Time ordered perturbation theory for non-local interactions; applications to NCQFT

In the past decades, time ordered perturbation theory was very successful in describing relativistic scattering processes. It was developed for local quantum field theories. However, there are field theories which are governed by non-local interactions, for example non-commutative quantum field theory (NCQFT). Filk (Phys. Lett. B 376 (1996) 53) first studied NCQFT perturbatively obtaining the usual Feynman propagator and additional phase factors as the basic elements of perturbation theory. However, this treatment is only applicable for cases, where the deformation of space-time does not involve time. Thus, we generalize Filk's approach in two ways: First, we study non-local interactions of a very general type able to embed NCQFT. And second, we also include the case, where non-locality involves time. A few applications of the obtained formalism will also be discussed.Comment: 21 pages, 2 figure

Adjoint-based calibration of nonlinear stochastic differential equations

To study the nonlinear properties of complex natural phenomena, the evolution of the quantity of interest can be often represented by systems of coupled nonlinear stochastic differential equations (SDEs). These SDEs typically contain several parameters which have to be chosen carefully to match the experimental data and to validate the effectiveness of the model. In the present paper the calibration of these parameters is described by nonlinear SDE-constrained optimization problems. In the optimize-before-discretize setting a rigorous analysis is carried out to ensure the existence of optimal solutions and to derive necessary first-order optimality conditions. For the numerical solution a Monte-Carlo method is applied using parallelization strategies to compensate for the high computational time. In the numerical examples an Ornstein-Uhlenbeck and a stochastic Prandtl-Tomlinson bath model are considered

The impact of the AO foundation on fracture care : an evaluation of 60 years AO foundation

Objectives Sixty years ago, the Association of Osteosynthesis (AO) was founded with the aim to improve fracture treatment and has since grown into one of the largest medical associations worldwide. Aim of this study was to evaluate AO's impact on science, education, patient care and the MedTech business. Design/methods Impact evaluations were conducted as appropriate for the individual domains: Impact on science was measured by analyzing citation frequencies of publications promoted by AO. Impact on education was evaluated by analyzing the evolution of number and location of AO courses. Impact on patient care was evaluated with a health economic model analyzing cost changes and years of life gained through the introduction of osteosynthesis in 17 high-income countries (HICs). Impact on MedTech business was evaluated by analyzing sales data of AO-associated products. Results Thirty-five AO papers and 2 major AO textbooks are cited at remarkable frequencies in high ranking journals with up to 2000 citations/year. The number of AO courses steadily increased with a total of 645'000 participants, 20‘000 teaching days and 2‘500 volunteer faculty members so far. The introduction of osteosynthesis saved at least 925 billion Swiss Francs [CHF] in the 17 HICs analyzed and had an impact on avoiding premature deaths comparable to the use of antihypertensive drugs. AO-associated products generated sales of 55 billion CHF. Conclusion AO's impact on science, education, patient care, and the MedTech business was significant because AO addressed hitherto unmet needs by combining activities that mutually enriched and reinforced each other

Miocene vegetation and climate in the eastern North Sea Basin, onshore Denmark, compared to the present

Despite often being referred to as a ‘coolhouse climate’, the climate during the Miocene (23.03–5.33 Ma) was overall humid, warm and temperate. It was paced by orbitally driven cooler periods (the Oligocene–Miocene Transition and Mi-events) overprinted by a climatic optimum. Global cooling during the Late Miocene brought more arid conditions with climate seasonality, which varied across western Eurasia. Sedimentary archives from onshore Denmark comprise shallow marine siliciclastic deposits and discrete brown coal layers. Hence, they allow us to infer past climates and environments using both marine and terrestrial fossils. The backbone for Miocene stratigraphy and palaeoclimate reconstruction in the eastern North Sea Basin (present-day Denmark) is the Sønder (Sdr.) Vium sediment core, which penetrates a shallow marine succession and spans an interval from c. 22 to 8 Ma. Here, we present an improved age model for the core. During the Miocene, forested lowlands predominated in the eastern North Sea Basin. Coastal areas included rich riparian landscapes and delta areas of lignite-forming swamp forest. Compilations of existing proxy records (pollen, spores, leaves, plant fragments and the organic biomarkers alkenones and membrane lipids) collectively show that the climate here was warm and moist during the Early and Middle Miocene, while the Late Miocene was characterised by climate cooling and modernisation of the vegetation. The interval preceding the Miocene Climatic Optimum was already warm and moist, and the onset was not characterised by a significant increase in temperature and precipitation. Instead, the palynoflora indicates homogeneous vegetation and only a weak signal of warming shown by a minor increase of, for example, sabaloid palms and Mastixiaceae

Building in Hongkong. Field Excursion of the Department of Civil Engineering of the HTWG Konstanz 2012

Hongkong steht als Welthandelsmetropole auch für Superlative des Bauens. Dies gilt für die in britischer Zeit errichteten Bauten, aber auch für die nach der Übergabe an China entstandenen Hochhäuser und Brückenbauwerke. Der Exkursionsbericht der Fakultät Bauingenieurwesen der HTWG Konstanz gibt einen Eindruck von diesen Aktivitäten. Er schildert Brücken- und Hochhausbauten, Tunnelbaustellen und die Baustelle eines Klärschlammverbrennungswerks, die während einer Exkursionswoche im September 2012 besichtigt wurden. Darüber hinaus gibt er einen Einblick in die wirtschaftliche Dynamik der Stadt.As a global metropolis Hongkong also stands for outstanding building activities. The report depicts the impressions during a student field excursion of the Faculty of Civil Engineering of the University of Applied Sciences Konstanz, Germany, to construction sites in Hongkong in September 2012

German federal-state-wide seroprevalence study of 1st SARS-CoV-2 pandemic wave shows importance of long-term antibody test performance

Background Reliable data on the adult SARS-CoV-2 infection fatality rate in Germany are still scarce. We performed a federal state-wide cross-sectional seroprevalence study named SaarCoPS, that is representative for the adult population including elderly individuals and nursing home residents in the Saarland. Methods Serum was collected from 2940 adults via stationary or mobile teams during the 1st pandemic wave steady state period. We selected an antibody test system with maximal specificity, also excluding seroreversion effects due to a high longitudinal test performance. For the calculations of infection and fatality rates, we accounted for the delays of seroconversion and death after infection. Results Using a highly specific total antibody test detecting anti-SARS-CoV-2 responses over more than 180 days, we estimate an adult infection rate of 1.02% (95% CI: [0.64; 1.44]), an underreporting rate of 2.68-fold (95% CI: [1.68; 3.79]) and infection fatality rates of 2.09% (95% CI: (1.48; 3.32]) or 0.36% (95% CI: [0.25; 0.59]) in all adults including elderly individuals, or adults younger than 70 years, respectively. Conclusion The study highlights the importance of study design and test performance for seroprevalence studies, particularly when seroprevalences are low. Our results provide a valuable baseline for evaluation of future pandemic dynamics and impact of public health measures on virus spread and human health in comparison to neighbouring countries such as Luxembourg or France

Impact of osteosynthesis in fracture care : a cost comparison study

Aim: To estimate the health economic impact of osteosynthesis (OS) in fracture care over six decades in 17 high-income countries. Patients & methods: Applying a decision tree model, we assumed a hypothetical absence of OS and compared OS (intervention) with conservative treatment (CONS; comparator). We included patients with femur, tibia and radius fractures (age <65 years) and for proximal femur fractures also elderly patients (≥70 years). Results: We estimated savings in direct and indirect costs of 855 billion Swiss francs in the working age population in addition to 4.6 million years of life gained. In the elderly population, 69 billion Swiss francs were saved in direct costs of proximal femur fractures in addition to 73 million years of life gained. Conclusion: OS contributed to maximize health gains of society

Fast extraction of neuron morphologies from large-scale SBFSEM image stacks

Neuron morphology is frequently used to classify cell-types in the mammalian cortex. Apart from the shape of the soma and the axonal projections, morphological classification is largely defined by the dendrites of a neuron and their subcellular compartments, referred to as dendritic spines. The dimensions of a neuron’s dendritic compartment, including its spines, is also a major determinant of the passive and active electrical excitability of dendrites. Furthermore, the dimensions of dendritic branches and spines change during postnatal development and, possibly, following some types of neuronal activity patterns, changes depending on the activity of a neuron. Due to their small size, accurate quantitation of spine number and structure is difficult to achieve (Larkman, J Comp Neurol 306:332, 1991). Here we follow an analysis approach using high-resolution EM techniques. Serial block-face scanning electron microscopy (SBFSEM) enables automated imaging of large specimen volumes at high resolution. The large data sets generated by this technique make manual reconstruction of neuronal structure laborious. Here we present NeuroStruct, a reconstruction environment developed for fast and automated analysis of large SBFSEM data sets containing individual stained neurons using optimized algorithms for CPU and GPU hardware. NeuroStruct is based on 3D operators and integrates image information from image stacks of individual neurons filled with biocytin and stained with osmium tetroxide. The focus of the presented work is the reconstruction of dendritic branches with detailed representation of spines. NeuroStruct delivers both a 3D surface model of the reconstructed structures and a 1D geometrical model corresponding to the skeleton of the reconstructed structures. Both representations are a prerequisite for analysis of morphological characteristics and simulation signalling within a neuron that capture the influence of spines