427 research outputs found

    Design and Implementation of the Double Chooz Muon Veto

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    Im Double Chooz-Experiment wurde der dritte Mischungswinkel Theta_{13} der PMNS-Matrix, die die Oszillationen von Neutrinos beschreibt, mit hoher Genauigkeit vermessen. Hierzu war die präzise Überwachung des durch kosmische Myonen induzierten Untergrundes zwingende Voraussetzung. Die Arbeit beschreibt die Monte-Carlo-Simulationsgestützte Entwicklung des inneren Myon-Vetos sowie Konstruktion und Aufbau des Teildetektors. Ebenso enthält sie eine Analyse der ersten Datennahmeperiode im Hinblick auf myonischen Untergrund inklusive kosmogener Radioisotope wie Li-9, die einen nur schwer von echten Neutrinoereignissen zu unterscheidenden Untergrund verursachen und im Vergleich zur Myonrate im Detektor hohe Lebensdauern haben.The Double Chooz experiment measured the third mixing angle Theta_{13} as found in the PMNS matrix of neutrino oscillation theory with high precision. To achieve this, an accurate knowledge of background rates and signatures induced by cosmic muons was mandatory. In this thesis, the Monte-Carlo based simulation aided design of the Inner Muon Veto as well as construction and setup of the detector subsystem are described. It also contains an analysis of the first data taking period focussing on muon induced background, including cosmogenic radioisotopes like Li-9, whose event signature in the detector is practically undistinguishable from real neutrino events and which have a life time that is large in comparison to muon rates within the detector

    Weather on the Nearest Brown Dwarfs: Resolved Simultaneous Multi-Wavelength Variability Monitoring of WISE J104915.57-531906.1AB

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    We present two epochs of MPG/ESO 2.2m GROND simultaneous 6-band (rizJHKr'i'z'JHK) photometric monitoring of the closest known L/T transition brown dwarf binary WISE J104915.57-531906.1AB. We report here the first resolved variability monitoring of both the T0.5 and L7.5 components. We obtained 4 hours of focused observations on the night of UT 2013-04-22, as well as 4 hours of defocused (unresolved) observations on the night of UT 2013-04-16. We note a number of robust trends in our light curves. The rr' and ii' light curves appear to be anticorrelated with zz' and HH for the T0.5 component and in the unresolved lightcurve. In the defocused dataset, JJ appears correlated with zz' and HH and anticorrelated with rr' and ii', while in the focused dataset we measure no variability for JJ at the level of our photometric precision, likely due to evolving weather phenomena. In our focused T0.5 component lightcurve, the KK band lightcurve displays a significant phase offset relative to both HH and zz'. We argue that the measured phase offsets are correlated with atmospheric pressure probed at each band, as estimated from 1D atmospheric models. We also report low-amplitude variability in ii' and zz' intrinsic to the L7.5 component.Comment: 14 pages, 5 figures, accepted to ApJ Letter

    Precast concrete floor support and diaphragm action

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    Experimental research, engineering analysis and theoretical developments comprise a study in which various interactions between ductile moment resisting frames and precast prestressed hollow core flooring have been examined. The most critical interaction tested involves support behaviour, and the ability of reinforcing details to provide control against loss of support and possible catastrophic flooring collapse under dilation effects. Plastic hinge dilation, also known as elongation or growth, is an inherent property of ductile concrete members when subjected to cyclic plastic deformations. Hence, the performance of floor support details is enveloped by the general design philosophy of seismic resisting structures. In the experimental phase, emphasis was placed on testing support construction joints from contemporary building practice, for direct comparison with special support tie details of known capabilities. The contemporary details were found to exhibit seriously flawed behaviour under monotonic and cyclic loading regimes. Corroborative experiments were undertaken to establish direct shear capacities between typical composite bond surfaces. In particular, these tests addressed the discrepancy that has emerged between direct shear and shear flow strengths. Also, the continuity response of conventional and proposed support detail types was examined. A composite section model was analysed to demonstrate the likely influence of prestressing steel on beam bending strength within a ductile frame environment. Likewise, the probable effects of prestressing steel on beam plastic hinge development were examined, but on a more theoretical basis. Other elements of theory have been presented. These mainly concern the general topic of elastic-plastic response in reinforced concrete elements. The particular focus of this work has been to demonstrate a rational basis to stiffness transition and plastic buckling analysis. The important role of stiffness degradation in dynamic analysis has also been examined. Although ductile moment resisting concrete frames have been emphasised, it is considered that the findings of this thesis are applicable to other structural systems, such as dry joint "hybrid" precast concrete frames and spring connected steel frame structures

    The INF Treaty of 1987

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    Der von Ronald Reagan und Michail Gorbatschow am 8. Dezember 1987 unterzeichnete »Intermediate-Range Nuclear Forces Treaty«, kurz INF-Vertrag, stellte einen Meilenstein der nuklearen Abrüstungsverhandlungen zwischen den Vereinigten Staaten von Amerika und der Sowjetunion dar. Im Jahr 2019 wurde er von Russland und den USA gekündigt. Der englischsprachige Band untersucht die Vorgeschichte des Abkommens, dessen Implementierung und Folgen sowohl in den beiden Supermächten als auch in den mit ihnen verbündeten Staaten. Er ist damit die erste umfassende Darstellung eines der wichtigsten Abrüstungsabkommen der jüngsten Zeit

    Vaccination with designed neopeptides induces intratumoral, cross-reactive CD4+ T cell responses in glioblastoma

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    Purpose: The low mutational load of some cancers is considered one reason for the difficulties to develop effective tumor vaccines. To overcome this problem, we developed a strategy to design neopeptides through single amino acid mutation to enhance their immunogenicity. Experimental Design: Exome- and RNA sequencing as well as in silico HLA-binding predictions to autologous HLA molecules were used to identify candidate neopeptides. Subsequently, in silico HLA-anchor placements were used to deduce putative T cell receptor contacts of peptides. Single amino acids of TCR contacting residues were then mutated by amino acid replacements. Overall, 175 peptides were synthesized and sets of 25 each containing both peptides designed to bind to HLA class I and II molecules applied in the vaccination. Upon development of a tumor recurrence, the tumor-infiltrating lymphocytes (TILs) were characterized in detail both at the bulk and clonal level. Results: The immune response of peripheral blood T cells to vaccine peptides, including natural peptides and designed neopeptides, gradually increased with repetitive vaccination, but remained low. In contrast, at the time of tumor recurrence, CD8+ TILs and CD4+ TILs responded to 45% and 100% respectively of the vaccine peptides. Further, TIL-derived CD4+ T cell clones showed strong responses and tumor cell lysis not only against the designed neopeptide but also against the unmutated natural peptides of the tumor. Conclusions: Turning tumor self-peptides into foreign antigens by introduction of designed mutations is a promising strategy to induce strong intratumoral CD4+ T cell responses in a cold tumor like glioblastoma

    Assessing quality of life in a clinical study on heart rehabilitation patients: how well do value sets based on given or experienced health states reflect patients' valuations?

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    Background: Quality of life as an endpoint in a clinical study may be sensitive to the value set used to derive a single score. Focusing on patients' actual valuations in a clinical study, we compare different value sets for the EQ-5D-3L and assess how well they reproduce patients' reported results. Methods: A clinical study comparing inpatient (n = 98) and outpatient (n = 47) rehabilitation of patients after an acute coronary event is re-analyzed. Value sets include: 1. Given health states and time-trade-off valuation (GHS-TTO) rendering economic utilities;2. Experienced health states and valuation by visual analog scale (EHS-VAS). Valuations are compared with patient-reported VAS rating. Accuracy is assessed by mean absolute error (MAE) and by Pearson's correlation.. External validity is tested by correlation with established MacNew global scores. Drivers of differences between value sets and VAS are analyzed using repeated measures regression. Results: EHS-VAS had smaller MAEs and higher. in all patients and in the inpatient group, and correlated best with MacNew global score. Quality-adjusted survival was more accurately reflected by EHS-VAS. Younger, better educated patients reported lower VAS at admission than the EHS-based value set. EHS-based estimates were mostly able to reproduce patient-reported valuation. Economic utility measurement is conceptually different, produced results less strongly related to patients' reports, and resulted in about 20 % longer quality-adjusted survival. Conclusion: Decision makers should take into account the impact of choosing value sets on effectiveness results. For transferring the results of heart rehabilitation patients from another country or from another valuation method, the EHS-based value set offers a promising estimation option for those decision makers who prioritize patient-reported valuation. Yet, EHS-based estimates may not fully reflect patient-reported VAS in all situations

    Environmental considerations and current status of grouping and regulation of engineered nanomaterials

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    This article reviews the current status of nanotechnology with emphasis on application and related environmental considerations as well as legislation. Application and analysis of nanomaterials in infrastructure (construction, building coatings, and water treatment) is discussed, and in particular nanomaterial release during the lifecycle of these applications. Moreover, possible grouping approaches with regard to ecotoxicological and toxicological properties, and the fate of nanomaterials in the environment are evaluated. In terms of potential exposure, the opportunities that arise from leveraging advances in several key areas, such as water treatment and construction are addressed. Additionally, this review describes challenges with regard to the European Commission’s definition of ‘nanomaterial’. The revised REACH information requirements, intended to enable a comprehensive risk assessment of nanomaterials, are outlined
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