Detecting directional coupling in the human epileptic brain: Limitations and potential pitfalls

We study directional relationships—in the driver-responder sense—in networks of coupled nonlinear oscillators using a phase modeling approach. Specifically, we focus on the identification of drivers in clusters with varying levels of synchrony, mimicking dynamical interactions between the seizure generating region (epileptic focus) and other brain structures. We demonstrate numerically that such an identification is not always possible in a reliable manner. Using the same analysis techniques as in model systems, we study multichannel electroencephalographic recordings from two patients suffering from focal epilepsy. Our findings demonstrate that—depending on the degree of intracluster synchrony—certain subsystems can spuriously appear to be driving others, which should be taken into account when analyzing field data with unknown underlying dynamics

"(Weitergeleitet von Journalistin)": The Gendered Presentation of Professions on Wikipedia

Previous research has shown the existence of gender biases in the depiction of professions and occupations in search engine results. Such an unbalanced presentation might just as likely occur on Wikipedia, one of the most popular knowledge resources on the Web, since the encyclopedia has already been found to exhibit such tendencies in past studies. Under this premise, our work assesses gender bias with respect to the content of German Wikipedia articles about professions and occupations along three dimensions: used male vs. female titles (and redirects), included images of persons, and names of professionals mentioned in the articles. We further use German labor market data to assess the potential misrepresentation of a gender for each specific profession. Our findings in fact provide evidence for systematic over-representation of men on all three dimensions. For instance, for professional fields dominated by females, the respective articles on average still feature almost two times more images of men; and in the mean, 83% of the mentioned names of professionals were male and only 17% female.Comment: In the 9th International ACM Web Science Conference 2017 (WebSci'17), June 25-28, 2017, Troy, NY, USA. Based on the results of the thesis: arXiv:1702.0082

An Anti-Colonial Empire? Non-European Perspectives on the Weimar Republic and the German Dream of Empire (1919–1930s)

Der Erste Weltkrieg beseitigte nicht nur Deutschlands Status als Kolonialmacht. Er bewegte auch die deutsche Regierung dazu, mit antikolonialen Bewegungen in der ganzen Welt zu kooperieren, um die Imperien ihrer Kriegsgegner zu destabilisieren. Es nimmt darum nicht Wunder, dass antikoloniale Intellektuelle nach dem Krieg ihre Hoffnungen auf das scheinbar dekolonisierte und potenziell antikoloniale Deutschland setzten. Diese Erwartung gab der Weimarer Republik die Gelegenheit, sich als antikoloniale Macht zu etablieren und gleichzeitig ihren indirekten Einfluss auf die nicht-europäische Welt auszudehnen. Dieser Artikel fragt, warum das Deutschland der Zwischenkriegszeit das Angebot ablehnte, sich als „antikoloniales Imperium“ bei den Siegern von 1919 zu revanchieren. Entgegen gängigen Interpretationen wird dabei gezeigt, dass selbst Revanchisten darauf vertrauten, weiterhin eine europäische Kolonialmacht zu bleiben. Zudem verhinderten rassistische Einbürgerungsgesetze einen praktischen Wandel Deutschlands zur „antikolonialen Metropole“

Snow White and Rose Red: Studies on the contrasting evolutionary trajectories of the genera Leucanthemum Mill. and Rhodanthemum B.H. Wilcox & al. (Compositae, Anthemideae)

Plant systematics, the study of taxonomy, phylogeny and evolutionary processes in plants has undergone considerable progress in the last decades. The application of modern molecular approaches and DNA-sequencing techniques in the field has led to an improved inventory of biodiversity and a better understanding of evolutionary processes shaping the biological diversity on our planet. The increased availability of molecular and genomic data has particularly facilitated the investigation of shallowly diverged and taxonomically complex taxon-groups, which is challenging due to minor morphological differences, low genetic differentiation and/or hybridization among taxa. The present thesis investigates species delimitation, hybridization and polyploidization in the recently diverged genera Leucanthemum Mill. and Rhodanthemum B.H. Wilcox & al. of the subtribe Leucantheminae K.Bremer & Humphries (Compositae, Anthemideae) by applying Sanger-, 454-pyro-, and restriction site associated DNA (RAD) sequencing, as well as AFLP-fingerprinting and morphometric analyses. The first two parts are focusing on species delimitation and hybridization in the closely-knit taxon groups around L. ageratifolium Pau and R. arundanum B.H. Wilcox & al., respectively. Various analyses based on AFLP fingerprinting, RADseq and multi-locus sequence data demonstrate that the robustness of species delimitation results is considerably influenced by the intensity of hybridization among species and the number of hybrid individuals included. Therefore, a step-by-step approach is performed in both studies, with an initially step of identification and subsequent removal of hybrid individuals, followed by application of different species-delimitation methods. This strategy results in the reliable identification of independent species, subspecies and nothospecies in both taxonomically complex plant groups. The third part of the present thesis compares the contrasting evolutionary trajectories of diploid representatives of both genera in a more comprehensive phylogenetic study. Specific hypotheses for the formation of polyploids in plants are proposed and evaluated to find factors that promote polyploidization in certain plant groups (e.g., Leucanthemum) and not in others (e.g., Rhodanthemum). Multi-locus sequence data from 127 accessions of the subtribe Leucantheminae unveil a significantly higher genetic divergence and hybridization signal among diploid lineages of Leucanthemum compared to Rhodanthemum, in spite of a similar crown age and diversification pattern during the Quaternary. The study demonstrates the importance of genetic differentiation among diploid progenitors and their concurrent affinity for natural hybridization for the formation of a polyploid complex. Furthermore, the role of climate-induced range overlaps on hybridization and polyploid speciation during the Quaternary is discussed

miR-200c sensitizes breast cancer cells to doxorubicin treatment by decreasing TrkB and Bmi1 expression.

Acquired resistance to classical chemotherapeutics is a major obstacle in cancer treatment. Doxorubicin is frequently used in breast cancer therapy either as single-agent or in combination with other drugs like docetaxel and cyclophosphamide. All these chemotherapies have in common that they are administered sequentially and often result in chemoresistance. Here, we mimicked this pulse therapy of breast cancer patients in an in vitro cell culture model, where the epithelial breast cancer cell line BT474 was sequentially treated with doxorubicin for several treatment cycles. In consequence, we obtained chemoresistant cells displaying a mesenchymal-like phenotype with decreased levels of miR-200c. To investigate the involvement of miR-200c in resistance formation, we inhibited and overexpressed miR-200c in different cell lines. Thereby, the cells were rendered more resistant or susceptible to doxorubicin treatment. Moreover, the receptor tyrosine kinase TrkB and the transcriptional repressor Bmi1 were identified as miR-200c targets mediating the drug resistance. Hence, we provide a mechanism of acquired resistance to doxorubicin that is caused by the loss of miR-200c. Along with this, our study demonstrates the complex network of microRNA mediated chemoresistance highlighting the challenges in cancer therapy and the importance of novel microRNA-modulating anticancer agents