environment. Additionally, the study investigates the types of language support offered and their implementation, as well as the ways in which students perceive and use them. The first section outlines the design and methodological approach of the study. This is followed by a summary of the students’ language test results in English and German. The second section presents some of the major findings of our study, drawing on data from the student and teacher questionnaires and interviews. The final section provides a brief discussion of some pedagogical, linguistic and language policy implications of the present study

Critical media literacy against the backdrop of the digital transformation. Media and information literacy (MIL) and critical media literacy (CML) in comparison

Kompetentes und kritisches Medienhandeln ist eine gesellschaftliche Herausforderung, die auch die (politische) Erwachsenenbildung vor zentrale Aufgaben stellt. Im Beitrag werden zwei Konzepte der Medienkompetenz diskutiert, welche die politische Dimension des Medienhandelns betonen und dabei nützliche Ansatzpunkte für die Erwachsenenbildung bieten: das Media and Information Literacy (MIL) Konzept der UNESCO und das Konzept der Critical Media Literacy (CML) nach Douglas Kellner und Jeff Share. Beiden Konzepten liegt die Annahme zugrunde, dass Medienkompetenz nicht auf eine rein technische, funktionale Perspektive reduziert werden kann, sondern dass es einer ganzheitlichen, intersektionalen und interdisziplinären Ausrichtung bedarf, um den vielfachen gesellschaftlichen Herausforderungen in Zeiten der Digitalisierung gerecht zu werden. Vor allem gelte es, so ein Fazit der AutorInnen, ErwachsenenbildnerInnen selbst mit kritischer Medienkompetenz auszustatten und das Thema als Querschnittsmaterie in den Angeboten der Erwachsenenbildung zu etablieren. Da ErwachsenenbildnerInnen als MultiplikatorInnen fungieren, können sie dazu beitragen, Bewertungs-, Reflexions- und Handlungskompetenzen im Zeitalter der Digitalisierung und Mediatisierung gesamtgesellschaftlich zu fördern. (DIPF/Orig.)Competent and critical media practice is a societal challenge that is also facing adult (political) education. The article discusses two media literacy concepts that stress the political dimension of media use as social action and offer useful starting points for adult education: the UNESCO media and information literacy (MIL) concept and the critical media literacy (CML) concept developed by Douglas Kellner and Jeff Share. Both concepts rest upon the common assumption that media literacy cannot be reduced to a purely technical, functional perspective but that a holistic, intersectional and interdisciplinary orientation is required to meet multiple societal challenges in times of digital transformation. One of the authors conclusions is that it is necessary to provide adult educators with critical media literacy and to establish it as an interdisciplinary topic in adult education offerings. Since adult educators function as multipliers, they can contribute to the promotion of assessment, reflection and action competencies in all of society in the age of digital transformation and mediatization. (DIPF/Orig.

Quantification and reduction of cross-vendor variation in multicenter DWI MR imaging: results of the Cancer Core Europe imaging task force

Magnetic resonance imaging; Radiomics; Measurement VariabilityImatges per ressonància magnètica; Radiòmica; Variabilitat de mesuraImágenes por resonancia magnética; Radiómica; Variabilidad de medidaObjectives In the Cancer Core Europe Consortium (CCE), standardized biomarkers are required for therapy monitoring oncologic multicenter clinical trials. Multiparametric functional MRI and particularly diffusion-weighted MRI offer evident advantages for noninvasive characterization of tumor viability compared to CT and RECIST. A quantification of the inter- and intraindividual variation occurring in this setting using different hardware is missing. In this study, the MRI protocol including DWI was standardized and the residual variability of measurement parameters quantified. Methods Phantom and volunteer measurements (single-shot T2w and DW-EPI) were performed at the seven CCE sites using the MR hardware produced by three different vendors. Repeated measurements were performed at the sites and across the sites including a traveling volunteer, comparing qualitative and quantitative ROI-based results including an explorative radiomics analysis. Results For DWI/ADC phantom measurements using a central post-processing algorithm, the maximum deviation could be decreased to 2%. However, there is no significant difference compared to a decentralized ADC value calculation at the respective MRI devices. In volunteers, the measurement variation in 2 repeated scans did not exceed 11% for ADC and is below 20% for single-shot T2w in systematic liver ROIs. The measurement variation between sites amounted to 20% for ADC and < 25% for single-shot T2w. Explorative radiomics classification experiments yield better results for ADC than for single-shot T2w. Conclusion Harmonization of MR acquisition and post-processing parameters results in acceptable standard deviations for MR/DW imaging. MRI could be the tool in oncologic multicenter trials to overcome the limitations of RECIST-based response evaluation.Open Access funding enabled and organized by Projekt DEAL. This study has received funding by Cancer Core Europe for the travel expenses of M. Bach traveling with the MR – Phantom between centers

Muscarinic M1 receptors modulate endotoxemia-induced loss of synaptic plasticity

Septic encephalopathy is associated with rapid deterioration of cortical functions. Using magnetic resonance imaging (MRI) we detected functional abnormalities in the hippocampal formation of patients with septic delirium. Hippocampal dysfunction was further investigated in an animal model for sepsis using lipopolysaccharide (LPS) injections to induce endotoxemia in rats, followed by electrophysiological recordings in brain slices. Endotoxemia induced a deficit in long term potentiation which was completely reversed by apamin, a blocker of small conductance calcium-activated potassium (SK) channels, and partly restored by treatment with physostigmine (eserine), an acetylcholinesterase inhibitor, or TBPB, a selective M1 muscarinic acetylcholine receptor agonist. These results suggest a novel role for SK channels in the etiology of endotoxemia and explain why boosting cholinergic function restores deficits in synaptic plasticity. Drugs which enhance cholinergic or M1 activity in the brain may prove beneficial in treatment of septic delirium in the intensive care unit

Numerical study of augmented lagrangian algorithms for constrained global optimization

To cite this article: Ana Maria A.C. Rocha & Edite M.G.P. Fernandes (2011): Numerical study of augmented Lagrangian algorithms for constrained global optimization, Optimization, 60:10-11, 1359-1378This article presents a numerical study of two augmented Lagrangian algorithms to solve continuous constrained global optimization problems. The algorithms approximately solve a sequence of bound constrained subproblems whose objective function penalizes equality and inequality constraints violation and depends on the Lagrange multiplier vectors and a penalty parameter. Each subproblem is solved by a population-based method that uses an electromagnetism-like (EM) mechanism to move points towards optimality. Three local search procedures are tested to enhance the EM algorithm. Benchmark problems are solved in a performance evaluation of the proposed augmented Lagrangian methodologies. A comparison with other techniques presented in the literature is also reported

Correlation between pre-therapeutic TPS and VEGF concentrations, in the serum of patients with cancer of the uterine cervix, and early effects of therapy

AimTo assess the relationship between pre-therapeutic serum TPS and VEGF levels and the results of treatment as measured immediately after completion of therapy.Materials/MethodsThe study included 146 women treated for cancer of the uterine cervix. Of these, 37 women were in stage I, 43 in stage II, 59 in stage III and 7 in stage IV of disease progression according to the FIGO classification. The ages of the patients ranged from 31 to 80 years. The dominant cancer observed was squamous cell carcinoma which accounted for more than 97% of cases. Samples were taken before commencement of treatment. Patients were treated by a combination of methods including radiochemotherapy, radical radiotherapy and palliative radiotherapy. The effects of therapy were graded after completion of irradiation according to generally accepted criteria. For tested criteria, ROC curves were drawn, determining cut-off points of 58 U/l for TPS and 500 pg/l for VEGF. For statistical calculations the U Mann-Whitney test was used.ResultsThe level of VEGF expression varied between groups of patients in certain stages of disease progression (stages 1 & 2 and stages 2 & 3). Statistically significant differences were found between group PR in stage 2 and a control group of healthy women. Entry levels of TPS rose with tumor advancement (in stages 2, 3 & 4) and were higher than in a group of healthy women. Detected differences were statistically significant.ConclusionsOnly pre-therapeutic TPS levels show definite differences between degrees of clinical advancement and also with early therapeutic effects. Comparatively higher levels of serum TPS were found in patients with the worst prognosis prior to treatment (group P) than in the control group. This difference is statistically significant. Pre-therapeutic VEGF levels showed statistically significant differences between early (I, II) and advanced (III) clinical stages of the tumor as well as some effects of therapy assessed immediately after completion of treatment (PR vs S)

Functional Lung MRI in Chronic Obstructive Pulmonary Disease: Comparison of T1 Mapping, Oxygen-Enhanced T1 Mapping and Dynamic Contrast Enhanced Perfusion

Purpose Monitoring of regional lung function in interventional COPD trials requires alternative end-points beyond global parameters such as FEV1. T1 relaxation times of the lung might allow to draw conclusions on tissue composition, blood volume and oxygen fraction. The aim of this study was to evaluate the potential value of lung Magnetic resonance imaging (MRI) with native and oxygen-enhanced T1 mapping for the assessment of COPD patients in comparison with contrast enhanced perfusion MRI. Materials and Methods 20 COPD patients (GOLD I-IV) underwent a coronal 2-dimensional inversion recovery snapshot flash sequence (8 slices/lung) at room air and during inhalation of pure oxygen, as well as dynamic contrast-enhanced first-pass perfusion imaging. Regional distribution of T1 at room air (T1), oxygen-induced T1 shortening (Delta T1) and peak enhancement were rated by 2 chest radiologists in consensus using a semi-quantitative 3-point scale in a zone-based approach. Results Abnormal T1 and Delta T1 were highly prevalent in the patient cohort. T1 and Delta T1 correlated positively with perfusion abnormalities (r = 0.81 and r = 0.80;p&0.001), and with each other (r = 0.80;p< 0.001). In GOLD stages I and II Delta T1 was normal in 16/29 lung zones with mildly abnormal perfusion (15/16 with abnormal T1). The extent of T1 (r = 0.45;p< 0.05), T1 (r = 0.52;p< 0.05) and perfusion abnormalities (r = 0.52;p< 0.05) showed a moderate correlation with GOLD stage. Conclusion Native and oxygen-enhanced T1 mapping correlated with lung perfusion deficits and severity of COPD. Under the assumption that T1 at room air correlates with the regional pulmonary blood pool and that oxygen-enhanced T1 reflects lung ventilation, both techniques in combination are principally suitable to characterize ventilation-perfusion imbalance. This appears valuable for the assessment of regional lung characteristics in COPD trials without administration of i. v. contrast