Representing Scott sets in algebraic settings

We prove that for every Scott set $S$ there are $S$-saturated real closed fields and models of Presburger arithmetic

Real closed exponential fields

In an extended abstract Ressayre considered real closed exponential fields and integer parts that respect the exponential function. He outlined a proof that every real closed exponential field has an exponential integer part. In the present paper, we give a detailed account of Ressayre's construction, which becomes canonical once we fix the real closed exponential field, a residue field section, and a well ordering of the field. The procedure is constructible over these objects; each step looks effective, but may require many steps. We produce an example of an exponential field $R$ with a residue field $k$ and a well ordering $<$ such that $D^c(R)$ is low and $k$ and $<$ are $\Delta^0_3$, and Ressayre's construction cannot be completed in $L_{\omega_1^{CK}}$.Comment: 24 page

Design and Evaluation of a Serious Game for the Training of Epilepsy Patients

Epilepsy patients often have inadequate epilepsy knowledge with negative consequences. Current training programs are on-site and do not offer the advantages of digital interventions regarding independence of time and place. Moreover, research on serious games is in its infancy for epilepsy. This paper presents EpiTales, a serious game for training epilepsy knowledge. We conducted a survey and analyzed existing interventions to gain understanding about the target group and educational concepts. To design EpiTales we followed the Octalysis game design framework. The effect was investigated by means of knowledge transfer using the method of a randomized controlled experiment. Additionally, usability tests were performed. Our results demonstrated an average relative knowledge increase of 51% and a higher perception of joy among players of the game. Nevertheless, the workbook used by the control group remains more effective. Future development should consider strengths of the workbook, while keeping the positively noted aspects of EpiTales

Mechanobiological Control of Circular Dorsal Ruffle Dynamics

Dynamic structures of polymerized actin play a crucial role in different cellular processes. These include different kinds of actin waves in a multitude of cell types, like Dictyostelium, neutrophiles, macrophages and fibroblasts. These actin waves are connected to a remodeling of the cytoskeleton, cell protrusion and migration as well as the uptake of extracellular fluids, but their specific functions are still debated. One type of them are circular dorsal ruffles (CDRs), actin-based ring-like membrane undulations on the dorsal cell side of fibroblasts, which emerge after growth factor stimulation. A large number of macromolecules were shown to be localized in CDRs and to be crucial for CDR formation. However, to date, the detailed signaling pathway and the underlying mechanism of CDR formation including their molecular main players remain unknown. Different studies on CDRs described them as actin waves in an excitable system or as wavefronts in a bistable regime between two stable states of actin. However, other studies focused on the interaction between actin polymerization and the cell membrane via the interplay of curved membrane protein complexes. This thesis further investigates the mechanism underlying CDR formation. For this study, the morphology of cells is an essential effector for the dynamics of actin waves. Their complexity and dynamical remodeling pose a challenge to the comparability of data. Therefore, in this work, fibroblasts are shaped into well-defined morphologies by seeding them on disk-like adhesion patterns made of fibronectin. This enables to identify long-range interactions between different CDRs combined with the influence of stochastic perturbations and thus uncovers the important role of the membrane tension in CDR dynamics. In combination with microfluidics, the response of the actin wave machinery to biochemical interference with drugs that target different parts of the actin machinery is investigated. The system allows systematical measurements of CDR velocities, periodicities and lifetimes that are performed to carry out a before/after comparison of the treated cells for examining the influence of actin, PIP3 and N-WASP. It is observed a dependence of CDR velocities, periodicities and lifetimes on the total amount of actin leading to the conclusion of a direct regulating role of actin in CDR formation and propagation. Furthermore, it is found that the actin nucleator N-WASP plays a fundamental role in CDR formation but not in CDR propagation. Numerical solutions of wavefronts in a bistable regime of a model system on an annulus domain resemble experimentally gained data and further uncover a dependence of the stimulation threshold for propagating wavefronts on the total actin concentration. The results underline the hypothesis that CDRs can be considered as wavefronts in a bistable regime between two stable states of actin

An 18-year record (1998-2016) of permafrost soil temperature, soil water content, and meteorological data from a high Arctic permafrost site Bayelva (Svalbard)

Since 1998 we record hourly data from the Bayelva site close to Ny-Alesund, on Spitsbergen Island in the Svalbard archipelago (78°551 N, 11°571 E), where continuous permafrost underlies the un- glaciated coastal areas. The West Spitsbergen Ocean Current, a branch of the North Atlantic Current, warms this area to an average air temperature of about −13 °C in January and +5 °C in July, and provides about 400 mm of precipitation annually, falling mostly as snow between September and May. Significant warming of air temperatures has been detected since 1960, which is generally attributed to changes in the radiation budget and in atmospheric circulation. This warming is also reflected in the permafrost temperatures, as recorded from boreholes as well as increased active layer thaw depths. The scientific goal is to establish a long term- permafrost observational site to investigate the observed warming of permafrost and potential causes. At the site, weather components (radiation components, temperature, humidity, wind speed and direction, snow) and soil temperature and moisture in the seasonally thawing surface layer. In 2007, additional instruments were added: an eddy covariance system and a 10 m permafrost temperature profile. In 2012, this site was equipped with a 220 V power supply and data transfer cables that are buried in the soil. Data are transferred hourly to Potsdam and loggers and sensors can be accessed and programmed remotely from AWI. Due to this major improvement, we obtained a data record without gaps since 2012. Thus, this site is included as validation site in satellite missions, for example in NASA’s soil moisture active passive mission (SMAP). We give an overview of the available data, as well as the processing and cleaning routines that are applied