Relativistic Energy-consistent Pseudopotentials for f-Elements

In this thesis relativistic energy-consistent pseudopotentials (PPs) for f-elements have been adjusted. The PP approach restricts the explicit calculations to the chemically relevant valence electron system and implicitly includes relativistic effects by means of a simple parameterization. Thus, it is a commonly used approximation to study molecules containing f-elements, where the large number of electrons and the significant relativistic effects are the main obstacles. Even difficulties due to open shells can be avoided, if these are included in the core, as it is the case for f-in-core PPs. However, if the f shell is not treated explicitly, one PP for each oxidation state has to be adjusted. This thesis completes the already existing quasirelativistic f-in-core PPs, i.e. 5f-in-core PPs for di- (Pu-No), tetra- (Th-Cf), penta- (Pa-Am), and hexavalent (U-Am) actinides and 4f-in-core PPs for tetravalent (Ce-Nd, Tb, Dy) lanthanides are presented. Corresponding molecular basis sets of polarized valence double- to quadruple-zeta quality have been derived. Smaller basis sets suitable for crystal calculations form subsets of these basis sets. Furthermore, core-polarization potentials for di-, tri-, and tetravalent actinides have been adjusted to account for the neglect of static and dynamic core-polarization. Atomic test calculations on actinide ionization potentials as well as molecular test calculations on actinide and lanthanide fluorides using the Hartree-Fock and coupled cluster method show satisfactory agreement with calculations using f-in-valence PPs and experimental data, respectively, except for plutonium difluoride and neptunium, plutonium, and americium hexafluoride. While for plutonium difluoride the large deviations are due to the fact that for plutonium the divalent oxidation state is not stable, in the hexavalent case the 5f-in-core approximation seems to reach its limitations except for uranium. Moreover, the 5f-in-core PPs are successfully applied to actinocenes, actinyl ions, and uranyl(VI) complexes. Thus, the f-in-core PPs should be an efficient computational tool for those compounds, where the f orbitals do not participate significantly in chemical bonding. In addition to the quasirelativistic f-in-core PPs, the recently adjusted 5f-in-valence uranium PP including scalar-relativistic effects as well as spin-orbit coupling have been tested by calculating the fine-structure splittings of U5+ and U4+. These test calculations gave reliable results and thus confirm earlier benchmark calculations on uranium monohydride

Influence of Increasing Nutrient Availability on Fern and Lycophyte Diversity

Increased nutrient supply can have drastic effects on natural ecosystems, especially in naturally nutrient-poor ones such as most tropical rainforests. Many studies have focused on the reaction of trees to fertilization, but little is known about herbaceous plants. Ferns are a particularly common group in tropical forests, spanning all vegetation types and zones. Here, we assess how seven years of moderate addition of nitrogen (N), phosphorus (P), and N+P along an elevational gradient (1000–3000 m) have impacted richness and composition of fern and lycophyte assemblages in tropical montane rain forests growing on naturally nutrient deficient soils in the Ecuadorian Andes. We found that fertilization does not affect overall species richness, but that there were strong differences in species abundances (∼60% of species), both negative and positive, that were apparently related to the systematic affiliations and ecological properties of the affected species. These diverse responses of ferns to fertilization provide insight into the sensitivity and complexity of the relationships of nutrient availability and community composition in tropical forests

Introgressive hybridisation between domestic pigs (<i>Sus scrofa domesticus</i>) and endemic Corsican wild boars (<i>S. s. meridionalis</i>):Effects of human-mediated interventions

Owing to the intensified domestication process with artificial trait selection, introgressive hybridisation between domestic and wild species poses a management problem. Traditional free-range livestock husbandry, as practiced in Corsica and Sardinia, is known to facilitate hybridisation between wild boars and domestic pigs (Sus scrofa). Here, we assessed the genetic distinctness and genome-wide domestic pig ancestry levels of the Corsican wild boar subspecies S. s. meridionalis, with reference to its Sardinian conspecifics, employing a genome-wide single nucleotide polymorphism (SNP) assay and mitochondrial control region (mtCR) haplotypes. We also assessed the reliance of morphological criteria and the melanocortin-1 receptor (MC1R) coat colour gene to identify individuals with domestic introgression. While Corsican wild boars showed closest affinity to Sardinian and Italian wild boars compared to other European populations based on principal component analysis, the observation of previously undescribed mtCR haplotypes and high levels of nuclear divergence (Weir's θ > 0.14) highlighted the genetic distinctness of Corsican S. s. meridionalis. Across three complementary analyses of mixed ancestry (i.e., STRUCTURE, PCADMIX, and ELAI), proportions of domestic pig ancestry were estimated at 9.5% in Corsican wild boars, which was significantly higher than in wild boars in Sardinia, where free-range pig keeping was banned in 2012. Comparison of morphologically pure- and hybrid-looking Corsican wild boars suggested a weak correlation between morphological criteria and genome-wide domestic pig ancestry. The study highlights the usefulness of molecular markers to assess the direct impacts of management practices on gene flow between domestic and wild species

Predicting Antidepressant Effects of Ketamine: the Role of the Pregenual Anterior Cingulate Cortex as a Multimodal Neuroimaging Biomarker

Background: Growing evidence underscores the utility of ketamine as an effective and rapid-acting treatment option for major depressive disorder (MDD). However, clinical outcomes vary between patients. Predicting successful response may enable personalized treatment decisions and increase clinical efficacy. Methods: We here explored the potential of pregenual anterior cingulate cortex (pgACC) activity to predict antidepressant effects of ketamine in relation to ketamine-induced changes in glutamatergic metabolism. Prior to a single i.v. infusion of ketamine, 24 patients with MDD underwent functional magnetic resonance imaging during an emotional picture-viewing task and magnetic resonance spectroscopy. Changes in depressive symptoms were evaluated using the Beck Depression Inventory measured 24 hours pre- and post-intervention. A subsample of 17 patients underwent a follow-up magnetic resonance spectroscopy scan. Results: Antidepressant efficacy of ketamine was predicted by pgACC activity during emotional stimulation. In addition, pgACC activity was associated with glutamate increase 24 hours after the ketamine infusion, which was in turn related to better clinical outcome. Conclusions: Our results add to the growing literature implicating a key role of the pgACC in mediating antidepressant effects and highlighting its potential as a multimodal neuroimaging biomarker of early treatment response to ketamine. Keywords: antidepressant effects; ketamine; multimodal neuroimaging biomarker; pgACC; pregenual anterior cingulate cortex

Interdisziplinäre Studienprojekte gestalten: Aus der Praxis für die Praxis

In dem Praxisband werden Konzepte und praktische Umsetzung von fachbereichsübergreifenden Studienprojekten dokumentiert. Grundlage ist das Know-how aus über 30 interdisziplinären Projekten für 10 000 Studierende an der Technischen Universität Darmstadt. Die Publikation wendet sich an Lehrende, Hochschuldidaktiker sowie Lehr- und Studiengangentwickler. Das Autorenteam führt in das didaktische Konzept ein und erläutert die Gestaltung interdisziplinärer Wochen-, Semester- und Kleingruppenprojekte. Schwerpunkte der weiteren Kapitel sind die Qualifizierung von Studienprojekt-Tutoren sowie der strukturelle Rahmen für die flächendeckende Einführung von interdisziplinären Studienprojekten. Zahlreiche Übersichten, Checklisten, Beispiele und Vorlagen erleichtern die Umsetzung in die Praxis.The practical handbook documents concepts and practical implementation of interdepartmental study projects. It is based on know-how from more than 30 interdisciplinary projects for 10,000 students at Technische Universität Darmstadt. The publication is intended for teaching staff, university educationalists, as well as course developers. The team of authors gives an introduction to the didactic concept and explains the design of interdisciplinary weekly and semesterly projects and projects in small groups. Other chapters focus on qualification of study project tutors, as well as structural frameworks for comprehensive introduction of interdisciplinary study projects. Practical implementation is facilitated by numerous overviews, checklists, examples and models

Slowly but surely: gradual diversification and phenotypic evolution in the hyper-diverse tree fern family Cyatheaceae

Background and Aims The tremendously unbalanced distribution of species richness across clades in the tree of life is often interpreted as the result of variation in the rates of diversification, which may themselves respond to trait evolution. Even though this is likely a widespread pattern, not all diverse groups of organisms exhibit heterogeneity in their dynamics of diversification. Testing and characterizing the processes driving the evolution of clades with steady rates of diversification over long periods of time are of importance in order to have a full understanding of the build-up of biodiversity through time. Methods We studied the macroevolutionary history of the species-rich tree fern family Cyatheaceae and inferred a time-calibrated phylogeny of the family including extinct and extant species using the recently developed fossilized birth–death method. We tested whether the high diversity of Cyatheaceae is the result of episodes of rapid diversification associated with phenotypic and ecological differentiation or driven by stable but low rates of diversification. We compared the rates of diversification across clades, modelled the evolution of body size and climatic preferences and tested for trait-dependent diversification. Key Results This ancient group diversified at a low and constant rate during its long evolutionary history. Morphological and climatic niche evolution were found to be overall highly conserved, although we detected several shifts in the rates of evolution of climatic preferences, linked to changes in elevation. The diversification of the family occurred gradually, within limited phenotypic and ecological boundaries, and yet resulted in a remarkable species richness. Conclusions Our study indicates that Cyatheaceae is a diverse clade which slowly accumulated morphological, ecological and taxonomic diversity over a long evolutionary period and provides a compelling example of the tropics as a museum of biodiversity

Structure guided fluorescence labeling reveals a two-step binding mechanism of neomycin to its RNA aptamer

Publisher's version (útgefin grein)The ability of the cytidine analog Ç m f to act as a position specific reporter of RNA-dynamics was spectroscopically evaluated. Ç m f-labeled single-and double-stranded RNAs differ in their fluorescence lifetimes, quantum yields and anisotropies. These observables were also influenced by the nucleobases flanking Ç m f. This conformation and position specificity allowed to investigate the binding dynamics and mechanism of neomycin to its aptamer N1 by independently incorporating Ç m f at four different positions within the aptamer. Remarkably fast binding kinetics of neomycin binding was observed with stopped-flow measurements, which could be satisfactorily explained with a two-step binding. Conformational selection was identified as the dominant mechanism.Deutsche Forschungsgemeinschaft (DFG) through the Collaborative Research Center (CRC) 902; ‘Molecular Principles of RNA-based Regulation’ sub-projects A7, B14 and Mercator Fellowship. Funding for open access charge: DFG (CRC902); sub-projects A7, B14 and Mercator Fellowship.Peer Reviewe