235 research outputs found

    On the numerical range of sectorial forms

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    We provide a sharp and optimal generic bound for the angle of the sectorial form associated to a non-symmetric second-order elliptic differential operator with various boundary conditions. Consequently this gives an, in general, sharper H∞-angle for the H∞-calculus on Lp for all p ∈ (1, ∞) if the coefficients are real valued

    Divergence-free reconstruction operators for pressure-robust Stokes discretizations with continuous pressure finite elements

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    Classical inf-sup stable mixed finite elements for the incompressible (Navier--)Stokes equations are not pressure-robust, i.e., their velocity errors depend on the continuous pressure. How-ever, a modification only in the right hand side of a Stokes discretization is able to reestablish pressure-robustness, as shown recently for several inf-sup stable Stokes elements with discontinuous discrete pressures. In this contribution, this idea is extended to low and high order Taylor--Hood and mini elements, which have continuous discrete pressures. For the modification of the right hand side a velocity reconstruction operator is constructed that maps discretely divergence-free test functions to exactly divergence-free ones. The reconstruction is based on local H(div)-conforming flux equilibration on vertex patches, and fulfills certain orthogonality properties to provide consistency and optimal a-priori error estimates. Numerical examples for the incompressible Stokes and Navier--Stokes equations confirm that the new pressure-robust Taylor--Hood and mini elements converge with optimal order and outperform signi--cantly the classical versions of those elements when the continuous pressure is comparably large

    Innenentwicklung durch Visualisierung und Partizipation

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    Mithilfe des vom BMBF geförderten Forschungsprojekts AktVis soll durch die Entwicklung und Erprobung neuer praxisnaher Entscheidungshilfen sowie interaktiver Planungsinstrumente eine aktive Innenentwicklung unterstützt werden. Denn trotz des breiten Konsens, angefangen bei der Wissenschaft bis hin zur kommunalen Praxis, hinsichtlich der ökologischen, ökonomischen und sozialen Notwendigkeit einer Reduzierung der Flächeninanspruchnahme und Fokussierung städtebaulicher Entwicklungen auf den Siedlungskörper, bestehen weiterhin Defizite in der faktischen Umsetzung. Insbesondere der Zugriff auf Grundstücke, die im Privateigentum stehen, erweist sich als schwierig. Für eine erfolgreiche Aktivierung von Innenentwicklungspotenzialen werden daher die Stakeholder und Schlüsselakteure, also die Eigentümer, Bürger und lokalen Gruppen, in den Kommunen als außerordentlich relevant angesehen. Diese sollen durch eine intensive Einbindung und die aktive Mitgestaltung der Ortskerne für Projekte mobilisiert werden. Mithilfe eines Multitouch-Tisches sowie eines WebGIS werden die Möglichkeiten des selbstbestimmten Editierens von Inhalten und der Veränderungen der Ortschaften gegeben. Die dreidimensionale Visualisierung mit unterschiedlichen Tools soll zur Aktivierung von Potenzialen beitragen

    Transapical aortic valve implantation with a self-expanding anatomically oriented valve

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    Aims The Medtronic Engager™ aortic valve bioprosthesis is a self-expanding valve with support arms facilitating anatomically correct positioning and axial fixation. Valve leaflets, made of bovine pericardium, are mounted on a Nitinol frame. Here, we report the first in man study with this new implant (Trial Identifier NCT00677638). Methods and results Thirty patients (mean age 83.4 ± 3.8 years; 83% female) with tricuspid aortic valve stenosis were included in the study. Mean logistic EuroSCORE was 23.4 ± 11.9. Mean aortic annulus diameter was 21.8 ± 1.4 mm. For this study, the Engager was available in only one size (23 mm), to fit aortic annuli of 19-23 mm. Standard transapical valve implantation was performed using predilation of the aortic valve and rapid ventricular pacing during ballon valvuloplasty and most valve deployments. Accurate valve placement was achieved in 29/30 cases (97%). Post-implant peak-to-peak gradient was 13.3 ± 9.3 mmHg. In 80% of the patients, no more than grade I paravalvular leakage was observed, in 13% grades I-II and in 3% grade II. Three patients (10%) required permanent pacemaker implantation for higher-degree or complete atrioventricular block. Four dissections (13%) occurred during positioning of the valve and were treated surgically in three cases. Thirty-day and in-hospital mortality were 20% and 23%, respectively, and 6-month survival was 56.7%. No structural failure occurred for up to 1 year. Conclusion This series established the feasibility of implanting a novel self-expanding transapical aortic valve prosthesis predictably into an anatomically correct position. Observed complications led to complete redesign of the delivery system for upcoming clinical studies with the goal of establishing safety and performanc

    Технико-экономические и экологические аспекты утилизация шламов, содержащих соединения цинка

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    По причине токсичности перед сбросом в водоемы ионы цинка выделяются из сточных вод в виде твердых соединений, которые осаждаются в виде шлама в прудах-накопителях. Приведены данные по количественному и качественному составам шлама в накопителеотстойнике предприятия по производству вискозного волокна. Отмечено, что такой накопитель в г. Красноярске является техногенным образованием содержащем ценное сырье - цинк. Поэтому необходима разработка и внедрение технологий переработки и утилизации цинксодержащих шламов различных производств.Zinc ions are toxic and they are isolated from sewage in the form of solid compounds before discharge into water bodies. Precipitation occurs in the form of slime in storage ponds. Data on the quantitative and qualitative composition of the sludge in the reservoir-settler of an enterprise for the production of viscose fiber are given. It is noted that such a storage facility in Krasnoyarsk is a technogenic for mation containing valuable raw materials - zinc. Therefore, it is necessary to develop and implement technologies for processing and utilization of zinc-containing slurries of various industries

    KiDS-1000 cosmology: Combined second- and third-order shear statistics

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    This paper performs the first cosmological parameter analysis of the KiDS-1000 data with second- and third-order shear statistics. This work builds on a series of papers that describe the roadmap to third-order shear statistics. We derive and test a combined model of the second-order shear statistic, namely the COSEBIs and the third-order aperture mass statistics Map3\langle M_\mathrm{ap}^3\rangle in a tomographic set-up. We validate our pipeline with NN-body simulations that mock the fourth Kilo Degree survey data release. To model the second- and third-order statistics, we use the latest version of \textsc{HMcode2020} for the power spectrum and \textsc{BiHalofit} for the bispectrum. Furthermore, we use an analytic description to model intrinsic alignments and hydro-dynamical simulations to model the effect of baryonic feedback processes. Lastly, we decreased the dimension of the data vector significantly by considering for the Map3\langle M_\mathrm{ap}^3\rangle part of the data vector only equal smoothing radii, making a data analysis of the fourth Kilo Degree survey data release using a combined analysis of COSEBIs third-order shear statistic possible. We first validate the accuracy of our modelling by analysing a noise-free mock data vector assuming the KiDS-1000 error budget, finding a shift in the maximum-a-posterior of the matter density parameter ΔΩm<0.02σΩm\Delta \Omega_m< 0.02\, \sigma_{\Omega_m} and of the structure growth parameter ΔS8<0.05σS8\Delta S_8 < 0.05\, \sigma_{S_8}. Lastly, we performed the first KiDS-1000 cosmological analysis using a combined analysis of second- and third-order shear statistics, where we constrained Ωm=0.2480.055+0.062\Omega_m=0.248^{+0.062}_{-0.055} and S8=σ8Ωm/0.3=0.772±0.022S_8=\sigma_8\sqrt{\Omega_m/0.3}=0.772\pm0.022. The geometric average on the errors of Ωm\Omega_\mathrm{m} and S8S_8 of the combined statistics increased compared to the second-order statistic by 2.2.Comment: 19 pages, 15 figures. Updated version with arXiv ID of our companion paper Porth et at. 202
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