OPUS 4 | Search

660 search hits

1 to 100

Sort by

Exact methods for discrete Γ-robust interdiction problems with an application to the bilevel knapsack problem (2023)

Beck, Yasmine ; Ljubić, Ivana ; Schmidt, Martin

Developing solution methods for discrete bilevel problems is known to be a challenging task—even if all parameters of the problem are exactly known. Many real-world applications of bilevel optimization, however, involve data uncertainty. We study discrete min-max problems with a follower who faces uncertainties regarding the parameters of the lower-level problem. Adopting a Γ-robust approach, we present an extended formulation and a multi-follower formulation to model this type of problem. For both settings, we provide a generic branch-and-cut framework. Specifically, we investigate interdiction problems with a monotone Γ-robust follower and we derive problem-tailored cuts, which extend existing techniques that have been proposed for the deterministic case. For the Γ-robust knapsack interdiction problem, we computationally evaluate and compare the performance of the proposed algorithms for both modeling approaches.

On a Computationally Ill-Behaved Bilevel Problem with a Continuous and Nonconvex Lower Level (2023)

Beck, Yasmine ; Bienstock, Daniel ; Schmidt, Martin ; Thürauf, Johannes

It is well known that bilevel optimization problems are hard to solve both in theory and practice. In this paper, we highlight a further computational difficulty when it comes to solving bilevel problems with continuous but nonconvex lower levels. Even if the lower-level problem is solved to -feasibility regarding its nonlinear constraints for an arbitrarily small but positive , the obtained bilevel solution as well as its objective value may be arbitrarily far away from the actual bilevel solution and its actual objective value. This result even holds for bilevel problems for which the nonconvex lower level is uniquely solvable, for which the strict complementarity condition holds, for which the feasible set is convex, and for which Slater’s constraint qualification is satisfied for all feasible upper-level decisions. Since the consideration of -feasibility cannot be avoided when solving nonconvex problems to global optimality, our result shows that computational bilevel optimization with continuous and nonconvex lower levels needs to be done with great care. Finally, we illustrate that the nonlinearities in the lower level are the key reason for the observed bad behavior by showing that linear bilevel problems behave much better at least on the level of feasible solutions.

Imperfect collusion in monitored markets with free entry (2023)

von Auer, Ludwig ; Pham, Tu Anh

Surveys of antitrust cases reveal that colluding firms usually (1) attempt to minimise the risk of prosecution, (2) achieve merely imperfect levels of collusion, (3) compete against some independently acting firms, and (4) adjust to market entries and exits. In contrast, existing oligopoly models neglect some of the four listed stylised facts and, thus, overlook important interdependencies between them. Therefore, the present paper develops a general quantity leadership model that simultaneously accommodates all four stylised facts. The model is a three-stage game in which each firm must make three consecutive decisions: market entry or not, collusion or not, and output quantity. The framework is augmented by an antitrust authority that ensures free market access. In addition, the antitrust authority may directly obstruct collusion and it may threaten prosecution. The results of this study indicate that the latter two instruments are rather ineffective.

Group singing through the lens of polyvagal theory: A pilot study in patients with Parkinson's disease (2025)

Wünnenberg, Elke ; Baumann, Nicola

There is a need to counteract the chronic progression of Parkinson’s disease (PD). This complex challenge requires new theoretical frameworks and practical strategies. In this study, we implemented group singing in line with the Singing Hospitals format and examined it through the lens of Polyvagal Theory to evaluate its potential benefits for people with PD. According to Polyvagal Theory, facilitating a shift in autonomic states from defense to safety and social engagement may enhance physiological regulation and thereby promote well-being across physical, mental, emotional, and social dimensions. In a pilot study, we recruited patients with PD and examined their responses to two group singing formats (weekly sessions: N1 = 13, one-day-workshop: N2 = 14) and a non-singing control group (N3 = 22). We designed scales of physical, mental, emotional, and social states that PD patients rated before and after eight one-hour singing sessions (N1) or an eight-hour singing workshop (N2). Findings show that PD patients benefited from group singing across both settings (large effect size: d = 2.43). Furthermore, self-reported interoceptive sensibility, used as a proxy for polyvagal autonomic reactivity, showed a substantial reduction in discomfort after weekly singing, while remaining constant in the control group (large effect size: d = 0.94). We observed the predicted singing-dependent effects and interpreted them as a shift in autonomic regulation consistent with Polyvagal Theory. Singing may represent a feasible, low-threshold resource for coping. Furthermore, Polyvagal Theory may provide an innovative framework for PD and help to bridge motor and non-motor symptoms.

I am Once Again Asking for Your Attention: A Replication of Feature-Based Attention Modulations of Binding Effects with Picture Stimuli (2025)

Singh, Tarini ; Schöpper, Lars-Michael ; Frings, Christian

Action control theories assume that stimulus and response features are integrated or bound into short term episodic traces. A repetition of any of these features results in a retrieval of the entire episodic trace, and can thus facilitate or interfere with future actions. Along with stimuli features, features of the response and any other irrelevant stimuli that are present, are also integrated into such traces and can influence future actions. Using word stimuli, Singh et al. (2018) observed that such so-called binding effects are larger for attended features relative to unattended features. This was the case even for features generally believed to be automatically processed, like valence. Since previous research has shown differences in the processing of word and picture stimuli, it is questionable whether the attentional modulations in the above study would extend to picture stimuli. In order to examine this question, Experiment 1 replicated the design of Singh et al. (2018) but used picture instead of word stimuli. In order to directly compare word and picture stimuli, the data of Singh et al (2018) were re-analysed together with the data of the present study. In Experiment 2, the alternative hypothesis, that the effects were driven by the encoding of stimulus contingencies, was tested. Taken together, the findings of the present study replicate those of Singh et al. (2018), indicating that even with picture stimuli, valence related binding effects are modulated by attention allocation.

Effects of Proctoring on Online Intelligence Measurement: A Literature Overview and an Empirical Study (2025)

Scherrer, Vsevolod ; Petry, Nicolai ; Breit, Moritz ; Urban, Julian ; Preuß, Julian ; Preckel, Franzis

Remote intelligence testing has multiple advantages, but cheating is possible without proper supervision. Proctoring aims to address this shortcoming, yet prior research on its effects has primarily investigated reasoning tasks, in which cheating is generally difficult. This study provides an overview of recent research on the effects of proctoring and on studies in intelligence test settings. Moreover, we conducted an empirical study testing the effects of webcam-based proctoring with a multidimensional intelligence test measuring reasoning, short-term memory, processing speed, and divergent thinking. The study was conducted in a low-stakes context, with participants receiving a fixed payment regardless of performance. Participants completed the test under proctored (n = 74, webcam consent), unproctored random (n = 75, webcam consent), or unproctored chosen (n = 77, no webcam consent) conditions. Scalar measurement invariance was observed for reasoning, processing speed, and divergent thinking, but not for memory. Proctoring had no significant main effect on test performance but showed a significant interaction with test type. Proctored participants outperformed the unproctored chosen group significantly in divergent thinking and scored descriptively higher in reasoning and processing speed, but slightly lower in memory. Observable cheating under proctored conditions was rare (4%), mostly involving note-taking or photographing the screen. We conclude that proctoring is crucial for easily cheatable tasks, such as memory tasks, but currently less critical for complex cognitive tasks.

Using Cognitive Diagnostic Models to Evaluate the Two-Process Theory of Matrix Reasoning (2025)

Preuß, Julian ; Preckel, Franzis

Figural matrices are widely used to measure reasoning ability. According to the two-process model of figural matrix reasoning, task performance relies on correspondence finding (linked to induction ability) and goal management (linked to working memory). Cognitive theory suggests that item characteristics (i.e., change rules and design principles of figural elements) are related to the two solution processes and impact item difficulties in a multiplicative, interactive manner. This study tested the multiplicative effect hypothesis by comparing two cognitive diagnostic models using additive and multiplicative effect estimations. A 26-item figural matrix test was administered to 633 high-ability individuals across paper-and-pencil and computer formats. The linear logistic test model (LLTM) and least square distance method (LSDM) were applied to Rasch and 2PL item parameters. Contrary to the multiplicative effect hypothesis, the additive LLTM model showed better item parameter reconstruction than the LSDM that includes multiplicative effects. These results suggest that change rules and design principles may independently contribute to the difficulty of figural matrices. Correspondence-finding demands may primarily arise from design principles, while change rules may primarily contribute to difficulty through goal management demands based on their number and complexity. The findings highlight the need to consider item components related to the phenomenological representation of figural elements when explaining solution processes of figural matrices. Implications for cognitive theory and item construction are discussed.

Psychosocial Risk and Recurrent Hospitalizations (2025)

Maukel, Lisa-Marie ; Schmeller, Sandra ; Weidner, Gerdi ; Beyersmann, Jan ; Spaderna, Heike

Background: Women experience higher rates of adverse events and first rehospitalization after left ventricular assist device (LVAD) implantation compared with men. This study investigated the role of sex and preimplant psychosocial risk in recurrent hospitalizations. Methods: Data from 20,123 INTERMACS patients (21.3% women) were analyzed. Cumulative transition rates (e.g., home to hospitalization) were estimated and Andersen–Gill models, adjusted for covariates, examined the association between sex, preimplant psychosocial risk, and cumulative transition hazards for rehospitalization. State occupation probabilities, the mean number of hospitalizations, and the cumulative average length of hospital stay were calculated and stratified by sex and psychosocial risk. Results: Psychosocial risk preimplant was more prevalent in men than in women (21.4% vs. 17.5%, p < 0.001). The interaction of female sex and psychosocial risk increased rehospitalization hazards, independently of covariates [HRadj 1.11, 95% CI (1.01–1.22), p = 0.036]. One-year postimplant, women with vs. without psychosocial risk had 2.2 vs. 1.8 hospitalizations, while men experienced 1.8 vs. 1.7 hospitalizations, respectively. Women with vs. without psychosocial risk spent 20 vs.16 days hospitalized, and men 15 vs. 14 days (all p < 0.001). Conclusions: Preimplant psychosocial risk independently contributed to recurrent hospitalizations post-LVAD, particularly affecting women. The early identification and management of these factors may reduce rehospitalizations and improve clinical outcomes.

An intricate relationship: stress markers and associative memory in a laboratory experiment in older adults (2025)

Knopf, Luisa ; Domes, Gregor ; Kamp, Siri-Maria

Introduction: Researchers working in the field of cognitive aging frequently encounter highly motivated yet nervous older participants during data collection in the laboratory. Such anecdotal experiences raise the question of whether the affective or physiological response of older participants to psychological laboratory experiments differs to that of young adults, who might be less motivated but also less nervous, as they may be more used to the environment and to learning and memory tests. Methods: In the present study, we collected saliva samples and subjective affective ratings during an EEG experiment on memory, and at home, in young and older adults, while also taking into account sex effects. Results: There was no significant interaction involving time point (laboratory vs. at home) and age group. However, across both time points older males showed significantly higher cortisol-levels than older females, while there was no difference for younger males and females. The trajectories in cortisol levels throughout the session, especially around the memory task, differed by age: While there was a decrease in cortisol levels for younger adults from before to after the memory task, we did not observe such a decrease in older participants. There were few age differences in alpha-amylase or negative affect. However, older adults showed higher ratings of positive affect than younger participants. Importantly, lower cortisol levels before the memory task were associated with higher associative memory performance for older adults. Discussion: Affective reactions to psychological laboratory tasks may hence be an important factor to consider in psychological experiments in the field of cognitive aging.

Finding process-behavioural parameterisations of a hydrological model using a multi-step process-based calibration and evaluation scheme (2025)

Heuer, Moritz M. ; Mohajerani, Hadysa ; Casper, Markus C.

Process-behavioural hydrological modelling aims not only at predicting the discharge of an area within a model, but also at understanding and correctly depicting the underlying hydrological processes. Here, we present a new approach for the calibration and evaluation of water balance models, exemplarily applied to the Riverisbach catchment in Rhineland-Palatinate, Germany. For our approach, we used the behavioural model WaSiM. The first calibration step is the adjustment of the evapotranspiration (ETa) parameters based on MODIS evapotranspiration data. This aims at providing correct evapotranspiration behaviour of the model and at closing the water balance at the gauging station. In the second step, geometry and transmissivity of the aquifer are determined using the characteristic delay curve (CDC). The portion of groundwater recharge was calibrated using the delayed flow index (DFI). In the third step, inappropriate pedotransfer functions (PTFs) could be filtered out by comparing dominant runoff process patterns under a synthetic precipitation event with a soil hydrological reference map. Then, the discharge peaks were adjusted based on so-called signature indices. This ensured a correct depiction of high-flow volume in the model. Finally, the overall model performance was determined using signature indices and efficiency measures. The results show a very good model fit with values of 0.87 for the NSE (Nash–Sutcliffe model efficiency coefficient) and 0.89 for the KGE (Kling–Gupta efficiency) in the calibration period, as well as an NSE of 0.78 and a KGE of 0.87 for the validation period. Simultaneously, our calibration approach ensured a correct depiction of the underlying processes (groundwater behaviour, runoff patterns). We were also able to detect the model parameterisations based on the PTFs that showed satisfactory results across all calibration steps. This enables a targeted selection of the most suitable PTFs for determining the soil properties. This means that our calibration approach allows selecting a process-behaviourally faithful one from many possible parameterisation variants.

The use of a shuffled complex evolution algorithm for calibration of a dynamic leaf emergence model leads to better spatial ETa predictions (2025)

Heuer, Moritz M. ; Hutengs, Christopher ; Casper, Markus C.

Dynamic phenology has so far been a modelling aspect that has received little attention. However, it has been shown that leaf emergence takes place earlier due to the shift in vegetation phase caused by climate change and is strongly dependent on temperature. Here, we demonstrate the calibration of a model for dynamic phenology within the water balance model WaSiM. Temperature sums and dormancy are used as controlling variables. The calibration of the respective parameters was realised using a shuffled complex evolution algorithm. ETa relevant parameters were calibrated based on MODIS data as a reference. Evaluation was done by comparing the ETa curves to MODIS ETa curves as well as a comparison of spatial ETa patterns based on Landsat ETa data. The evaluation shows that the dynamic phenology model used is capable of predicting the start of leaf emergence while also leading to better fitting evapotranspiration curves for the deciduous forest compared with the initial static parameterisation approach.

Emotion management in organizations: the transformation of unreachable feelings to modifiable communication in organizations (2025)

Freis, Tamara

A fundamental challenge confronting modern organizations is to rationalize the affectivity of their members. In contrast to the 19th century, when communication in private settings was largely devoid of emotional content, the current era is characterized by a notable shift toward the incorporation of emotional elements in public discourse. This transformation is unfolding against the background of the ongoing evolution of modern organizations, with the processes of digitization and structural-automation contributing to this shift. The renewed emphasis on emotional semantics is facilitated by these developments—made possible by the fact that they facilitate the experience of the potential future obsolescence of humans as a source of crises. The concept of emotional semantics is currently being discussed in economic discourse, political debate, and in the context of management and leadership. Modern organizations mandate that their members manage their emotions through an organizational culture that fosters reflective communication through empathy. However, an understanding of this process can only be achieved through an examination of historical evidence. The article posits that organizations serve as pivotal actors in the domain of emotion management. Situated at the nexus of historical educational considerations, this perspective offers a nuanced interpretation of the historical evolution of organizational control ambitions. These ambitions have been catalyzed by contemporary trends, such as digitization and the integration of artificial intelligence and have undergone a progressive transformation over time. By sensitizing to the interplay of personal-psychic, institutional and organizational orders, the conceptual instruments for describing a history of emotions become more nuanced. This is demonstrated in the article through the analysis of specific organizational forms, which exemplify a parallel evolution within modern organizational society. Perspectives and discourses in organizational research provide novel approaches to the history of education by considering the organized nature of emotional phenomena. In this regard, the objective of the article is to provide impetus for the field of emotion-sensitive organization and management research which addresses questions pertaining to the transformation of organizations and their historical lines of continuity.

After a Hand Was Lent: Sporadically Experiencing Multisensory Interference During the Rubber Hand Illusion Does Not Shield Against Disembodiment (2025)

Eck, Julia ; Dignath, David ; Kalckert, Andreas ; Pfister, Roland

Observations from multisensory body illusions indicate that the body representation can be adapted to changing task demands, e.g., it can be expanded to integrate external objects based on current sensorimotor experience (embodiment). While the mechanisms that promote embodiment have been studied extensively in earlier work, the opposite phenomenon of, removing an embodied entity from the body representation (i.e., disembodiment) has received little attention yet. The current study addressed this phenomenon and drew inspiration from the partial reinforcement extinction effect in instrumental learning which suggests that behavior is more resistant to extinction when reinforcement is delivered irregularly. In analogy to this, we investigated whether experiencing occasional visuo-motor mismatches during the induction phase of the moving rubber hand illusion (intermittent condition) would result in slower disembodiment as compared to a regular induction phase where motor and visual signals always match (continuous condition). However, we did not find an effect of reinforcement schedule on disembodiment. Keeping a recently embodied entity in the body schema, therefore, requires constant updating through correlated perceptual and motor signals.

Feasibility and user experience of augmented reality psychoeducation and mindfulness body scan for chronic low back pain (2025)

Conen, Robin ; Hepke, Nikolai ; Lohscheller, Jörg ; Mueller, Steffen ; Tibubos, Ana N.

Background: Chronic low back pain (CLBP) is prevalent and a multimodal therapy is indicated, including psychological treatment. Effective conventional treatments involve psychoeducation and mindfulness-based body scans, while virtual reality offers superior but temporary pain relief. Augmented Reality (AR), which combines conventional and virtual methods, is a novel therapeutic strategy. Methods: We investigated the viability and acceptability of an AR intervention for CLBP by incorporating psychoeducation and mindfulness-based body scan techniques. 40 participants in two studies with a one-arm design underwent an educational AR intervention (Study I, n1 = 18) and an enhanced version with an additional body scan (Study II, n2 = 22). The studies focused on evaluating technical feasibility and multiple facets of user experience. Results: The results demonstrated high feasibility with low dropout rates (Study I: 10%, Study II: 0%). User experience ratings ranged from “Above Average” to “Excellent,” with the advanced intervention receiving higher ratings. While Study I showed no significant changes in affect pre- vs. post-intervention, Study II exhibited a significant reduction in negative affect and improved valence. Qualitative analysis provided insights into technical requirements and user perceptions. Discussion: The AR prototype emerges as a promising psychoeducational tool for CLBP, aligning with current treatment guidelines and providing a basis for future controlled clinical trials. Limitations include the absence of a high-pain intervention group, as Study I reported a pain intensity of M = 1.05 and Study II reported M = 1.77 (Range: 0–10). Further research such as clinical trials with control groups is required to validate the efficacy of the piloted approach. The AR-based psychoeducation and mindfulness body scan intervention for CLBP demonstrated technical feasibility and a good user experience.

Development and validation of the Self-Awareness of Ego-Threatening Biases Questionnaire (SAETBQ) (2025)

Brycz, Hanna ; Chybicka, Aneta ; Smoliński, Paweł ; Piotrowski, Andrzej ; Hohmann, Sofia ; Baumann, Nicola

Awareness of social biases is crucial as they impact both individual behavior and societal outcomes. Whereas previous research indicates that self-awareness of ego-nonthreatening biases enhances self-regulation, the effects of self-awareness of ego-threatening biases remain underexplored. Preliminary findings suggest that awareness of ego-threatening biases related to rumination may lead to maladaptive states. However, these findings await replication with standardized instruments. To address this gap, we conducted two studies. In Study 1 (N = 1609), we developed and validated the 12-item Self-Awareness of Ego-Threatening Biases Questionnaire (SAETBQ). Consistent with our hypotheses, self-awareness of ego-threatening biases (as measured by the SAETBQ) correlated with higher moral disengagement, lower self-diagnostic motive, and lower integrative self-knowledge, indicating a tendency towards ego deterioration, whereas self-awareness of ego-nonthreatening biases (as measured by the Metacognitive Self questionnaire) showed the opposite pattern of correlations, indicating a tendency towards beneficial self-regulation. In Study 2 (N = 681), Dark Triad traits correlated positively and Light Triad traits negatively with self-awareness of ego-threatening biases. These results underscore the complex role of self-awareness in managing cognitive biases.

Improving the Understanding of Hydrological Processes in Hydrological Models: From Micro to Macro and Meta Scale (2026)

Heuer, Moritz Maximilian

Hydrological models can be categorised into three groups: empirical models that are based on simple mathematical functions or being data-driven, conceptual models that rely on abstract combinations of storages and fluxes to depict catchment processes, or physically-based models that are structurally complex and incorporate physical interactions at different scales to simulate processes and system states. To calibrate and evaluate especially physically-based models, the use of multi-criteria evaluation schemes has proven to be effective to find model parameterisations that can reproduce multiple catchment processes and states instead of only the discharge. However, uncertainty in models, originating from different sources, often limits the robust interpretability of simulation results, making it necessary to assess how modelling applications can be improved to reduce uncertainty. In this thesis, the relevance of structural adequacy for the depiction of processes in models was demonstrated for the micro level for the example of dynamic phenology, where spatiotemporal model performance was improved by implementing a dynamic approach to modelling leaf emergence instead of a static one. For model evaluation at macro level, it was shown how a multi-criteria approach combining groundwater dynamics, surface runoff patterns and discharge can identify process-behavioural parameterisations and thus improve process depiction in hydrological models. At the meta level, it was demonstrated how the quasi-coupling of a hydrological and a hydraulic model can combine the different strengths of both models to simulate surface runoff processes taking infiltration into account, whereby the relevance of multi-criteria evaluated hydrological models for the derivation of hydrological variables was shown. In addition, uncertainty was explicitly incorporated into model evaluation at the meta level, where a virtual reality model approach was applied to assess the contribution that different variables can make to model evaluation when the associated measurement uncertainty is taken into account. Based on the individual results, it was possible to conclude that uncertainty and its different sources are a relevant factor in model evaluation at different levels and could be reduced by improving structural model adequacy, adapting model application approaches, and explicitly incorporating uncertainty into model evaluations.

Submodular Maximization in Combinatorial Problems (2026)

Münch, Sabine Franziska

The maximization of submodular functions under various kinds of constraints is a central component of many combinatorial optimization problems, since submodular functions naturally cover the property of diminishing returns. This dissertation comprises four scientific articles in which we consider three different combinatorial optimization problems involving the maximization of submodular functions under knapsack or cardinality constraints. The first article considers the maximization of a submodular function defined on a weighted set of items under a knapsack constraint with unknown capacity. Assume that items are packed sequentially into the knapsack, and that an oracle reveals whether an item being attempted for packing fits into the currently packed knapsack. If an item fits, it is packed irrevocably; otherwise, either packing stops immediately (packing without discarding), or the item is removed, and packing continues (packing with discarding). Our main result concerns non-adaptive packing without discarding, under the assumption that the unknown knapsack capacity is greater than or equal to the weight of the heaviest item. Specifically, we present the first polynomial-time algorithm for computing a universal policy that, for any unknown capacity, performs at least as well as the classical greedy algorithm, studied by Wolsey (1982), for the same known capacity. In the second article, we study a game-theoretic variant of maximizing a submodular function under a cardinality constraint. In this variant, an initial solution to the classical problem is determined first. Subsequently, a predetermined number of elements of the ground set, possibly containing elements of the initial solution, are deleted. If any deleted elements were part of the initial solution, they are replaced by a set of at most equal cardinality. The objective is to maximize the value of the ultimate solution, with the deletion being maximally disadvantageous to it. We analyze several special cases of this problem and present polynomial-time algorithms for computing optimal or approximately optimal ultimate solutions. For the general case, we present a polynomial-time algorithm whose approximation guarantee depends on the curvature of the submodular objective function. The last two articles of this dissertation address the classic problem of maximizing a submodular function under a knapsack constraint. The first of these articles focuses on exact solvers: We present a branch-and-bound algorithm along with several acceleration techniques. We compare it against two solvers by Sakaue and Ishihata (2018), which currently achieve the strongest performance reported in the literature, as well as a branch-and-cut algorithm implemented using Gurobi that solves a binary linear reformulation of the submodular knapsack problem, demonstrating that our methods are highly successful. The last article considers variants of the classical greedy algorithm for submodular maximization under a knapsack constraint studied by Wolsey (1982). While the classical algorithm assumes access to an exact incremental oracle in every iteration, we generalize the known approximation results for this algorithm to the presence of only an $\alpha$-approximate oracle that returns in every iteration an item whose relative marginal gain approximates the maximum relative marginal gain by at least $\frac{1}{\alpha}$, with $\alpha \geq 1$ fixed. We also present an approximation result for a variant of the classical greedy algorithm that uses an approximate oracle only in the first iteration and an exact oracle thereafter.

Southern Ocean sea-ice leads: first insights into regional lead patterns, seasonality, and trends, 2003–2023 (2025)

Willmes, Sascha ; Dubey, Umesh ; Heinemann, Günther

Sea-ice leads play a key role in the climate system by facilitating heat and moisture exchanges between the ocean and atmosphere, as well as by providing essential habitats for marine life. This study presents new insights from a gap-filled monthly dataset on sea-ice leads in the Southern Ocean and a first comprehensive analysis of spatial patterns, seasonal variability, and long-term trends of wintertime (April to September) sea-ice leads over a 21-year period (2003–2023). Our findings reveal that leads are ubiquitous in the Southern Ocean and show distinct spatial patterns with maximum lead frequencies close to the coastline, over the shelf break, and close to seafloor ridges and peaks. We see a strong seasonal variability in lead occurrence, with lead frequencies peaking in mid-winter. Weak but significant trends in lead frequencies are shown for the presented period for individual regions and months. Rather small changes in lead occurrence over the 21 years suggest stable wintertime sea-ice compactness despite the observed strong fluctuations and recent anomalies in sea-ice extent. Expanding upon previous work of lead detection in Antarctic sea ice, this study provides first results on the long-term regional, seasonal, and inter-annual variability of sea-ice leads in the Southern Ocean and can thereby contribute to an improved understanding of air–sea-ice–ocean interactions in the climate system. It also underscores the need for further investigation into the individual contributions of atmospheric and oceanic drivers to sea-ice lead formation in the Antarctic.

Continuous Norming of Psychological Tests (2026)

Urban, Julian

Norming of psychological tests is crucial for the accurate interpretation of test scores. Conventional norming, which relies on subgroups, may introduce bias and requires large samples (uneconomic) to achieve high precision (i.e., low standard errors) of the estimated norm scores. Continuous norming has been proposed as a solution to reduce bias and resolve the dilemma between economy and precision. Continuous norming estimates norm scores based on the entire normative samples – rather than subgroups – using (non-linear) regression. The aim of this dissertation is to examine continuous norming methods to improve both test development and psychological diagnostics. To this end, this dissertation comprises four research studies. This first study includes both a systematic review of continuous norming and an empirical study. The systematic review introduces different continuous norming methods and highlights their respective advantages and limitations. The empirical study compares the precision of conventional and continuous norms and investigates the presentation of continuous norms in classical norm tables. The second study provides a systematic overview of German-language tests, showing that continuous norming methods are rarely applied and that descriptions of the norming process in test manuals are often scarce. Such a scarce reporting hinders a critical evaluation of the estimated norm scores. To address this issue, the third study introduces guidelines for reporting on norm-referenced scores. The guidelines cover relevant aspects along the entire norming process and provide detailed information on each aspect. One aspect, where the guidance is limited, is determining the required sample size. The fourth study addresses this gap by providing empirical based guidance to determine the required sample size for continuous norming. For a comprehensive evaluation of continuous norming, I combined the findings of these studies with (1) an illustration of the effects of bias and precision on individual diagnostics and the financial costs of normative studies, (2) an updated systematic literature search, and (3) an examination of applied norming practices in recently published tests. This integration allowed the extraction of seven best practices for continuous norming. The first best practice is to favor continuous over conventional norming, as it effectively resolves the economy-precision dilemma: continuous norming produces less biased norms than conventional norming and requires smaller sample sizes to achieve high precision. Despite these advantages, continuous norming is still rarely applied in German-language tests. The guidelines and sample-size recommendations provided in this dissertation may facilitate a wider adoption of continuous norming methods, thereby improving both test development and psychological diagnostics.

The role of environment and evolution on the tadpole bauplan (2026)

Laudor, Jörn ; dos Santos Dias ; Vera Candioti ; Hermes ; Köhler ; Schulze ; Viertel ; Veith ; Lötters ; Plewnia ; Hönig ; Jung ; Ziegler ; Elle ; Böning

This thesis seeks to improve the understanding of evolution and habitat as key factors forming tadpole morphology (i.e. of larvae of the order Anura), uncovers existing gaps in current research and recommends strategies and directions for future research. The present study improves the knowledge about the influences of evolution and habitat on the bauplan of tadpoles in a global scale ensuring maximum standardization and comparability of the data. In relation to the total number of tadpoles assumed to exist, only a small proportion has been described and only a few of them have been identified genetically. The lack of a global standard for their description makes it difficult to compare data. Using the tadpole of a harlequin frog (Atelopus) from Guiana region, it is shown that only an integrative approach with morphological and genetic data can solve taxonomic problems. In the study area of Madagascar, it becomes evident that in this region the common genetic history only has little influence on morphology, in contrast to the aquatic way of life. Tadpoles from flowing waters develop larger eyes, more robust tail muscles and smaller fins to cope better with current conditions and move more efficiently. In an additional study, the examination is extended to an almost global level. To achieve the intended standardization, over 1000 individuals (tadpoles) from 144 species have been examined. It can be shown that the common evolutionary history on a global scale influences morphology as strongly as the habitat. In addition, the influence of specialized nutrition and the climate is investigated.

Economic Forecast Disagreement and Equity Pricing (2026)

Akbari, Mehran

Expectations play a central role in financial markets, yet investors often disagree about the economy’s future. Such disagreement has long been regarded as a potential driver of asset prices, but it remains uncertain whether it reflects mispricing or a priced source of risk. This study addresses the issue by constructing monthly disagreement indices from Consensus Economics forecasts across 24 OECD markets. Firm-level exposure to economic disagreement is estimated using return regressions. The results reveal pronounced cross-country heterogeneity. In developed markets, particularly the United States, greater exposure to disagreement consistently predicts lower future returns, supporting the mispricing hypothesis. In smaller markets, the evidence is mixed, with some cases indicating positive risk premia and others showing no significant effect. Overall, the findings provide new international evidence that the pricing of forecast disagreement is context-dependent, shaped by market structure and institutional depth.

Trade and Investment Connectivity in Europe and the Chinese Influence (2026)

Dorakh, Alena

This thesis examines how Europe sustains its leadership and competitiveness as a global center for foreign direct investment (FDI) and trade between 1991 and 2023. While EU membership historically functioned as the dominant determinant of inward FDI and trade integration, its relative influence has declined as new structural factors, based on trade dynamics and export-platform strategies, have emerged, together with the growing presence of Asian, especially Chinese, investors establishing production hubs in Central and Eastern Europe to serve the wider EU market. Lower trade costs within Europe have reinforced this shift, leading EU investors to focus on vertical FDI, while non-EU investors to adopt export-platform FDI patterns. Chinese investment has moved from infrastructure-focused projects to strategic-sector FDI, highlighting Europe’s exposure to evolving global industrial and geopolitical dynamics. Chapter 2 examines how traditional determinants of FDI, including EU membership, interact with emerging drivers, such as trade interdependence, export-platform strategies, and Asian influence, to shape investment patterns in Europe. It employs a gravity-based empirical framework augmented with newly developed indicators, comprising the Bilateral Trade Interdependence Index, the Export-Platform Indicator, and Belt and Road Initiative (BRI) participation, together with a functional integration approach, covering over 95% of European countries and their global partners from 2010 to 2023. The findings indicate that trade dependency with non-EU partners grew most rapidly, increasing by 55% between 2011 and 2023. Stronger bilateral trade interdependence is found to significantly predict higher FDI inflows. The BRI analysis and functional classification indicate a shift from infrastructure-focused Chinese investment to strategic sectors, including electric vehicles and semiconductors. Since 2018, export-platform strategies have expanded from Europe’s core economies into Central and Eastern Europe, forming emerging production hubs, and have subsequently moved toward the Western Balkans and Turkey, likely reflecting evolving EU regulations and broader supply-chain realignments. Chapter 3 expands the FDI analysis to cover a longer timeframe, from 1991 to 2017, focusing on the period when EU membership exerted a strong influence on FDI in Europe, transforming member countries from primarily cost-attractive destinations into global investment centers. Using an augmented gravity model covering 39 host and origin countries, the analysis finds that EU membership increased FDI inflows by 23%, with investments from core EU members expanding into new EU member states, while FDI from non-EU countries decreased. At the same time, EU membership may also be driven by trade, and EEA participation reflects non-FDI motivations. The chapter also highlights that EU accession strengthens both market-seeking (horizontal) and efficiency-seeking (vertical) FDI motives and applies methods to address negative and zero FDI values issues, ensuring robust estimation. The inclusion of lagged and lead variables shows that the EU integration process is phased over time, affecting FDI inflows with lags of up to 10–15 years after accession. Chapter 4 expands the range of FDI determinants by deriving trade cost indices as a proxy for connectivity and extending the geographic scope of the analysis. In addition to EU members, the sample includes the Western Balkans, Turkey, and new EU candidates and applicants (Moldova, Ukraine, and Georgia) over the period 2000 to 2020, covering approximately 80% of European FDI flows. Trade costs are calculated for each country in the sample with its trade partners, not only within and between European subregions but also with non-EU partners such as China, and are combined with measures of FDI restrictiveness. The results show that China remains among the EU’s top three trading partners in goods and that trade costs significantly influence FDI inflows in Europe. The analysis also highlights that declining trade costs between European countries have reduced market-seeking (horizontal) FDI, while non-European investors, especially China, increasingly pursue export-platform FDI to serve third-country markets. A sharp reduction in trade costs between the Western Balkans and the EU (-45%) and a smaller decline with China (-35%) illustrates how regional integration reduces the need for local horizontal FDI while reinforcing Europe’s role as a hub for global production. Chapter 5 shows that despite concerns about increasing outside influence, developed European countries remain the dominant source of FDI in the region. The chapter focuses on China’s role, examining FDI patterns across advanced EU members, new member states, and Western Balkan economies between 2000 and 2019, while distinguishing the effects of EU integration and BRI participation on FDI. Chinese influence has expanded primarily through the Belt and Road Initiative, particularly in accession and neighboring countries. Although BRI participation does not significantly increase FDI on its own, reflecting the dominant part of loan-financed infrastructure rather than private investment, it has strengthened physical and digital connectivity, laying the groundwork for future, longer-term FDI. The analysis also shows that intra-EU trade costs declined significantly after the 2004 and 2007 enlargements, while trade costs between the Western Balkans and China have fallen steadily since the launch of the BRI in 2013. As a result, Chinese influence is more pronounced in new EU member states and Western Balkan economies than in Western Europe. Over time, enhanced connectivity and supply-chain integration may support more diversified FDI inflows.

Towards Seamless Integration: Exploring Cross-Reality for Extending Physical Office Workspaces (2026)

Feld, Nico

Immersive systems, like Augmented and Virtual Reality, offer new paradigms fordigital interaction, but confining users to a single reality often presents drawbacksfor complex tasks. Cross-Reality systems, which integrate multiple realities into asingle experience, have significant potential to enhance existing professional workflows by combining the unique strengths of physical and virtual environments. Thisdissertation investigates how Cross-Reality can enhance professional workflows byusing the traditional office as a primary use case, focusing on the central question:How can CR enhance existing workflows in physical settings by extendingthe physical environment with virtual content and environments?To address this, the dissertation presents a body of empirical work structuredaround isolating and investigating one core design challenge for each of the threeprimary types of Cross-Reality systems. The work first addresses transitionalCross-Reality systems, which allow users to switch between different realities, byexamining how to design effective transitions. It demonstrates that in task-drivenscenarios, users prioritize efficient transitions that minimize cognitive disruptionover more elaborate or interactive ones. Next, the dissertation tackles the fundamental problem of unwanted occlusion in Augmented Virtuality, a form of substitutional Cross-Reality systems, which integrate objects from one reality intoanother. It introduces and evaluates technical strategies to ensure physical toolsremain accessible within virtual spaces, revealing a critical trade-off between theefficacy of these solutions and user experience factors like cybersickness. Finally,the research explores multi-user Cross-Reality systems that enable collaborationbetween multiple users who may be experiencing different degrees of virtualitysimultaneously, and the complexities of enabling collaboration across multiplestages, underscoring the unique challenges of supporting shared awareness andmanaging asymmetric roles.These findings are grounded by a detailed analysis of the underlying hardware, which highlights how technical and perceptual issues inherent to VideoSee-Through and Optical See-Through Head-Mounted Displays directly impactthe feasibility and design of Cross-Reality systems. The overarching contributionof this dissertation is to provide a set of empirically-grounded design principlesfor applying Cross-Reality in productivity-focused environments. By shifting thedesign focus from entertainment to pragmatic qualities, this work offers valuableinsights into creating Cross-Reality systems that genuinely enhance workflows, prioritizing efficiency, usability, and seamless interaction while navigating technical

From Gene to Ecosystem – Retrospective molecular biodiversity monitoring of plant-associated arthropod communities and abiotic stress on plants (2026)

Stothut, Manuel

From Gene to Ecosystem – Retrospective molecular biodiversity monitoring of plant-associated arthropod communities and abiotic stress on plants

Hybrid and Quality Aware Federations of Linked Data Fragment Interfaces and Traditional RESTfulWeb APIs (2026)

Zeimetz, Tobias

This thesis presents four contributions in the domains of schema/ontology alignment and query processing. First, we present a novel alignment approach, denoted as FiLiPo (Finding Linkage Points), to align the schema of RDF knowledge bases with the response schema of RESTful Web APIs. FiLiPo only requires knowledge about a knowledge base (e.g., class names) but no prior knowledge about the Web APIs’ data structure. It uses fifteen different string similarity metrics to find an alignment between the schema of a knowledge base and that of aWeb API. Next, a benchmark system named ETARA (Evaluation Toolkit for API and RDF Alignment) is introduced that was created with the goal to simulate RESTful Web APIs and is able to cover all important characteristics of Web APIs, i.e., latency, timeouts, rate limits and, furthermore, provides configurable response structures (e.g., JSON or XML). Additionally, it was designed to support researchers during the development of alignment systems. Afterward, the alignments determined by FiLiPo are used to create a hybrid and federated query processor named TunA (Tunable Query Optimizer forWeb APIs and User Preferences), which allows SPARQL queries combining knowledge bases and RESTful Web APIs and is tunable towards user preferences, i.e., coverage, reliability and execution time. The primary goal of TunA is to return a query result that satisfies the user’s preferences in terms of data quality, even when using unreliable data sources by performing a majority vote over multiple sources. Lastly, we present a federated query processor, denoted as ORAQL (Overlap and Reliability Aware Query Processing Layer), which uses overlap information to reduce the number of selected sources that are available in a federation. The goal is to reduce redundant data and, hence, improve the query execution speed. Therefore, ORAQL uses a profile feature that provides information about the overlap between all data sources of a federation. Furthermore, we extend the quality estimation of TunA to cover Triple Pattern Fragment interfaces to ensure a user-provided reliability goal.

Tensile Strength Simulation-based Nonwoven Material Design by Surrogate Model Optimization (2023)

Harmening, Marc

This thesis serves as proof of concept for the tensile strength simulation-based nonwoven material design. Objective is the adjustment of the parameters of an underlying production process with regard to a desired tensile strength behavior (optimization). As an example, we focus on the nonwoven airlay production and consider a thermobonding procedure for the consolidation of the nonwoven fabrics. To be able to map production parameters to the associated tensile strength behavior, we present a model-simulation framework composed of a model for the nonwoven fiber structure generation and a model for the nonwovens’ mechanical behavior under vertical load. The model for the fiber structure generation replicates the stochastic fiber lay-down of the airlay production and results in a random three-dimensional fiber web. This web is consolidated using a virtual bonding procedure that mimics the thermobonding of the nonwoven material. The topology of the resulting adhered fiber structure can be described by a graph, which serves as basis for the subsequent tensile strength simulation. The model used for this purpose describes the mechanical behavior of the material at fiber network level. Therefore, the considered fiber structure sample is interpreted as truss and the fiber connections are equipped with a nonlinear material law, which allows to describe the elastic phase of the nonwovens’ tensile strength behavior. The existence and uniqueness of a solution to the model as well as its numerical treatment are discussed. Moreover, we present data reduction strategies that enable more efficient simulations by removing fiber structure parts that do not contribute to the tensile strength behavior. As it becomes evident from the numerical experiments, a single tensile strength simulation for a production-like virtual sample is already computational demanding. Costs accumulate further, since Monte-Carlo simulations are required to account for the randomness in the fiber structure generation. Thus, direct simulations provide an infeasible basis for the nonwoven material design. This motivates the use of a predictive surrogate for optimization. Therefore, we consider regression-based approaches at different levels of information within the simulation framework. It turns out that the coupling of a polynomial model, for the fiber structure feature inference, with a linear one, for the stress-strain curve inference, yields accurate predictions. Once trained, the regression models allow for efficient evaluations and thus represent a suitable surrogate for the nonwoven material design. In this context, we discuss two exemplary problems of interest for the application: First, a tracking-type problem that aims to find the production parameters that result in a desired tensile strength behavior, expressed in terms of stress-strain curves. Second, an in-corridor maximization problem, which aims to identify the production parameters that maximize the probability of ending up in a specified stress-strain corridor.

Essays in Price Measurement with Statistical and Machine Learning Methods (2025)

Radjabov, Botir

Price indices play a vital role in economic measurement as they reflect price levels and measure price fluctuations. Price level measures are used with macroeconomic indicators to express them in real terms. These measures are also used to index wages, rents, and pensions. Furthermore, they are used as a reference for monetary policy conducted by central banks. Therefore, the provision of accurate price indices is one of the most important goals of National Statistical Institutes (NSIs), and numerous studies have been devoted to this goal. This cumulative dissertation also contributes to this goal. It contains four chapters, each of which represents a separate research. The first two studies are devoted to the treatment of seasonal products by using different price index methods. The first research is co-authored with Ken van Loon. The third research is dedicated to finding the most accurate method to make price predictions for missing products. The fourth research is focused on the treatment of products by using different price index methods when products’ quality characteristics are available.

CYBERPUNK – GAME – POETRY: Rostislav Amelin’s “SimStab” (2024)

Leiderman, Daniil ; Lipovetsky, Mark

The article discusses “SimStab” [Simulator of Stability], a poetic performance by a young Russian poet, Rostislav Amelin, as an effective hybrid of the innovative poetry, video game, and the cyberpunk genre models. The interaction of these components produces strong, yet not necessarily obvious political over-tones, testing the limits of the audience’s (or readers’, or players’) agency. Like many other cyberpunk texts, “SimStab” explores the conflict between the desire to resist colonization by the pervasive powers dominating contemporary society, and the absolute necessity of willingly colonizing your own body and subjectivity with the products of these powers. Both the poem, game and their shared text embody spaces of utopia reliant on repressed sites of formless abjection, which paradoxically become a source of anarchic freedom. Thus, in “SimStab” the ludic algorithmic with its procedural rhetoric (Ian Bogost) creates spaces of formlessness which repeats the liberatory promise of cyberpunk literature.

Performative Translation: Latvia’s Orbita Group as a Post-Monolingual Heterotopia (2024)

Platt, Kevin M. F.

The Orbita multimedia and poetry collective, based in Riga, Latvia, has succeeded in making poetry written in Russian an integral part of the Latvian cultural and literary scene, despite the burden borne by Russian language and culture in this society as a result of still unsettled and contested histories of Russian and Soviet imperial domination and cultural imperialism. The article explains this achievement as resulting from the Orbita collective’s practices of “performative translation,” which make translation a highly visible and central element of various forms of artistic activity, including multimedia installations, book publishing, video poetry, public performance, proper, and more. In traditional cultural configurations, translation is thought to transfer the essential features or the spirit of a text from one literary language to another in a manner that makes possible the translation’s readers’ sense of unmediated contact with the original. Such a conception of translation supports the monolingual paradigm – the cultural ideology of separate and distinct national languages – and the political actualities to which it corresponds. Orbita’s practices of performative translation, in contrast, create a multilingual heterotopia in which the actuality of translation as mediation is rendered visible, the boundedness and distinctiveness of national literary languages is undermined, and the social necessity and ubiquity of acts of translation is brought to the fore.

Breaking up the Canon of Literary Modernity: Classicism in the Ecopoetics of David Hinton and the Materialism of Zeng Shaoli. A Preliminary Outline of Epistemological Changes in Contemporary American and Chinese Lyricism (2024)

Kraushaar, Frank

The target of this essay is to open possible pathways to approach the phenomenon of a self-remodeling of classicist poetry in the 20th and early 21st century by focusing on the process from two different angles rarely perceived as related to each other: first, the remodeling of Chinese lyrical classicism through a strand of modern American poetry harking back to Ezra Pound and currently crystallized in the translations of David Hinton and, second, the transition that modern Chinese poetry written in classical language and conforming to prosodic rules of classical style poetry, sometimes referred to as “old style poetry” jiu ti shi, underwent after its rebirth as “unofficial” poetry online since the beginning of this century. Although there are obviously no direct links between the aforementioned tradition of modern American poetry and neoclassicist cyberpoets like Zeng Shaoli I argue that in both cases the classicist inspiration and poetic drive is motivated by concern with the increasing imbalance between natural, social, and individual resources, on the one hand, and an indomitable desire to accumulate economic and political power on the other. A permanent devaluation of language in the human realm, matched by a permanent devaluation of currencies in the economic sphere, provokes poetic responses in the very interest of humanity. The neoclassicist lyricisms that I draw into comparison display both subtle distinctions and common traits in this response to the starkly different environments of their respective contemporary literary scenes.

From Incoherence to Sustainability: Performance, Activism, and Social Media in the Most Recent Russian Poetry (2024)

Korchagin, Kirill

This article considers the evolution of poetic performance on the basis of several Russian poets of the 2010s. The type of performance in question, which originally implied active absorption in the poetic text, occupied an important place in Russian art of the twentieth century – from the first experiments of the historical avant-garde to Moscow Conceptualism (above all, in the their “Collective Actions”). As such, it has always maintained a closeness to the poetic work and was most often practiced by poets who sought to extend their texts beyond the space of the page and into the “external” world. In the 2010s, however, with the development of social media, the opposite trend is noticeable – poets, while declaring their connection to the performative traditions of Moscow Conceptualism, transfer their performative activity into a textual space organized by social media platforms. The central hypothesis of this article is that all of these poets react differently to the methods of discursive organization provided (and enforced) by social networks and strive in different ways to liberate themselves from the censorship of the algorithm: some emphasize the discursive incoherence of the platform, while others, on the contrary, seek to develop a sustainable manner of uniting private discourses into a new totality.

Preliminary Note (2024)

Stahl, Henrieke

This volume brings together contributions addressing the intersections of political poetry, performativity, and the internet. The essays are based on presentations given at workshops and conferences organized by the DFG Centre for Advanced Studies “Russian-Language Poetry in Transition: Poetic Forms of Dealing with Boundaries of Genre, Language, Culture and Society between Europe, Asia and America” (2017-2023). The conferences took place in 2018-2019, at a time when neither the coronavirus pandemic nor Russia’s brutal invasion of Ukraine were foreseeable, and the contributions have not been updated in light of these catastrophes. The articles presented here deal with recent poetry and focus on the connection between politics, performativity, and the internet in multiple literatures and intercultural relations. Although the majority of these texts belong to the Russophone world, poetry from Serbia, Latvia, and China is also considered. The contributors demonstrate, on the one hand, how newer poetry softens genre distinctions and formally tends towards multimedia hybridization and, on the other, how it transcends or dissolves linguistic, cultural, and social boundaries. Dr. Ekaterina Friedrichs and Ms. Lena Rosalin Schwarz were involved in preparing this publication for printing. We would like to thank them both for their careful review and wonderful cooperation.

Comparing Inger Christensen and Birgitta Trotzig (2024)

Ringgaard, Dan

The essay compares Inger Christensen’s (1935-2009) poetry and poetics with the work of the Swedish writer Birgitta Trotzig (1929-2011). It tests the potential of comparison by asking what happens if we compare what might be the two most prominent women writers of Nordic post-war modernism, two writers whose paths have crossed over the years. The first half of the paper traces a shared constellation of motifs (eye/butterfly/death) within two books of poetry, Trotzig’s “Anima” (1982) and Christensen’s “Sommerfugledalen” (1991). The initial comparison of motifs leads to a shared poetics. It offers a trotzig’ian version of Inger Christensen’s version of the condition of secrecy and fundamental parallels in their philosophy of language and the subject. But it also points to a major difference between the real as a mystic category in Trotzig and Inger Christensen’s more seamless, lucid, and dreamlike style. Advancing further into a stylistic comparison the linguistic and visionary abundancy of Trotzig’s “Anima”-poems reveals an overlooked quality in Christensen’s: That Christensen’s poems are also luxurious, albeit, typically, with moderation. The balancing of sense and sensibility appears by comparison to be a key trait in her poetry, highlighting its classical inclination. The paper demonstrates how comparison makes its subject visible by way of the other, and how comparison points out new nuances or flavors in the texts as it opens a conversation between two major women writers of Nordic modernism.

Textile Textuality in Inger Christensen: “Letter in April” and Amalie Smith: “Thread Ripper” (2024)

Rösing, Lilian Munk

Departing from Roland Barthes’ association of text and textile, and feminist theory on weaving as text production, this article analyzes the textile qualities of Inger Christensen’s “Letter in April” (1979) and Amalie Smith’s “Thread Ripper” (2020). In “Letter in April”, Christensen establishes a connection between writing and spinning or weaving through their shared temporality of varied repetition. In “Thread Ripper” Smith alludes to Christensen and makes of the continuity between text and textile not only the main theme of the book, but also its structuring principle. Through a materialist conception of the text, regarding it as a woven fabric, the article focuses on the textual patterns of the two works (stylistic figures in Christensen, graphic composition in Smith). The connection from Christensen to Smith leads to a further connection to ecocritical conceptions of weaving as no less than a cosmological principle. On a concluding note, the article argues that weaving is not only connecting, but also disconnecting, cutting.

Heliocentric Utopianism: Ecological Imagination and Utopian Longing in Inger Christensen and in Contemporary Danish Literature (2024)

Nexø, Tue Andersen

This essay discusses the relationship between Inger Christensen’s work and contemporary Danish eco-literature. Christensen can seem like a towering predecessor. Yet, the relationship is more complex than a question of anxiety of influence. This essay argues that Christensen and contemporary Danish literature exhibit differing ecological imaginaries, and that this becomes clear when one examines Christensen’s utopian writing, her heliocentric utopianism, of the late seventies and early eighties, and when one examines how ecological threats are depicted in her work. For Christensen, the paradigmatic threat to the world is the nuclear bomb and its excessive use of energy, for today’s literature it is the feedback loops of pollution, exemplified in the threat of climate change.

Inger Christensen in Edenkoben (2024)

Bergmann, Franziska

This article discusses the high regard for Danish poet Inger Christensen in Germany and her connection to the Künstlerhaus [Artists’ Residence] in Edenkoben, located in Rhineland-Palatinate. The Künstlerhaus serves as a cultural institution where international artists from various fields can reside and collaborate. Inger Christensen had strong connections with the Künstlerhaus Edenkoben and participated in its German-Danish poetry project. During her visits to Edenkoben, she wrote several poems. In an essay, the poet described Edenkoben’s landscape as paradise-like. This article, on the one hand, examines these texts in the context of Inger Christensen’s stay in Edenkoben. On the other, it sheds light on “Weg der Gedichte”, a project that stages Inger Christensen’s poem “Erinnerung an Edenkoben” in a public space around the Künstlerhaus, showcasing the role of poetry in rural settings and its ability to enhance the experience of nature and hiking.

What Makes a Poem Aggressive? A Comparison of Joseph Brodsky’s and Aleksandr Byvshev’s Versions of «На независимость Украины» [On the Independence of Ukraine] (2023)

Schlund, Katrin

Shortly after Ukraine had declared its independence in December 1991, Joseph Brodsky, Nobel Prize Winner in Literature 1987, wrote the poem «На независимость Украины» [On the Independence of Ukraine], which sarcastically mourns the separation of Russia and Ukraine. In 2015, responding to the armed conflict in Ukraine, teacher and poet Aleksandr Byvshev issued a reply to this poem under the same title, taking the side of Ukraine. Both poems have been perceived as aggressive, insulting, and anti-Ukrainian or anti-Russian, respectively. This paper asks the question of whether – and in what sense – the two poems are aggressive by drawing on the linguistic features of the two texts. The investigation of the linguistic characteristics of the poems is supplemented by an analysis inspired by argumentation theory, since, as will be shown, both texts are essentially argumentative.

Relocating “China” in Contemporary American Poetry: The Case of Timothy Yu (2023)

Kunze, Rui

This article examines “China” in contemporary American poetry using the example of Timothy Yu’s poems, titled “Chinese Silence,” which rewrite and / or parody texts from the American literary canon as well as public communication. It proposes a hall-of-mirrors reading of these poems in order to show how Yu’s poems refer to, reflect on, and relocate other authors’ writing of “China.” It argues that Yu’s poems, instead of making claims for an authentic “China,” attempt to bring Chinese Americans’ lived experience into the American literary tradition.

Contemporary Japanese Poetry and Politics: An Overview (2023)

Morton, Leith

This study will examine two different types of poetry that can be broadly classified as “political” in an attempt to reach an understanding of the interaction between politics and poetry in modern Japan. The first sampling of poetry will be taken from the Internet and will be amateur verse belonging to such traditional genres of poetry as haiku / senryū and tanka that can be classified as agitprop poetry. The second more substantive sampling will be taken from “professional” poets and will mainly fall into the shi (free verse) category. I will also discuss various literary critics and also thinkers on aesthetics from both Japan and the West to further elucidate the relationship between poetry and politics, to elaborate a broad definition of the political domain appropriate to Japanese verse, and also to investigate the issue of how to read and evaluate poetry as literary art. The study will be divided into five parts: first, the introduction outlining and probing the issues under discussion, next, an examination of Japanese agitprop poetry drawn from the Internet, then a brief interregnum on (literary) theory focusing on two theoreticians, Yoshimoto Takaaki (1924–2012) from Japan and Jonathan Culler (b. 1944) from the West, followed by an investigation of contemporary free verse political poetry, specifically the verse of Minashita Kiryū (b. 1970), Misumi Mizuki (b. 1981), Yotsumoto Yasuhiro (b. 1959), and Arai Takako (b. 1996).

Tactile Communism: Keti Chukhrov’s Post-Soviet Dramatic Works and the Legacy of Soviet Defectology (2023)

Osipova, Anastasiya

In this article, I analyze the character of hyper-naturalism and exaggerated tactility in dramatic poems by contemporary Russian-Georgian philosopher and writer Keti Chukhrov. I argue that, while descriptions of violence, physiological functions, and abject poverty are common for post-Soviet art, in Chukhrov’s work these elements perform radically different task than in the pessimistic and de-ideologized chernukha, or the style of grim realism. Her approach to matter is also distinct from the historic Russian avant-garde tradition, which relished intensified sensations but did not offer constructive ways of inscribing their immediacy into coherent cultural continuity. Instead, her dramatic poems bear pedagogical, even rehabilitative stakes for recuperating the individual sensations of alienated people into meaningful and shared cultural experiences. In this article, I discuss her approach to drama as mobilizing the tradition of Soviet Marxist defectology, a special educational method of socializing disabled, cognitively impaired, or otherwise disadvantaged people. Pioneered in the Soviet Union in the 1920s by Lev Vygotsky and suppressed in the 1930s, defectology found further application in the 1960s and 1970s in the work of the Zagorsk boarding school for the deafblind, led by Vygotsky’s student Alexander Mescheriakov and Evald Ilyenkov, a Marxist-Hegelian philosopher who is a central figure for Chukhrov’s philosophical research. One of the key tasks of Meshcheriakov and Ilyenkov was to help their deafblind students to overcome isolation through learning to translate their purely tactile sensations into deliberate communicative acts. While Zagorsk offered Ilyenkov an opportunity to test and apply his theory of the collectivist formation of personality, for Chukhrov it is theater that has become the sphere for experimental, practical extension of her scholarly research into Soviet Marxist thought and socialist culture of the 1960s and 1970s. Her dramatic texts offer models of alternative subjectivization for post-Soviet people to allow themselves once again to recognize the presence of universal values and greater cultural commons behind individual, alienated sensations and experiences.

Case Study: Galina Rymbu, “Moia vagina,” June 2020 (2022)

von Zitzewitz, Josephine

On 27 June 2020, the prominent feminist poet Galina Rymbu published the poem «Моя вагина» (“My Vagina”) on her Facebook feed. «Моя вагина» is a solidarity poem, written in support of artist and LGBTQ activist Iuliia Tsvetkova, who is facing a charge of distributing pornography for her abstract paintings of vaginas in a group on the social media platform VKontakte. Rymbu’s poem created huge resonance: it was shared, translated and republished on various platforms on the web and in print, examined by researchers, and debated as both a work of literature and a political statement. The present article charts the story of this remarkable poem, from its origins to its formal properties, its place within contemporary feminist poetry and its close links to feminist activism, and the reactions it has triggered. It also analyses the follow-up poem Rymbu wrote in reply to her detractors, «Великая русская литература» (“Great Russian Literature”), with a focus on Rymbu’s ingenious play on personal pronouns. Finally, it will briefly look at the role of social media for the literary process in Russia, specifically the field of poetry.

The Body Returns: Recent Poems by Russian Women (2022)

Sandler, Stephanie

Russian feminist poetry has flourished in the post-Soviet period, especially the last decade. It has provided inspiring modes of resistance to all forms of indifference to bodily harms, particularly the harms to women. That poetry is studied here through the lens of feminist theory. The essay argues that a wide range of such theories finds resonance in these poems, and it introduces several key poets: Galina Rymbu, Oksana Vasiakina, Lida Yusupova, Elena Fanailova, and Mariia Stepanova, with a coda on Konstantin Shavlovskii.

The breathless discourse. Narrating death in Louis-Ferdinand Céline’s “Death on Credit,” Samuel Beckett’s “The Unnamable” and Paul Auster’s “4321” (2022)

Veisland, Jørgen

The article analyzes three modernist novels, Louis-Ferdinand Céline’s “Death on Credit,” Samuel Beckett’s “The Unnamable,” and Paul Auster’s “4321”. The texts examined manifest radical discursive changes that are connected with epistemological and ontological conceptions of mind and being. Modern conceptions of being are seen as being based on the non-concepts of exaiphnes, the timeless instant, as developed by Parmenides, sunyata as defined in Buddhist thought, and the indeterminacy of particles as discovered by quantum physics. The idea of being as a state of infinite potentiality impacts the discourse and the form of the modern novel as it moves in the direction of formlessness, thus mirroring the non-substantiality of the human subject. The narrators of the three novels speak at a breathless pace that punctuates and disrupts the narrative and that inserts death as the agent of the negation of meaning.

On the “Flowing Movement” and the “Lofty and Ancient” in Gary Snyder’s Poetry (2022)

Jun-ping, Zhang ; Wei-hang, Chen

On the “Flowing Movement” and the “Lofty and Ancient” in Gary Snyder’s Poetry Gary Snyder, a renowned 20th century American poet, has been strongly influenced by Eastern cultures, especially Chinese. The philosophical spirit of Eastern culture and its intuitive way of thinking have taken root in Snyder’s mind and directly shaped his perception of nature. Hence, in view of the inadequacy of Western literary criticism in interpreting the Eastern dimensions of Snyder’s poetry, this article takes the classical Chinese literary theory “Twenty-Four Styles of Poetry” as its theoretical perspective and uses its categories of “Flowing Movement” and “Lofty and Ancient” to explore how the dissolved or solitary poetic self achieves the mental state of “emptiness” (kong in Chinese Taoism and sunyata in the Buddhist sense) and creates the poetic worlds of the “flowing movement” and the “lofty and ancient” (transcendence) in Snyder’s poems.

The Presocratics in Russian Modernism and the Avant-Garde: Parmenides – Herakleitos – Zeno (2022)

Hansen-Löve, Aage

There are astonishingly numerous and profound influences of the Pre-Socratics – especially Herakleitos and Zenon – on Russian literature between realism and the avant-garde of the 1920s. The focus here is on the concepts of Herakleitos’ “panta rhei” and his pre-dialectical thinking in polarities. From there, a bridge can be built to Leo Tolstoy’s narrative technique of the “stream of consciousness” and his speculations on time and history in the context of his novel “War and Peace.” The Russian novelist was particularly fascinated by Zenon’s time paradox (Achilles and the Tortoise). Furthermore, this contribution is concerned with Herakleitos’ model of circulations and dualities in the mytho-poetics of Russian Symbolism around 1900 (Viacheslav Ivanov, Andrey Bely, Konstantin Balmont) and, above all, with Russian poetry of the absurd (Daniil Kharms, Aleksander Vvedenskii) and the concepts of nothingness, of infinity in the context on this side of the categories of space and time (“cisfinite poetry”), and with the spirit of the time paradox of Zenon.

The Third Renaissance and the Pre-Socratic Parmenides in Russian Modernism and Avant-Garde (2022)

Grübel, Rainer

This article aims to reconstruct the reception of pre-Socratic philosophy, especially that of Parmenides, in Russian modernism and avant-garde literature. In doing so, it places this reception into two contexts: the contemporary discussion of pre-Socratic ideas in Russian, European and American philosophy, on the one hand, and the proclamation of a third, a Russian and/or Slavic Renaissance, on the other. This Renaissance has been conceived as the intense discussion and reconsideration of ideas, notions, and expressions of ancient Greek thinking. It aimed also to avoid the reduction of Greek philosophy to Plato, as had been practiced by the Russian Orthodox Church and largely pushed through in Russian culture. One of the main points of this reconsideration concerned the quest of the relation between the word, the process of thinking, and human life, while another one connected with it involved the (re-)establishment of a close bond between the poetic word, its meaning, and its sense. The integration of this productive discussion with pre-Socratic Greek philosophy enriches and improves our knowledge of Russian modernism and avant- garde literature.

The Poet as Fate: Schopenhauer’s Literary Vision (2022)

Dowthwaite, James

The claim that a thinker concerned with the development of a totalizing metaphysical system can be a literary philosopher may seem hard to justify. For Arthur Schopenhauer, the entire world is the representation or appearance of the will to life, the metaphysical essence of all being. And yet, because this will must always appear and always take form, it is only formally that we can grasp it, only in concrete instances. For this reason, the poet “shows us how the will behaves under the influence of motives and reflection. He presents us this for the most part in the most perfect of its appearances” (WWRII, 310). In this paper, I will argue that Schopenhauer founds a philosophical approach which comes to rest on literary foundations and which alights at key moments on the strength of his literary as well as his philosophical forebears. I will do this by means of looking at how Schopenhauer treats the concept of fate. It is my contention that the fatalism inherent in Schopenhauer’s ethics is a direct result of a fundamentally literary approach to the concept. This enables us to conceive of fate from a literary and not solely from a metaphysical standpoint. I will begin by outlining the place of the literary in Schopenhauer’s philosophy, including a brief account of those writers whose work he incorporates into his analysis, and then I will demonstrate its relation to his fatalism.

Affecting Pastoral Dialogues: An Ecocritical Reading of Seamus Heaney’s Eclogues in “Electric Light” (2001) (2021)

Rozzoni, Stefano

Pastoral serves as a keyword when understanding Seamus Heaney’s literary production, both in terms of stylistic features and imagery. Although critical attention has focused on the connection between his pastoral works and contemporary Irish politics, the growth of ecocritical scholarship in the last few decades has made evident the importance of broadening such an analytical scope to relationships between humans and the environment while studying this genre. In this alignment, the present essay offers an ecocritical reading of some selected pastoral poems by Heaney, with a specific focus on his revival of the eclogue through the collection “Electric Light” (2001). Precisely, the poems “Virgil: Eclogue IX,” “Bann Valley Eclogue,” and “Glanmore Eclogue” will be read through the innovative perspective offered by the recent engagement of affect theory with ecocriticism: by doing so, I argue that Heaney’s poems can be understood as valuable nature narratives that stress the connectedness between the human and the nonhuman, while resonating with the urgencies posed by the current environmental crisis to re-think more ethical forms of relationships between them. Furthermore, through the lens of econarratology, attention will be paid to the ecological potentials expressed by the formal features of the eclogue: this observation considers, on the one hand, the notion of ‘relationality’ within the practice of the shepherds’ dialogue/singing and, on the other hand, how this literary form stresses the attachment between the human and the environment, both in the real world and in the storyworld. Hence, when exceeding a strictly politically oriented critical analysis of his work, Heaney’s eclogues become visible as compelling ecocritical accounts that favor investigating the role of (pastoral) literature in fostering critical discussions about human/nonhuman ethics as a way to respond to the challenges of the Anthropocene.

The Relationship between the Art of the Word and the Illiterate Manual Arts in Nicholas of Cusa’s Conception of the Arts (2021)

González Ríos, José

The concept of art is a lens through which one can explore the thought of Nicho las of Cusa. He uses this notion throughout his work in order to address the pro ductive dynamism of the divine mind as well as the human mind. With a focus on the human arts as likenesses of the divine art, this paper studies the relationship between the art of the word and the illiterate manual arts. Firstly, we examine the ars coniecturalis as a human art form that Cusanus presents for the first time in extenso in “De coniecturis”. Secondly, we address the power of the art of the word through the production of its most precious form, the spoken word. Thirdly, and finally, we inquire into the power of the manual arts through the example of the idiota’s making of wooden spoons in the “De mente” in order to show the relationship between this art and the art of the word.

The Conjectural Art as Self-Knowledge and Knowledge of Others: Tradition and Innovation (2021)

D'Amico, Claudia

In the last chapter of “De coniecturis”, Cusanus exhorts his friend, Cardinal Giuli ano Cesarini, to get to know himself. This classical philosophical topic is revisited by Cusanus here in an original manner. On the one hand, Cusanus’ perspective reveals the strong influence of Proclus, which deserves to be highlighted. On the other, unlike Proclus, Cusanus asserts that self-knowledge is explicitly linked to the topic of the human being as created ad imaginem and that of the world as the sphere of contraction. Cusanus bases both subjective matters on the triune princi ple. According to him, the Divine Trinity is the exemplar that cannot be reached by an image, and the effort to reach the Trinity constitutes the basic requirement for the conjectural construction of the self. Furthermore, the fact that this under standing of the Trinity implies a distinction in itself makes the Trinity the princi ple of all difference or otherness in plurality. Cusanus concludes that the image can only be constructed relationally, that it is not possible to attain God without a fundamental knowledge of the self as an image, and that no one knows his own self without knowing others at the same time.

Public Poetry: Encountering the Lyric in Urban Space (2021)

Benthien, Claudia

This paper explores the presence of the poetic word in contemporary urban settings: from “Poetry in Motion,” displayed in the New York City subway at the very place where one usually finds ads, to fluid xenon light projections of huge verse on the exterior of buildings in Basel or Zurich by visual artist Jenny Holzer, who presents poems of the Nobel Laureate Wisława Szymborska together with her own short “Truisms.” Or from single poems permanently written on walls – e.g. a much-discussed concrete poem by Eugen Gomringer at the facade of a Berlin college of education – to the technically enhanced spoken word, audible from far away as a side effect of gigantic poetry slam events in stadiums, e.g. the Trabrennbahn (race-course) in Hamburg and even performative events such as Ulrike Almut Sandig’s „augenpost“ in which poems are ‘published’ on posters, flyers and free postcards in the urban space of Leipzig or declaimed on public squares in Indian metropolises through a megaphone. Such presentations of poetry in urban space are still uncommon, thus creating an aesthetic experience that differs strongly from reception in private settings or even in readings or public poetry festivals, as the poem relates to its urban surroundings.

A Trajectory of Billboard Poetry in America: From “Burma-Shave”-Roadside Advertisement to “Three Billboards outside Ebbing, Missouri” (2021)

Paul, Heike

This essay applies a Cultural Studies-approach to the multi-facetted relationship between poetry and advertisement as it emerged in the first half of the 20th century in the United States and as it became visible on billboards by the roadside. Somewhat paradoxically, public poetry in advertising appeared all across the United States (predominantly along highways in rural areas) around the time that much of modernist American poetry was being declared a highly elitist and urban centric affair in the orbit of new criticism-scholarship at universities. My first case study addresses the iconic Burma-Shave Billboard Poetry Campaign (1929-1963) and its long-lasting influence on American (popular) culture – in literature, music, visual art. Prior to this campaign as well as on the heels of it, billboards and billboard poetry were taken up to a minor extent in poetry circles and literary criticism (where they continued to be mostly viewed with disdain) and to a larger extent by conceptual artists who used billboard aesthetics, slogans, and short (poetic) texts in installations mimicking and critiquing consumer culture. One of the most aesthetically innovative recent ‘returns’ of billboard poetry, however, is the one employed intra-diegetically in the Hollywood film “Three Billboards Outside of Ebbing, Missouri” (2017), my second case study. Here, the writing on the billboard-walls make those aspects explicit that have been submerged in the earlier rhymes by the roadside: While the playful, optimistic lines of advertisement imply, time and again, a happy white middle-class American family with a sober and well-shaved patriarch behind the wheel and thus gloss over the disavowed underside of mobility, the film makes the latent manifest and points to systemic / structural violence, such as a pervasive American rape ‘culture’ which is linked to the car and the mobility it offers. The film uses the billboard and its inscription as foil and as catalyst to address and to protest this and other forms of violence and thus presents an activist intervention in order to ask for more than merely poetic justice.

Political Video Poetry in Russia: Eco-Social Turn and Biopoetics (2021)

Smola, Klavdia

In this article, I analyze the most recent Russian video poetry as an amplification and semantic enrichment of the classic literature paradigm. My thesis is that new visual poetry produces a subtle, polysemous – but at the same time striking – political message within a synthetic artistic framework. I show how recent Russian social (also to be called political) poetry is developing what I call the aesthetics of environmental non-division. I focus on the art collective “The Group of Esfir’ Shub,” which was founded in 2017 by the artist and designer Polina Zaslavskaia. The group’s synthetic method of working with poems generates a “tropic connection between the text and the video,” which correlates or even confronts direct and figurative sign meanings of different media with each other. “Esfir’ Shub” emphasizes one of the essential features of new social poetry ‒ the problematization of corporeality as a phenomenon belonging to organic, living material, which affects the very character of subjectivity. The project “Esfir’ Shub” is situated on the border between visual eco-art and social poetry. What is more important, it represents new trends in Russian engaged aesthetics, which I call biopoetics ‒ a notion which has been intensely discussed in the last two decades.

Making it News in Contemporary Poetry (2021)

Edmond, Jacob

This essay identifies a shared response to news media in poetry written over the past three decades by writers working in Chinese, Russian, and English. These poets often directly incorporate texts and images from news media into their work. Some scholars have argued that this tendency towards the collaging of texts derived from news and social media reflects a shift in poetic subjectivity. However, when seen from a comparative perspective, these and other cut-ups of news and social media are better understood as, on the one hand, an extension of a much longer tradition of literary and artistic responses to the news and, on the other, a renewal of that tradition in response to the intensification of the intertwined pressures of new media and globalization since the end of the Cold War and the rise of the Internet. The article identifies this shared response to media and globalization among a variety of examples in Chinese, Russian, and English, including Kirill Medvedev’s «Текст, посвященный трагическим событиям 11 сентября в Нью-Йорке» (“Text Devoted to the Tragic Events of September 11 in New York”); Stanislav Lvovsky’s «Чужими словами» (“In Other Words”); Dmitri Prigov’s «По материалам прессы» (“Based on Material from the Press”) and “ru.sofob (50 x 50)”; Lin Yaode’s 林燿德 “Er erba” 《二二八》(“February 28”), Hsia Yü 夏宇 and her collaborators’ group project “Huadiao huadiao huadiao” 《劃掉劃掉劃掉》 (“Cross It Out, Cross It Out, Cross It Out”), Yan Jun’s 顏峻 2003 multi-media video performance “Fan dui yiqie you zuzhi de qipian” 《反对一切有组织的欺骗》 (“Against All Organized Deception”); online video poetry produced in response to the 2008 Sichuan earthquake; and Brian Kim Stefans’s mashup of “New York Times” articles with texts from the Situationist International. On the one hand, these texts operate between various media and art forms: between poetry and contemporary art, music, journalism, and social media, between the print newspaper and digital file, between the webpage and live performance, and between image and text. But on the other hand, and inextricably, they also operate within global information networks. They are better understood as addressing not the transformation of the poetic subject but the undoing of the boundaries of poetry and of the concept of a nationally defined literature.

From Book Poetry to Digital Poetry (2021)

Larsen, Peter Stein

In the article, I will discuss the relationship between ‘book poetry’ and ‘digital poetry.’ I examine the differences, as well as the similarities, between poetry as presented in these two media. Research on the transition from book poetry to digital poetry has mainly focussed on the significant changes in genre and work concepts as well as in the author and reader roles. However, several trends within the tradition of poetry have intensified and have further developed since the emergence of the digital media. The focus in this paper will thus be on four key features, which were founded in book poetry as far back as early Modernism and the avant-garde movements, but, to a great extent, those features have unfolded in digital poetry. The four features are the multimodality, the montage form, the network structure, and the serial form. The artistic opportunities offered by digital poetry are not only due to technological opportunities in the new media. Such opportunities are just as much due to the innovations in multimodality, montages, network structures, and seriality realized by avant-garde and symbolist poets like Mallarmé, Apollinaire, Schwitters, Eliot, and Pound in early modernism. My article concludes with an example of how the four features form the basis for a work of digital poetry, namely Johannes Heldén’s “The Primary Directive” (2008).

New Dynamics: Chinese Women’s Poetry Enacted (2021)

Jaguścik, Justyna

The article offers a preliminary investigation of the phenomenon of female-authored ‘poetry theater’ (shige juchang)1 in the People’s Republic of China. It discusses cross-genre explorations by a group of female poets, theater directors and artists who are all associated with the movement of ‘women’s poetry’ (nüxing shige) that emerged in the 1980s in China. The discussion focuses on two performances based on female-authored poems, “Riding a Roller Coaster Flying Toward the Future” (2011) and “Roaming the Fuchun Mountains with Huang Gongwang” (2016), which resulted from the joint efforts of four women: the poet Zhai Yongming, the poet-scholar Zhou Zan, and the theater directors Cao Kefei and Chen Si’an. Their avant-garde experiments with poetical theater document the different ways in which poetry is being translated into images, sounds, or bodily movements on stage. The paper argues that poetic exploration of writing and reciting practices has gained new momentum from emerging intermedial, visual-verbal experiments. Furthermore, it claims that interest in ‘poetry theater’ is also driven by the search for new forms of cross-genre stage performances that could be different from the previously politicized or commercialized ones.

Contemporary Russian Poetry and the Musical Avant-Garde: Performative Intersections (2021)

Kukulin, Ilya

This paper is focused on a relatively new phenomenon: joint performances by poets and avant-garde (primarily electronic) musicians in contemporary Russia. In part, these performances are reminiscent of performances by American and Western European poets with jazz ensembles in the 1960s and 1970s. At that time in the Soviet Union, this practice was almost unheard of: when intermedial experiments did take place, poets – particularly the so-called “official” poets – turned not to music but to theatre. The most important elements of these performances were their emphases on virtuosic improvisation, the theatrical immediacy of what was taking place, and creating a community around the performer. In contrast, contemporary collaborations between poets and musicians largely demonstrate the non-self-sufficiency of their respective media and, in doing so, deconstruct the. very premise of the poetic (lyric) subject. My contention is that intermediality as such – in this case, the interaction between music and poetry – could thus be the most important tool available for creating a “poetry without a subject.” Moreover, in practice, it has acquired a salient social and political meaning in modern Russia: depicting culture as a space of individualized dialogues and polylogues.

Qui chante? The Lyric’s Voice as Impersonation (2021)

Austenfeld, Thomas

Starting from the imperative to not just read, but to speak lyric poems out loud, this paper considers ways in which poems change depending on who utters them. Beyond the familiar distinction between the poem’s author and the lyrical ‘I’ – the voice in which the poet chooses to utter the poem – any performer who speaks a poem also impersonates the text. Reading is the first act of interpretation; others follow. Sound is an indispensable constitutive aspect of the lyric poem, too often neglected. Each reading of a poem can turn into a momentary ec-stasis.

Generic Extensions in Contemporary British Poetry (2021)

Hühn, Peter

This contribution analyses two complex examples of the generic extension of lyric poetry in recent British literature. Tony Harrison’s film poem “The Shadow of Hiroshima” (1995) expands the lyric text into the visual dimension; Glyn Maxwell’s collection “The Sugar Mile” (2005) arranges a large number of individual lyric poems into a dramatic scenario. In both cases the generic transition is coupled with a further generic extension – the elaboration of a distinctly narrative sequentiality. In two important aspects the generic extension of these examples affects the rendering of a particular experience, namely the perception of and reaction to massive violence and destruction. One aspect concerns the organization of speech situation and perspective, especially the relation between a superordinate authorial voice and possible subordinate voices, the other aspect pertains to the status of the represented experience in the ambiguity between factuality and fictionality, characteristic of the stance of the lyric utterance in various periods throughout the history of poetry. In both respects the generic expansion in Harrison’s “The Shadow of Hiroshima” and in Maxwell‘s “The Sugar Mile” can be shown to utilize the representational potentials of lyric poetry in distinctly alternative directions.

The ‘Novel in Poems’ – An Emerging Genre (2021)

Stahl, Henrieke

A new genre has emerged in contemporary literature: the ‘novel in poems.’ This genre hybridizes the novel and poetry in order to construct characters and a plot through relatively autonomous poems in series. The ‘novel in poems’ appears in different subtypes, which can be categorized according to the following criteria: (1) the presence of one speaker versus several speakers, (2) the presence of a speaker as lyric protagonist and/or narrator, and (3) the presence of a blend of distinct modes of lyric, narrative, and dramatic representation in various forms of combination. Specific characteristics of the ‘novel in poems’ are: 1) variation of constituent poetic forms with different degrees of semantic autonomy and brevity; 2) hyper-structuring through symmetries, holism, and equivalences; 3) a tendency to differentiate mediating instances within the text; 4) the reduction or elimination of the narrator or of narrative principles and the use of an omnipresent textual subject; 5) the presence of metapoetic reflections on topics such as poetry and creativity; 6) an emphasis on voice, person, and subjectivity; 7) episodic plot construction through montage techniques and a tendency toward chronological order; 8) the predominance of present speech and action; 9) contradictions between the speaker as subject and addresser, via the lyric fiction of performativity, and the function of narration; 10) a necessity imposed upon the reader to reconstruct the plot and characters. This essay establishes three subtypes within the proposed genre: a lyric ‘novel in poems’ with one speaker (Irina Ermakova), a polyphonically narrative ‘novel in poems’ that combines third-person narration with several alterior speakers (Lana Hechtman Ayers), and, finally, a dramatic ‘novel in poems’ with shifting primary speakers (Glyn Maxwell).

A Gap in(to) the Dictionary: The In-between Lyric of Tawada Yōko (2021)

Böhm, Jasmin

The work of Japanese-German writer Yoko Tawada (Tawada Yōko) stands out as an example of ‘in-between’ writing. Instead of simply ‘translating’ Japanese into German and vice versa, Tawada blends both languages and cultures, often self-reflexively. As a result, poetic in-between spaces emerge, in which creative work, cultural translation, and social criticism can take place. The texts also construct in-between spaces on a formal level. For instance, the verse novels “Kasa no shitai to watashi no tsuma” (『傘の死体とわたしの妻』, 2006) and “Ein Balkonplatz für flüchtige Abende” (2016) feature both narrative progression and poetic devices (vivid imagery, association, and wordplay), defying categorization either as volumes of poetry or as novels. In addition, the in-between space of genres becomes visible in Tawada’s self-translations, which often amount to rewritings and lead to a change in genre – travel essay to novella, novel to drama, or poem to prose text. An example of this genre-transcending bilingualism as entryway to an in-between space are the texts „Die Orangerie“ (1997) and “Orenji-en nite” (「オレンジ園にて」, 1997/1998), which initially appear as a poem and its (apparently) prose translation. However, a number of textual peculiarities of both pieces point to the mutual influences between versions. Thus, I read all four examples as hybrid forms of poetry, which perform the mixing of genres, languages, and cultures that occurs in today’s world. In their cultural hybridity especially, the poems point to underlying social issues of homo- and xenophobia.

Contemporary Lyric Poetry in Transitions between Genres and Media (2021)

Müller, Ralph ; Stahl, Henrieke

More than any other literary form, contemporary poetry is in transition: interspersed with narrative and dramatic genres, combining prose and verse, and even incorporating other media, such as visual arts, music, film, and digital technology. It shifts the borders between public and private spheres, aesthetic and discursive approaches, and producer and recipient. On the basis of case studies, this issue addresses the challenges of poetry in transition and stimulates new approaches in lyric theory and methodology.

Fugitive Place-Making in Black London: Urban Struggles, Care, and Refusal (2026)

Adscheid, Toni Wilhelm

Transnational protest movements continue to expose the enduring legacies of colonial exploitation and institutionalised racism within and beyond European cities. They foreground the systemic conditions under which Black lives are rendered disproportionately vulnerable to premature death. In doing so, they expose the enduring entanglements of racial capitalism, state violence and spatial exclusion. Through their ongoing political agitation these movements highlight the need for spatio-temporally situated and relationally embedded engagements with Black urban lives. My thesis responds to that call by examining place-making practices of enclosure and refusal throughout Black London’s post-World War II development. Grounded in the ethnographic narrative of “being halfway while shooting”, I explore how Black lives are enclosed by institutional racism, how this enclosure is spatialised and how Black and differently racialised Londoners refuse these spatial enclosures through everyday and collective place-making practices. At the intersection of structural constraint and the desire to enact Black freedom in London, I specifically foreground the emergence of fugitive place-making practices. Conceptually, I bring (critical) urban geography scholarship, Black studies and Black (British)Geographies scholarship into conversation. I develop “being halfway while shooting” as a relational concept that foregrounds the production of racialised urban knowledges, the multiplicity of Black enclosures, and the plurality of place-based strategies committed to refusal. I do so by stressing the relevance of Black fugitive thinking to account for the ongoing refusals that mark the relationship between Blackness and the British city. Methodologically, I adopt a research-activist ethnographic approach, grounded in my long-term engagement with a housing campaign in East London that organises around the housing needs of London’s racialised and gendered urban poor. Using qualitative methods - archival research, interviews, (non-)participant observations, document and media analysis - I embed contemporary struggles into long and ongoing histories of racial-capitalist urban development as well as Black and multi-ethnic refusal. The empirical chapters trace place-making practices of enclosure and refusal across London’s post-World War II urban development. By examining the aftermath of urban revolts and changing urban welfare regimes, I explore how racialised urban governance has been historically materialised in and through the city. At the same time, I foreground how within this racialised construction of the British city, Black and differently racialised Londoners continue to hold open the possibility of refusal through places in which communal care and self-determination can be enacted. I then turn to the struggle over housing in East London, showing how contemporary processes of racialised dehumanisation and ongoing displacement are both historically rooted and actively contested. In the final empirical chapter I accentuate the relevance of these findings for German-speaking critical urban geography debates. The research shows that racial capitalist urbanism reproduces enclosures through practices of value extraction, spatial displacement, and the policing of Black subjectivities. In response, Black and differently racialised Londoners engage in fugitive place-making. Rooted in communal care, political organisation, collective education and cultural affirmation, these practices reassert Black presence and belonging. They offer an enduring mode of place-based refusal and the ongoing possibility to stay in the city differently. These findings not only demonstrate the academic significance of my research but also underscore the urgent need to support the place-making practices of Black and differently racialised urban communities, who continue to refuse the racialised enclosure of the British city from within. From these empirical insights, I propose the concept of a fugitive sense of place - a theoretical lens that accounts for the racialised reproduction of urban space and the transformative place-making practices of those who refuse its logics. Rather than offering prescriptive policy recommendations, I call for a reorientation of urban geographical enquiry by centring Black spatial practices, knowledges and imaginations. Through the lens of “being halfway while shooting”, I argue for a rethinking of human habitation and urban theory through the lived experiences of Black survival and refusal. Attending to a fugitive sense of place, I propose new avenues for human geography research to explore how fugitive place-making practices reshape the meanings, conditions, and possibilities of urban life.

Essays on Income, Wellbeing, and the Labour Market (2026)

Clemens, Marco

Income composition can have a significant impact on workers’ well-being, productivity, and career paths. Wages often include a variety of components, such as unconditional bonuses, profit-sharing payments, and incentives based on the individual performance of employees. Each of these may influence employee labour outcomes differently and the worker composition may matter for managers when designing the salary package. Simultaneously, workers’ employment choices and well-being are influenced by income outside the job, such as inheritances and lottery winnings, as well as by external factors like technological change. This dissertation includes five empirical studies that investigate these issues, yielding new insights on the role of monetary gifts, financial incentives, labour market institutions, and technology disruptions in affecting employees’ labour and well-being outcomes.

Implicit Motives in Childhood and Adolescence - Findings on Developmental and Psychological Correlates (2026)

Kerpen, Ellen

The role of implicit motives for affective, cognitive and behavioral processes has been a focal part of psychological research for decades. Yet, the majority of research in this field has been concentrated on processes involving implicit motives in adulthood. The systematic investigation of developmental correlates of implicit motives remains largely uncharted. The studies cumulated in this thesis aim to add to the sparse research on implicit motives in childhood and adolescence. Specifically, the development of the implicit power motive in the transition of middle to late childhood as a function of parenting behavior (Chapter 4), the predictive value of the implicit achievement motive for objective swimming performance in children and adolescents (Chapter 5) and the role of motive congruence for successful goal realization in adolescent samples across two cultures (Chapter 6) were investigated. Results of Study 1 (Chapter 4) indicate a negative longitudinal association of authoritarian parenting with the implicit power motive in children that is moderated by children’s perception of psychologically controlling parenting. Study 2 (Chapter 5) extends existing research on the assumed positive association of the implicit achievement motive and sports performance and demonstrates the moderating role of competitive anxiety on this association. Finally, Study 3 (Chapter 6) illustrates a moderating effect of implicit motives on the association of goal commitment and successful goal realization in German and Zambian adolescents, however, this effect was only observed in the domain of power motivation. Findings from all three studies are discussed in the context of the significance of implicit motives for psychological research.

From education to employment: Understanding educational mismatch using the case of Germany (2026)

Geißler, Theresa Regina

Many developed countries, including Germany, face a steady rise in the share of individuals obtaining higher education. While rising education itself bears a series of advantages as extensively studied in previous literature, it is also conceptually linked to a higher likelihood of working in an occupation that does not match one’s normal qualifications. Previous studies have predominantly evaluated how demographic or job‐related aspects correlate with the likelihood of being educationally ﴾mis﴿matched. However, they have largely ignored institutional facets of the educational system or industrial organization. Moreover, little is known about how private wealth affects educational mismatch or whether job satisfaction is homogenously affected among individuals once such a mismatch occurs. The five projects collected in this thesis aim to answer these open questions in the literature for Germany, using data from the Socio‐Economic Panel and employing different time intervals between 1984 and 2022. Beginning with the educational system in early childhood, Chapter 2 evaluates the impact of school‐starting age on the likelihood of over‐ and undereducation. It exploits the exogenous variation in school‐entry rules across federal states and years in Germany with regression discontinuity designs. The results report a negative impact of school‐starting age on the likelihood of undereducation, but no systematic relationship with overeducation. Subsequently, Chapter 3 explores the variation in education costs by leveraging the quasi‐experimental setting induced by the time‐limited introduction of tuition fees in several German federal states between 2006 and 2014. The increase in education costs among treated graduates results in a significantly higher likelihood of overeducation, which endures even several years post‐graduation. Chapter 4 focuses on the industrial relations system and examines the correlation between trade union membership and the likelihood and extent of educational ﴾mis﴿match. The results reveal that trade union members report significantly less overeducation at both the intensive and extensive margin and also a higher likelihood of being matched compared to non‐members. Furthermore, the heterogeneity analysis provides evidence that this correlation is driven by improved bargaining power instead of informational advantages. Chapter 5 focuses on private wealth as a determinant of educational mismatch by investigating the impact of a wealth shock through inheritances, lottery winnings or gifts on the likelihood of over‐ and undereducation. Due to the diminishing marginal returns of wages with increasing windfall gains the likelihood of undereducation is expected to decrease, while that of overeducation is expected to increase. Empirically, these suppositions are supported for overeducation, as its likelihood increases significantly after the windfall gain. Further analyses reveal that this effect is driven by individuals switching occupations while increasing their leisure time, and it materializes only for medium to large windfall gains. Contrary to the previous chapters, Chapter 6 focuses on educational mismatch, more precisely on overeducation, as the independent variable. In particular, it investigates the correlation between overeducation and job satisfaction. The results align with the previously established negative correlation for private sector employees exclusively. In contrast, interaction and subsample analyses reveal a positive correlation for public sector employees. This link is driven by individuals with a high degree of altruistic motivation and family orientation.

Unlocking Personal Power: Exploring Individual Differences in Self-Regulation through Action versus State Orientation (2026)

Waldenmeier, Karla

This dissertation examines how individuals unlock their personal power by investigating individual differences in self-regulation, in particular, how situational conditions interact with the personality dispositions of action versus state orientation. Action-oriented individuals are well able to regulate their affective states and to bridge the intention–behavior gap, showing initiative, implementing demanding intentions, and resisting temptations. State-oriented individuals, by contrast, often struggle to regulate affect and experience difficulties enacting intentions, especially under demanding conditions, tending to hesitate and ruminate. While extensive research has highlighted the advantages of action orientation across various domains such as education and health, this thesis challenges the prevailing one-sided perspective that presents action orientation as inherently superior and frames state orientation negatively. Drawing on Personality Systems Interactions theory, the dissertation adopts a dynamic view that understands these dispositions as context-sensitive rather than fixed. The central assumption is that action and state orientation each require different kinds of situational conditions to fully unlock their potential. Across six empirical studies (overall N = 1,067) using a multimethod approach that combines experimental and survey-based research in diverse populations and contextual settings, this dissertation examines (1) action and state orientation as distinct dispositions, (2) their dynamic interaction with situational factors, and (3) ways to support each in mobilizing personal power. Overall, the findings show that each disposition offers unique advantages - they simply require different situational conditions for their potential to unfold.

Methods to Coordinate Survey Samples in the Context of German Business Statistics (2025)

Straubinger, Johannes

Measuring the economic activity of a country requires high-quality data of businesses. In the case of Germany, this is not only required at national level, but also at federal state level and for different economic sectors. Important sources for high-quality business data are the business register and, among others, also 14 business surveys which are conducted by the Federal Statistical Office of Germany. However, the quality requirements of the Federal Statistical Office are in contrast to the interests of the businesses themselves. For them, answering to a survey's questionnaire is an additional cost factor, also known as response burden. A high response burden should be avoided, since it can have a negative impact on the quality of the businesses' responses to the surveys. Therefore, sample coordination can be used as a method to control the distribution of response burden while securing high-quality data. When applying already existing business survey coordination systems, developed by different statistical institutes, legal and administrative standards of German official statistics have to be taken into account. These standards consider different sampling fractions, rotation fractions, periodicity, and stratification of the aforementioned 14 business surveys. Therefore, the aim of this doctoral thesis is to check the existing business survey coordination systems for their applicability in the context of German official statistics and, if necessary, to modify them accordingly. These modifications include the introduction of individual burden indicators which aim to take the individual perception of response burden into account. For this purpose, several synthetic data sets have been created to test the application of the modified versions of the different business survey coordination systems through Monte Carlo simulation studies. These data sets include a large panel data set, reflecting the landscape of businesses in Rhineland-Palatinate and three smaller, synthetic data sets. The latter have been created with the help of the R package BuSuCo which has been developed within the scope of this thesis. The above mentioned simulation studies are evaluated based on different measures for estimation quality as well as for the concentration and distribution of response burden.

Algorithms and Complexity Theory for Bilevel Problems with Nonlinear Lower Levels (2025)

Horländer, Andreas

Bilevel problems are optimization problems for which parts of the variables are constrained to be an optimal solution to another nested optimization problem. This structure renders bilevel problems particularly well-suited for modeling hierarchical decision-making processes. They are widely applicable in areas such as energy markets, transportation systems, security planning, and pricing. However, the hierarchical nature of these problems also makes them inherently challenging to solve, both in theory and in practice. In this thesis, we study different nonlinear problem settings for the nested optimization problem. First, we focus on nonlinear but convex bilevel problems with purely integer variables. We propose a solution algorithm that uses a branch-and-cut framework with tailored cutting planes. We prove correctness and finite termination of the method under suitable assumptions and put it into context of existing literature. Moreover, we provide an extensive numerical study to showcase the applicability of our method and we compare it to the state-of-the-art approach for a less general setting on suitable instances from the literature. Furthermore, we discuss challenges that arise when we try to generalize our approach to the mixed-integer setting. Next, we study mixed-integer bilevel problems for which the nested problem has a nonconvex and quadratic objective function, linear constraints, and continuous variables. We state and prove a complexity-theoretical hardness result for this problem class and develop a lower and upper bounding scheme to solve these problems. We prove correctness and finite termination of the proposed method under suitable assumptions and test its applicability in a numerical study. Finally, we consider bilevel problems with continuous variables, where the nested problem has a convex-quadratic objective function and linear constraints. We reformulate them as single-level optimization problems using necessary and sufficient optimality conditions for the nested problem. Then, we explore the family of so-called P-split reformulations for this single-level problem and test their applicability in a preliminary numerical study.

Unveiling Extracellular Enzyme Activities in Aquatic Biofilms by Innovative Methodological Approaches for Ecological Research (2025)

Riese, Maria

Extracellular enzymes in microbial communities play a central role in nutrient cycling and the degradation of (pollutant) substances in various natural and anthropogenic systems. Bound in aquatic biofilms, sludge aggregates, or even unbound at their interfaces, they are of great importance for both the environment and human health. In particular, in wastewater treatment plants and inland waters, hydrolytic activities influence the wide-reaching efficiency of nutrient removal and self-purification, thus contributing significantly to overall water quality. The main goal of this dissertation project was to investigate the factors that influence enzymatic activity and the health of microbial communities in activated sludge and river systems, particularly in relation to anthropogenic influences and natural environmental conditions. The aim was to contribute to a better understanding of the sensitivity of our freshwater ecosystems and to support the long-term preservation of water quality and ecological stability. The development and optimization of appropriate methods, as well as their testing and applicability, were the focal points. For this purpose, a fluorometric microplate assay was developed and adapted to determine both extracellular enzyme activities (EEAs) in activated sludge samples and in intact biofilms. Its suitability for field studies was subsequently tested. Inhibition and activity of selected hydrolases under different conditions were investigated to better understand the mechanisms and potential environmental risks posed by anthropogenic influences and seasonal fluctuations of hydrochemical and climatic parameters. The first phase of the doctoral thesis involved studies on the inhibition of alkaline phosphatase in activated sludge by oxyanions. Using the fluorometric microplate assay, the inhibitory effect was sensitively detected over a pH range of 7.0 to 8.5. IC50- and IC20-concentrations were calculated from modeled dose-response functions. It was found that vanadate and tungstate caused strong inhibitory effects, while molybdate moderately inhibited the enzyme. An increasing pH led to a reduction in the inhibitory effect of tungstate and molybdate. The inhibition effects of vanadate were not significantly affected by the pH. In municipal wastewater, the concentrations of such metal ions are usually low, but industrial wastewater may have pollutant loads that can significantly impact the removal of phosphorus-containing compounds, and thus the efficiency of treatment plants. In the second phase, an attempt was made to further adapt the developed methodology to investigate EEA and kinetics in intact freshwater biofilms. Four different types of bead materials (lava, glass, sintered quartz, and ceramics) fitting into a 96-well microplate were tested as carriers for biofilms on both the laboratory and field scale. The analysis included a total of seven hydrolases as representatives of key nutrient cycles such as phosphorus, carbon, and nitrogen: phosphatases, glucosidases, peptidases (two different types), and sulfatase. Experiments with increasing substrate concentrations led to classical kinetic profiles according to the Michaelis-Menten mechanism. This allowed for the prediction of the biofilm enzymes’ response to different substrate concentrations. Parameters such as Vmax and Km could be derived from the modeled curves. Ceramic beads are particularly suitable for long-term studies due to their high stability, while sintered quartz beads should be preferred for the use in stagnant media (material loss under turbulent conditions). Lava and glass beads, on the other and, proved suboptimal for uniform biofilm development due to their surface properties. The potential use of this fast and sensitive test for ecotoxicological or even human-toxicological studies was demonstrated by the effects of caffeine on the activity of PDE. The result of this part of the research represents a powerful tool for assessing environmental pollution and monitoring water quality. The high application potential was clearly highlighted in the final phase of the project. The goal here was to deepen the understanding of interactions between seasonal factors, anthropogenic influences, and biofilm processes in rivers by investigating EEA and biofilm parameters such as biomass and relating them to hydrochemical and climatic factors. Ceramic beads were exposed both upstream and downstream of a wastewater treatment plant discharge and sampled over a period of seven months. EEAs and biomass varied depending on the season and location, with higher microbial activity observed upstream in winter. Winter conditions led to the dilution of most nutrients as well as in an increse of dissolved oxygen. Nutrient concentrations analyzed downstream were significantly higher in the summer. Accumulation of nutrient or pollutants during the summer months cannot be excluded, which may have led to a general reduction in enzyme activities. Potential causes could be inhibitory effects on the enzymes, or a reduced enzyme activity due to a sufficiently high nutrient supply. In general, the sampling site upstream showed a more pronounced seasonal dynamics, with a significant proportion of the variance in biological parameters (activity and biomass) attributable to seasonal factors. A secondary component, likely reflecting the impact of the treatment plant discharge, explained another portion of the data variance. Regardless of the season, high correlations between biological parameters were observed upstream, while downstream the data were more decorrelated. This could be because the biofilms, under chronic stress, respond less dynamically to seasonal fluctuations. This dissertation illustrates that in addition to anthropogenic stress factors, seasonal fluctuations of hydrochemical and climatic parameters should also be considered in "stress downstream the pipe" studies. The selected methods are recommended for explaining and considering the data variance, as they highlight the complex interplay between microbial enzymatic activity, environmental factors, and pollutants in the activated sludge of wastewater treatment plants and also in aquatic systems. The novel bead assay could pave the way for the future standardization of effect-oriented studies on intact aquatic biofilms.

Perennial grain cultivation as a nature-based solution for resilient agriculture suggested by soil bioindicator analysis (2025)

Förster, Alena

Perennial crops eliminate soil disturbance and reduce the amount of synthetic chemicals that are applied to the soil, improving soil biodiversity and food web structure. Additionally, perennial cropping is characterised by all year-round surface coverage which benefits soil biota in terms of habitat and food sources. Perennial intermediate wheatgrass (Thinopyrum intermedium, IWG) was domesticated and commercialised by The Land Institute in Kansas as Kernza® and serves as an example for these nature-based solutions. It develops an extensive root system that has a higher nutrient retention, possibly reducing nutrient runoff. It thereby follows a more resource-conservative strategy with improved belowground-oriented resource allocation in its root system. This may reduce the need for excessive fertiliser as the crop has a higher nitrogen efficiency, among other things. IWG promoted the earthworm community and its diversity, more specifically, the occurrence of epigeic species (litter inhabitants), since those species benefit from the increased soil coverage and elimination of disturbances in the soil. As IWG creates a dense and extensive root system, as shown by the increased occurrence of root-feeding nematodes, endogeic species (horizontal burrowers) are supported through the provision of a reliable food source. IWG was characterised as a mostly undisturbed system with a highly structured food web through nematode analysis, as expressed through the promotion of structure indicators, for example, that are sensitive to disturbances in the soil and are therefore supported under no-till management. The root microbiome is continuously being shaped by the host as the crop regrows from the roots each vegetation period. This creates a symbiotic relationship and a beneficial feedback loop for the crop. Resultantly, the root-endophytic microbiome under IWG had a higher network complexity, connectivity and stability compared to annual wheat. The regrowth from the roots for IWG requires increased nutrient and energy storage, which was indicated by increased starch values. Correspondingly, the longer residence time of the roots in the soil resulted in higher lignin values. Furthermore, the decomposition pathway was dominated by fungivorous nematodes which may correspond to stimulated nutrient cycling and a heterogeneous resource environment, as seen for low input systems. Overall, perennial wheat cultivation improved soil biodiversity already after an establishment of 3-6 years. As those benefits were present for all three countries, the varying soil and climate conditions do not seem to interfere with the positive effect of perennial wheat on the soil ecosystem, demonstrating a wide transferability and adaptability of the crop onto other study sites as well. Enhanced complexity and connectivity of the food web in comparison to annual wheat may indicate a resistance against abiotic stress, suggesting IWG cultivation as a viable option for a sustainable and resilient agriculture. The improvement in nutrient cycling and the resource-efficient cultivation strategy for IWG could enable cultivation on marginal land where annual crop cultivation is not possible as the soils are susceptible to erosion and nutrient runoff. This opens up new possibilities for agricultural cultivation on previously unused land, thus contributing to food security in the future.

Analysis of the predictive capacity of machine learning techniques for climate change impact research of a lowland river compared to traditional hydrological models (2025)

Ley-Lützenkirchen, Alexander

The application of machine learning and deep learning methods to hydrological modelling has advanced significantly in recent years, offering alternatives to traditional conceptual and physically based approaches. Within the numerous algorithms, long short-term memory (LSTM) networks have proven themselves particularly useful for the task of streamflow modelling. This thesis provides a collection of publications that investigate the capabilities, limitations and interpretability of LSTM for the purpose of streamflow modelling and climate change impact assessment within the lowland Ems catchment in Northwest Germany. Within a comparative performance evaluation, LSTM and its predecessor, the recurrent neural network, demonstrate superior accuracy compared to the conceptual HBV model across various statistical performance metrics. However, a decline in performance was observed during low-flow conditions in certain sub-catchments. The evaluation of the flow duration curve revealed that the ML models more effectively capture the water balance, while HBV better represents streamflow dynamics. To enhance the interpretability of LSTM, six explainable artificial intelligence techniques were applied. These methods consistently identified seasonal patterns in the temporal relevance of hydroclimatic input data. In combination with an observed correlation between the internal LSTM states and catchment-scale soil moisture dynamics, the findings suggest that LSTM models are capable of implicitly learning the relevant hydrological processes. Following, the capabilities of LSTM to model climate change impact scenarios, particularly when they extend beyond historically observed climate conditions, are addressed. An ensemble of climate change projections is provided as hydroclimatic input to evaluate the performance of LSTMs and conceptual models. While all models reveal heterogeneous alterations in streamflow under future climate conditions, significant differences emerge based on the model type. Results provide evidence that LSTMs, in combination with the temperature-based Haude formula for estimating potential evaporation, work inadequately under altered climatic regimes, raising concerns about their applicability in long-term projections. The study also indicates the potential need to incorporate physical constraints into LSTM architectures to ensure model robustness and hydrological plausibility beyond the historical training range. Collectively, this thesis contributes important insights into the applicability and interpretability of LSTM models in streamflow modelling. Despite the presence of a physically realistic representation of soil moisture dynamics of the Ems catchment, no robust change signals for streamflow under climate change can be derived. Those results underscore the potential of LSTM model approaches for accurate streamflow simulation, however, they require us to always critically question LSTM results, particularly when they are applied outside the training range.

Simulation of emissions from pottery kilns in the Roman period (2025)

Drüe, Clemens

Present-day air quality is known through dense monitoring and extensive pollu- tion control mechanisms. In contrast, knowledge of historical pollution, particularly before the industrial revolution, is accessible only through occasional reports of singular local events and through natural archives such as ice or sediment cores that record global-scale pollution. However, the regular local to regional pollution that most affects human life is hardly known. Historical sciences have argued both for and against significant air pollution in and around historic cities and manufacturing sites. For the Roman era, it has been hypothesized that air quality played a role in several patterns of action of the period. However, to the author's knowledge, there are no quantitative studies of Roman emissions. Using the results of modern experimental archaeology, this study attempts to quantify the emissions from Roman pottery kilns and their impact on surrounding human settlements. It is shown that although the pollution did not reach today's limits, it must have approached levels known to cause adverse health effects. A series of additional test simulations have been conducted to determine how these first results might be improved in the future.

Optimization Methods for Geo-Referencing Statistical Information in Spatial Microsimulation (2025)

Moschen, Lucas

Spatial microsimulation is an important tool for integrating geographical information into the evaluation of public policies and the analysis of social phenomena in urban regions. These models simulate the behavior and interaction between units of the region, such as individuals, households or firms, under specific conditions that may or not involve projections over time. This requires a representative base data set for their respective units. In this thesis, we focus on the geo-referencing step of the population in the construction of this data set, where we define the location of the individuals so that the allocation obtained is representative in relation to the population of the region. To do this, we consider the assignment of households to dwellings with specific coordinates by solving a maximum weight matching problem where side constraints are included so that the allocation obtained satisfies statistical structures intrinsic to the considered region. The model of this problem represents each feasible assignment of household to dwelling as a binary variable, which results in billions of variables for medium-sized municipalities such as the city of Trier, Germany. Therefore, standard solvers for mixed-integer linear optimization are not able to solve it due to their high time and memory consumption. Hence, we develop two approaches capable of producing high-quality allocations using a reasonable amount of computational resources, one based on specific decomposition algorithms, and the other characterized by the application of an approximation algorithm in the framework of Lagrangian relaxation of the side constraints. We theoretically explore the allocations obtained by both approaches and perform an extensive computational study using synthetic data sets and real-world data sets associated with the city of Trier. The results show that the developed methods are able to obtain near-optimal solutions using significantly less memory and time than the solver Gurobi, which enables them to tackle significantly larger instances, with approximately 100 000 households and dwellings. Furthermore, the allocations obtained for the real-world data sets correspond to a realistic population distribution, which strengthens the practical applicability of our methods.

Three-Point Difference Schemes of High Order of Accuracy for Solving the Sturm-Liouville Problem (2025)

Khomenko, Nadiya

The dissertation is devoted to the construction and justification of three-point difference schemes of high order of accuracy for solving the Sturm-Liouville problem. A new algorithmic realization of the exact three-point difference scheme on a non-uniform grid has been developed. We show that to compute the coefficients of the exact scheme in an arbitrary grid node, it is necessary to solve two auxiliary Cauchy problems for the system of three linear ordinary differential equations of the first order. The coefficient stability of the exact three-point difference scheme is proved. If the Cauchy problems are solved numerically using any one-step method, we obtain the truncated three-point difference scheme. The accuracy estimate of three-point difference schemes was obtained and the algorithm for finding their solution was developed. We also developed a new algorithmic realization of the exact three-point difference scheme for the Sturm-Liouville problem with singularities at the ends of the interval. As in the case of the classical Sturm-Liouville problem, to find the coefficients of the exact three-point difference scheme, it is necessary to solve two auxiliary Cauchy problems for each grid node. The coefficient stability of the exact three-point difference scheme is proved. Since the Cauchy problems for the first and last grid nodes are singular, the Taylor series method has been developed to solve them. The accuracy estimate of truncated three-point difference schemes was obtained. To solve the difference scheme, the Newton's iterative method is used. Numerical experiments are presented which confirm the efficiency of the proposed approach.

Exploring the potential of the German Environmental Specimen Bank for retrospective molecular biodiversity monitoring (2025)

Junk, Isabelle

Biodiversity is threatened by a wide range of anthropogenic activities. Monitoring offers critical insights into how and why biodiversity is changing, helping to identify effective measures for maintaining biodiversity and its ecosystem services. However, conventional biodiversity monitoring methods are labor-intensive, and standardized long-term monitoring series are scarce. DNA-based approaches like metabarcoding environmental DNA (eDNA) promise rapid, cost-efficient, and highly resolved community data. At the same time, scientists are looking for alternative data sources that can compensate for the lack of long-term monitoring data to study past biodiversity changes. This work explores the potential of the German Environmental Specimen Bank (ESB), a pollution monitoring archive, which appears particularly promising for retrospective biodiversity monitoring. Biota samples from different ecosystems across the country are collected and archived at an exceptional level of standardization. Sampling species act as natural eDNA samplers, accumulating genetic traces from surrounding organisms. The cryogenic storage at the ESB preserves any eDNA in the samples in its original state. In this thesis, Chapter I serves as an introductory chapter, outlining the general chances and challenges of metabarcoding for assessing biodiversity. Chapter II focuses on primer design and testing the utility of ESB sampling species like mussels and macroalgae for characterizing the surrounding community. Both chapters form the basis for Chapters III to V, which report the use of ESB time series to uncover sample-associated communities and the changes they undergo. Chapter III illustrates the value of these time series by revealing the invasion trajectory of an alien barnacle into German coastal waters and linking the process to climate change. Chapter IV forms the core of this thesis by presenting an expanded measurement of biodiversity change in ESB time series across different taxonomic groups and ecosystem types. Here, a gradual compositional change (turnover) is reported from bacterial, fungal, microeukaryotic, and metazoan communities tending to either spatial homogenization or differentiation. Observed trends are tested for significance using a dynamic model of community ecology based on the equilibrium theory of island biogeography. The model reveals significantly accelerated turnover rates across all taxonomic groups and ecosystems investigated, suggesting a common, anthropogenically induced driver of biodiversity change. Since these analyses most likely include DNA derived from dead as well as from living organisms, Chapter V aims to separate both groups by metabarcoding both DNA and less stable ribosomal RNA from mussel samples. Contrary to the hypothesis, RNA is detectable from both living endobionts and dietary taxa. However, it outcompetes DNA in detecting microeukaryotic biodiversity. In summary, this thesis demonstrates the outstanding potential of archived ESB samples for retrospective biodiversity monitoring, a resource that offers many further untapped opportunities for future biodiversity research at multiple scales.

A Framework for Multiobjective and Uncertain Resource Allocation Problems in Survey Sampling based on Conic Optimization (2025)

Willems, Felix

In most textbooks optimal sample allocation is tailored to rather theoretical examples. However, in practice we often face large-scale surveys with conflicting objectives and many restrictions on the quality and cost at population and subpopulation levels. This multiobjectiveness results in a multitude of efficient sample allocations, each giving different weight to a single survey purpose. Additionally, since the input data to the allocation problem often relies on supplementary information derived from estimation, historical data, or expert knowledge, allocations might be inefficient when specified for sampling. This doctoral thesis presents a framework for optimal allocation to standard sampling schemes that allows for specifying the tradeoff between different objectives and analyzing their sensitivity to other problem components, aiming to support a decision-maker in identifying an at-most preferred sample allocation. It dedicates a full chapter to each of the following core questions: 1) How to efficiently incorporate quality and cost constraints for large-scale surveys, say, for thousands of strata with hundreds of precision and cost constraints? 2) How to handle vector-valued objectives with their components addressing different, possibly conflicting survey purposes? 3) How to consider uncertainty in the input data? The techniques presented can be used separately or in combination as a general problem-solving framework for constrained multivariate and multidomain, possibly uncertain, sample allocation. The main problem is formulated in a way that highlights the different components of optimal sample allocation and can be taken as a gateway to develop solution strategies to each of the questions above, while shifting the focus between different problem aspects. The first question is addressed through a conic quadratic reformulation, which can be efficiently solved for large problem instances using interior-point methods. Based on this the second question is tackled using a weighted Chebyshev minimization, which provides insight into the sensitivity of the problem and enables a stepwise procedure for considering nonlinear decision functionals. Lastly, uncertainty in the input data is addressed through regularization, chance constraints and robust problem formulations.

Building on Social Virtual Reality to Support Flexible Collaboration and Enrich Therapy Sessions (2025)

Bimberg, Pauline

Social virtual environments allow their users to meet and collaborate in a shared three-dimensional space, even when far apart from each other in the real world. Within these spaces, the appearance and interaction capabilities of both users and environments can be adapted and changed in a myriad of ways. To enable virtual environments to fulfill their potential of supporting a wide variety of collaboration use-cases, both the impacts of basic interaction design decisions and the individual needs of specific usage areas need to be explored further. This thesis approaches this topic in two ways. First, the basic building blocks of collaboration in social virtual environments are explored by asking the question: "How can social virtual spaces that allow interaction beyond real-world constraints utilize the potential of mutual assistance and shared workflows between multiple users?". Going into further detail for a serious use-case in which direct collaborative interactions and their effect on the included users are especially important, it then explores the potential of collaborative virtual spaces in the therapy domain by asking "How can the potential of social virtual spaces be utilized to support and improve therapy encounters?" With regards to the first research question, the thesis presents two theoretical frameworks detailing different aspects of supporting smooth and varied collaboration processes. In addition, several user studies on the topic of collaborative virtual interaction are described, focusing on the role that different users can play during shared interaction and the effects that this distribution of roles and responsibilities has on both the performance and experience of the involved user pairs. The results presented for this first research question show that social virtual spaces have the potential to provide dedicated support for collaborative workflows. To enable users to adapt their working mode individually and as a team, interaction techniques should complement a team's natural interaction and communication. When presenting novel interactions to users, providing them with a way to support each other can ease their adaptation to these interactions. In these cases, the inclusion of all interested collaborators as active participators should be prioritized in order to let all users benefit from being immersed in a virtual environment. Addressing the combination of social virtual spaces with therapy in relation to the second research question, this thesis presents the result of a series of interviews with practicing physio- and psychotherapists. Motivated by the recorded expert feedback, it also reports on two more detailed explorations of specific areas of interest. The work presented for the second research question demonstrated the promise of using virtual environments in both exercise- and conversation-based therapy practice. Investigating the potential of shared interactions, the exploration of virtual recordings and the adaptation of virtual appearances, the presented work uncovered several topic areas that could be further explored regarding their possible use in the treatment of patients. Taken together, the six research articles presented in this thesis show both the value of supporting and understanding shared interactions in virtual spaces and their potential place in serious use-cases like the therapy domain. When introducing shared virtual environments to new user groups, the opportunity for mutual support through shared interaction techniques could be a crucial building block towards making virtual spaces both accessible and attractive to a variety of users.

Variable Stress Patterns in English Complex Adjectives: Inter-Individual Differences and the Nature of the Morphology-Phonology Interface (2025)

Ganster, Tammy

The present dissertation deals with variable stress patterns in English complex adjectives such as celebratory, identifiable or imaginative. This variation is usually described in terms of retaining the stress from the embedded base (idéntify -> idéntifiable) or deviating from the stress of the embedded base (idéntify -> identifíable). While several accounts have explored this variation, none of them have been able to identify a plausible reason for why it occurs. Additionally, the role of individual speaker differences has been disregarded in the discussion. This dissertation therefore explores the empirically observable extent of the variation and investigates possible causes of it with a special focus on individual differences between speakers. It uses data from a complex online experiment that included five different tasks to assess speakers' stress production, perception, morphological processing, vocabulary size and other factors. It furthermore tests the predictions of previous accounts on the large set of authentic utterances from speakers collected using this online experiment. The data show that individual differences in vocabulary size between speakers are a significant predictor of a speaker's tendency to retain the stress of the embedded base.

From Financial Stability to Digital Payments: Empirical Insights into Central Banking (2025)

Wischnewsky, Arina

The new millennium has been characterized by rising digitalization, the proliferation of shadow banking, and significant advancements in machine learning and natural language processing. These trends present both challenges and opportunities, which my dissertation addresses. This cumulative dissertation investigates critical aspects of financial stability, monetary policy, and the transition towards cashless economies through three distinct but interrelated studies. The first paper examines the risk-taking channel of monetary policy transmission within the euro area, focusing on shadow banks. Through vector autoregressive models, it assesses the impact of conventional and unconventional monetary policy shocks on shadow banks' asset growth and risk asset ratios. The results indicate that lower interest rates lead to a portfolio reallocation towards riskier assets and a general expansion of assets in shadow banks. In the case of conventional monetary policy shocks, both effects last three times as long as in the case of unconventional monetary policy shocks. Country-specific as well as sector-specific estimations confirm these findings. This study bridges gaps in the existing literature, especially in the eurozone, by highlighting the significant role shadow banks play in monetary policy transmission, suggesting implications for financial regulation and stability. The second paper explores the influence of financial stability considerations on US monetary policy, particularly during the Great Recession. Utilizing natural language processing and machine learning techniques on congressional hearings, this study constructs indicators for financial stability sentiment expressed by the Federal Reserve Chairs. Empirical analysis is conducted using Taylor-rule models, revealing that negative financial stability sentiment is associated with a more accommodative monetary policy stance, even before the Great Recession. This work provides new insights into the integration of financial stability concerns into monetary policy frameworks, demonstrating the need for a balanced approach to economic stability. The article suggests that under a dual mandate, such as that of the Federal Reserve, financial stability can, to some extent, already be factored into monetary policy deliberations. The third paper sheds new light on ``cash paradox'' by uncovering the factors of the cashless transition that has not been entirely understood so far. Using a comprehensive dataset across 65 countries, the study employs panel data models to explain the paradox (increasing demand for central bank money despite soaring digitalization), especially among technologically advanced countries, e.g., Japan. Empirical evidence suggests that digitalization is not significantly associated with higher reliance on physical cash. It uncovers a unique non-linear relationship between trust and cash usage (``Arch of Trust'') which holds after addressing potential endogeneity issues using 2SLS estimation. Opposed to the widespread misinterpretations of Keynes' (1937) reasons for holding cash, the findings highlight that distrust is the key factor unlocking two distinct puzzles in economics, linking cash hoarding with ``missing'' funds on capital markets and slower shift toward digital payments in low-trust societies. A key insight is the role of trust as a (social) insurance, cushion or safety net, dampening the perception of risk and reducing precautionary and transactionary demand for physical cash, while encouraging a shift towards riskier alternatives. This, in turn, is connected to the third puzzle, the ``paradox of prudence.'' A shift from riskier investments to safer assets, cash, may be prudent at the individual level but risky for the overall economy, a concern for macroprudential policymakers. Additionally, the research highlights the critical role of culture in driving the global movement towards cashless economies. Moreover, cultures that are more self-expression-oriented (which is the main cultural dimension) and culturally closer to Sweden are associated with less cash-intensive economies. These insights are vital for macroprudential regulators as well as for policymakers designing payment systems and CBDC in culturally diverse regions like the Eurozone. Collectively, these papers contribute to a deeper understanding of monetary policy, financial stability, and the transition from cash-based to (nearly) cashless societies, offering significant theoretical and practical implications for academics, regulators and central bankers.

Biodiversity in a bottle – metabarcoding environmental samples from long-term monitoring archives for retrospective assessment of changes in biotic communities in the Anthropocene (2025)

Hans, Julian

Biotic communities experienced significant changes in recent decades. Climate change, the overexploitation of natural resources and the immigration of invasive species are major drivers for this change and present unknown challenges for communities worldwide. To assess the impact of these drivers, standardised long-term studies are required, which are currently lacking for many species and ecosystems. Analysing environmental samples and the DNA of associated organisms using metabarcoding and high-throughput sequencing provides a cost-efficient and rapid way to generate the high-resolution biodiversity data which is so direly needed. In this thesis, I demonstrate the great potential of using samples from the German Environ- mental Specimen Bank (ESB), a long-term monitoring archive that has been collecting and cryogenically storing highly standardised environmental samples since 1985. Modern analytical methods enable retrospective long-term biodiversity monitoring using these samples. In the first chapter, I illustrate metabarcoding as a central method, discussing its strengths and drawbacks, how to avoid them, and new application approaches. This chapter provides the methodological basis for the following studies. In subsequent chapters, I present time series analyses of communities associated with these environmental samples. While for Chapter two the focus is on terrestrial arthropod communities, in Chapter three aquatic and terrestrial communities across the tree of life are analysed. A null model was developed for this survey for robust conclusions. The studies covered the last three decades and revealed substantial compositional changes across all ecosystems. These changes deviated significantly from the model, indicating that the changes are occurring faster than expected. Moreover, a trend toward homogenization in many terrestrial communities was uncovered. Climate change and the immigration of invasive species in combination with the loss of site-specific species are suspected to be the main drivers for this. In a follow-up study, changes of arthropod communities in German and South Korean terrestrial ecosystems were compared using ESB leaf samples from these two countries. Since both ESBs are harmonised in sample collection and processing, comparative analyses were applicable. This research covered the last decade and revealed substantial declines in species richness in Korea. Abiotic and biotic factors are discussed as potential drivers of these results. Finally, the possibility of assessing tree health by analysing changes in functional fungal groups using German ESB samples was investigated. The results indicate that increasing infestation of specific functional groups is a proxy for declining tree health, with further analyses planned. In this dissertation, I present the great potential of samples from long-term monitoring archives to conduct retrospective biodiversity trend analyses across the tree of life. As technologies evolve, these samples will help to understand past and predict future ecosystem changes.

The prosodic marking of rhetorical questions in Standard Chinese (2022)

Zahner-Ritter, Katharina ; Chen, Yiya ; Dehé, Nicole ; Braun, Bettina

The present study investigates the prosody of information-seeking (ISQs) and rhetorical questions (RQs) in Standard Chinese, in polar and wh-questions. Like in other languages, ISQs and RQs in Standard Chinese can have the same surface structure, allowing for a direct prosodic comparison between illocution types (ISQ vs RQ). Since Standard Chinese has lexical tone, the use of f0 as a cue to illocution type may be restricted. We investigate the prosodic differences between ISQs and RQs as well as the interplay of prosodic cues to RQs. In terms of f0, results showed that RQs were lower in f0, with the f0 range on the first word being expanded followed by f0 compression. RQs were further longer in duration and more often realized with non-modal voice quality (glottalized voice) as compared to ISQs. These prosodic cues were largely manipulated in tandem (illocutionary pairs with larger durational differences also showed larger differences in mean f0; voice quality, in turn, seemed to be an additional cue). We suggest three possible explanations (assertive force, focus, speaker attitude) that unite the present findings on RQs in Standard Chinese with the findings on RQs in other, non-tonal languages.

Individual and contextual predictors of the entrepreneurial process - A multi-level perspective on the behavior of entrepreneurs and self-employed (2025)

Gnad, Miriam

Entrepreneurship is recognized as an important discipline to achieve sustainable development and to address sustainability goals without losing sight of economic aspects. However, entrepreneurship rates are rather low in many industrialized countries with high income levels. Research clearly shows that there is a gap in the entrepreneurial process between intentions and subsequent actions. This means that not everyone with entrepreneurial ambitions also follows through and implements actions. This gap also exists for aspects of sustainability. As a result, there is a need to better understand the traditional and sustainability-focused entrepreneurial process in order to increase corresponding actions. This dissertation offers such a comprehensive perspective and sheds light on individual and contextual predictors for traditional and sustainability-focused behavior of entrepreneurs and self-employed across four studies. The first three studies focus on individual predictors. By providing a systematic literature review with 107 articles, Chapter 2 highlights the ambivalent role of religion for the entrepreneurial process. Relying on the theory of planned behavior (TPB) as theoretical basis, religion can have positive effects on entrepreneurial attitudes and behavioral control, but also negative consequences for other aspects of behavioral control and subjective norms due to religious restrictions. The quantitative empirical study in Chapter 3 similarly relies on the TPB and sheds light on individual perceptual factors influencing the sustainability-related intention-action gap in entrepreneurship. Using data from the 2021 Global Entrepreneurship Monitor (GEM) Adult Population Survey (APS) including 22,008 early-stage entrepreneurs from 44 countries worldwide, the results support our theoretical reasoning that sustainability-focused intentions are positively related to social entrepreneurial actions. In addition, it is demonstrated that positive perceptual moderators such as self-efficacy and knowing other entrepreneurs as role models strengthen this relationship while a negative perception such as fear of failure restricts social actions in early-stage entrepreneurship. The next quantitative empirical study in Chapter 4 examines the behavioral consequences of well-being at a sample of 6,955 German self-employed during COVID-19. This chapter builds on two complementary behavioral perspectives to predict how reductions in financial and non-financial well-being relate to investments in venture development. In this regard, reductions in financial well-being are positively related to time investments, supporting the performance feedback perspective in terms of higher search efforts under negative performance. In contrast, reductions in non-financial well-being are negatively related to time and monetary investments, yielding support for the broadening-and-build perspective indicating that negative psychological experiences narrow the thought-action repertoire and hinder resource deployment. The insights across these first three studies about individual predictors indicate that many different, subjective beliefs, perceptions and emotional states can influence the entrepreneurial process making entrepreneurship and self-employment highly individualized disciplines. The last quantitative empirical study provides an explorative view on a large number of contextual predictors for social and ecological considerations in entrepreneurial actions. Combining GEM data from 2021 on country level with further information from the World Bank and the OECD, a machine learning approach is employed on a sample of 84 countries worldwide. The results suggest that governmental and regulatory as well as cultural factors are relevant to predict social and ecological considerations. Moreover, market-related aspects are shown to be relevant predictors, especially socio-economic factors for social considerations and economic factors for ecological considerations. Overall, the four studies in this dissertation highlight the complexity of the entrepreneurial process being determined by many different individual and contextual factors. Due to the multitude of potential predictors, this dissertation can only give an initial overview of a selection of factors with many more aspects and interdependencies still to be examined by future research.

The Airline Industry: Risk Management and CO2 Emissions (2025)

Flick, Annika

Within this thesis the hedging behaviour of airlines from 2005 to 2019 is analysed by using an unbalanced panel dataset consisting of a total of 78 airlines from 39 countries. The focus of the analysis is on financial and operational hedging as well as the influence of both on CO2 emissions and the development of emitted CO2 emissions. For the analysis Probit models with random effects and OLS models with fixed effects were used. The results regarding the relationship between leverage and financial hedging indicate a negative relationship between everage and financial fuel hedging and a non-linear convex relationship for highly leveraged airlines, which is contrary to the theory of financial distress. In addition, the study provides evidence that airlines using other types of derivatives, such as interest rate derivatives, engage in more fuel hedging. In terms of operational hedging, the analysis suggests that operating a diversified fleet is a complement to, rather than a substitute for, financial hedging. With regard to alliance membership, the results do not show that alliance membership is a substitute for financial hedging, as members of alliances are more likely to engage in hedging transactions and to a greater extent. The analysis shows that the relative CO2 emissions fall in the period under review, but this does not apply to the absolute amount. No general statement can be made about the influence of financial and operational hedging on CO2 emissions, as the results are mixed.

Boundary Value Problem Governed by Symmetric Nonlocal Operators (2025)

Huschens, Julia

When natural phenomena and data-based relations are driven by dynamics which are not purely local, they cannot be described satisfactorily by partial differential equations. As a consequence, mathematical models governed by nonlocal operators are of interest. This thesis is concerned with nonlocal operators of the form $\mathcal{L}u(x) = PV \int_{\mathbb{R}^d} (u(x)-u(y)) K(x,dy), x \in \mathbb{R}^d$, which are determined through a family of Borel measures $K=(K(x, \cdot))_{x \in \mathbb{R}^d}$ on $\mathbb{R}^d$ and which act on the vector space of Borel measurable functions $u: \mathbb{R}^d \rightarrow \mathbb{R}$. For a large class of families $K$, namely those where $K$ is a symmetric transition kernel satisfying a specific non-degeneracy condition, a variational theory for nonlocal equations of the type $\mathcal{L}u=f$ is established which builds upon gadgets from both measure theory and classical analysis. While measure theory is used to provide a nonlocal integration by parts formula that allows to set up a reasonable variational formulation of the above equation in dependency of the particular boundary condition (Dirichlet, Robin, Neumann) considered, Hilbert space theory and fixed-point approaches are utilized to develop sufficient conditions for the existence of variational solutions. This theory is then applied to two specific realizations of $\mathcal{L}$ of interest before a weak maximum principle is established which is finally used to study overlapping domain decomposition methods for the nonlocal and homogeneous Dirichlet problem.

The Role of Private Debt as an Alternative Form of Financing (2025)

Schulze, Anna

Small and medium-sized enterprises (SMEs) and mid-sized companies are vital contributors to the global economy, driving employment growth, fostering innovation, and enhancing international competiveness. However, in the aftermath of the Great Financial Crisis (GFC) and the collapse of the large finance company CIT Group, which provided 60% loans to US middle-market firms, banks reduced their lending activities. Thus, it became challenging for firms to obtain long-term loans. The financing gap has increased further due to high interest rates, the COVID-19 pandemic, the unstable situation in the real estate market as well as higher costs due to the adoption of digital infrastructure and sustainability goals. Therefore, the search for alternative financing solutions outside bank lending and public markets became unavoidable for SMEs and mid-sized companies. Private debt funds entered the market, and, since the GFC, they have played a crucial role in offering alternative financing for firms globally. Private debt fund managers raise capital commitments through closed-end funds (like private equity) and make senior loans (like banks) directly to, mostly, middlemarket firms. The private debt market has experienced rapid growth in recent decades. The private debt funds assets under management (AuM) increased by 380% from 2008 to 2022, reaching $1.5 trillion AuM in 2022 . The high growth of private debt shows great interest from investors in this alternative asset class and lucrative investment opportunities. Despite its substantial and growing size, the private debt market is relatively understudied. This dissertation introduces private debt as an important alternative financing source, provides an overview of private debt strategies, seniority, and structure, discusses the legal considerations concerning private debt, and briefly compares the two most mature private debt markets: Europe and the U.S. Moreover, it assesses the size of the European private debt market and compares its development in different European regions. Furthermore, it examines in detail the business model of private debt funds based on a survey of 191 European and U.S. private debt managers with private debt assets under management of over $390 billion. Finally, it delves deeper into the relationship between private debt and private equity funds and their role in buyouts. To sum up, this dissertation provides a basis and inspiration for future research to expand upon and dive deeper into the world of private debt funds, their business model, and their impact on portfolio companies and the economy as a whole.

Hybrid AI for Process Management - Improving Similarity Assessment in Process-Oriented Case-Based Reasoning via Deep Learning (2025)

Hoffmann, Maximilian

Case-Based Reasoning (CBR) is a symbolic Artificial Intelligence (AI) approach that has been successfully applied across various domains, including medical diagnosis, product configuration, and customer support, to solve problems based on experiential knowledge and analogy. A key aspect of CBR is its problem-solving procedure, where new solutions are created by referencing similar experiences, which makes CBR explainable and effective even with small amounts of data. However, one of the most significant challenges in CBR lies in defining and computing meaningful similarities between new and past problems, which heavily relies on domain-specific knowledge. This knowledge, typically only available through human experts, must be manually acquired, leading to what is commonly known as the knowledge-acquisition bottleneck. One way to mitigate the knowledge-acquisition bottleneck is through a hybrid approach that combines the symbolic reasoning strengths of CBR with the learning capabilities of Deep Learning (DL), a sub-symbolic AI method. DL, which utilizes deep neural networks, has gained immense popularity due to its ability to automatically learn from raw data to solve complex AI problems such as object detection, question answering, and machine translation. While DL minimizes manual knowledge acquisition by automatically training models from data, it comes with its own limitations, such as requiring large datasets, and being difficult to explain, often functioning as a "black box". By bringing together the symbolic nature of CBR and the data-driven learning abilities of DL, a neuro-symbolic, hybrid AI approach can potentially overcome the limitations of both methods, resulting in systems that are both explainable and capable of learning from data. The focus of this thesis is on integrating DL into the core task of similarity assessment within CBR, specifically in the domain of process management. Processes are fundamental to numerous industries and sectors, with process management techniques, particularly Business Process Management (BPM), being widely applied to optimize organizational workflows. Process-Oriented Case-Based Reasoning (POCBR) extends traditional CBR to handle procedural data, enabling applications such as adaptive manufacturing, where past processes are analyzed to find alternative solutions when problems arise. However, applying CBR to process management introduces additional complexity, as procedural cases are typically represented as semantically annotated graphs, increasing the knowledge-acquisition effort for both case modeling and similarity assessment. The key contributions of this thesis are as follows: It presents a method for preparing procedural cases, represented as semantic graphs, to be used as input for neural networks. Handling such complex, structured data represents a significant challenge, particularly given the scarcity of available process data in most organizations. To overcome the issue of data scarcity, the thesis proposes data augmentation techniques to artificially expand the process datasets, enabling more effective training of DL models. Moreover, it explores several deep learning architectures and training setups for learning similarity measures between procedural cases in POCBR applications. This includes the use of experience-based Hyperparameter Optimization (HPO) methods to fine-tune the deep learning models. Additionally, the thesis addresses the computational challenges posed by graph-based similarity assessments in CBR. The traditional method of determining similarity through subgraph isomorphism checks, which compare nodes and edges across graphs, is computationally expensive. To alleviate this issue, the hybrid approach seeks to use DL models to approximate these similarity calculations more efficiently, thus reducing the computational complexity involved in graph matching. The experimental evaluations of the corresponding contributions provide consistent results that indicate the benefits of using DL-based similarity measures and case retrieval methods in POCBR applications. The comparison with existing methods, e.g., based on subgraph isomorphism, shows several advantages but also some disadvantages of the compared methods. In summary, the methods and contributions outlined in this work enable more efficient and robust applications of hybrid CBR and DL in process management applications.

Linking Microsimulation and Macroeconomic Models for Labor Market Analyses (2025)

Dieckmann, Hanna

There is a wide range of methodologies for policy evaluation and socio-economic impact assessment. A fundamental distinction can be made between micro and macro approaches. In contrast to micro models, which focus on the micro-unit, macro models are used to analyze aggregate variables. The ability of microsimulation models to capture interactions occurring at the micro-level makes them particularly suitable for modeling complex real-world phenomena. The inclusion of a behavioral component into microsimulation models provides a framework for assessing the behavioral effects of policy changes. The labor market is a primary area of interest for both economists and policy makers. The projection of labor-related variables is particularly important for assessing economic and social development needs, as it provides insight into the potential trajectory of these variables and can be used to design effective policy responses. As a result, the analysis of labor market behavior is a primary area of application for behavioral microsimulation models. Behavioral microsimulation models allow for the study of second-round effects, including changes in hours worked and participation rates resulting from policy reforms. It is important to note, however, that most microsimulation models do not consider the demand side of the labor market. The combination of micro and macro models offers a possible solution as it constitutes a promising way to integrate the strengths of both models. Of particular relevance is the combination of microsimulation models with general equilibrium models, especially computable general equilibrium (CGE) models. CGE models are classified as structural macroeconomic models, which are defined by their basis in economic theory. Another important category of macroeconomic models are time series models. This thesis examines the potential for linking micro and macro models. The different types of microsimulation models are presented, with special emphasis on discrete-time dynamic microsimulation models. The concept of behavioral microsimulation is introduced to demonstrate the integration of a behavioral element into microsimulation models. For this reason, the concept of utility is introduced and the random utility approach is described in detail. In addition, a brief overview of macro models is given with a focus on general equilibrium models and time series models. Various approaches for linking micro and macro models, which can either be categorized as sequential approaches or integrated approaches, are presented. Furthermore, the concept of link variables is introduced, which play a central role in combining both models. The focus is on the most complex sequential approach, i.e., the bi-directional linking of behavioral microsimulation models with general equilibrium macro models.

Comparing Operators Acting on Different Hilbert Spaces (2025)

Zimmer, Sebastian

The goal of this work is to compare operators that are defined on probably varying Hilbert spaces. Distance concepts for operators as well as convergence concepts for such operators are explained and examined. For distance concepts we present three main notions. All have in common that they use space-linking operators that connect the spaces. At first, we look at unitary maps and compare the unitary orbits of the operators. Then, we consider isometric embeddings, which is based on a concept of Joachim Weidmann. Then we look at contractions but with more norm equations in comparison. The latter idea is based on a concept of Olaf Post called quasi-unitary equivalence. Our main result is that the unitary and isometric distances are equal provided the operators are both self-adjoint and have 0 in their essential spectra. In the third chapter, we focus specifically on the investigation of these distance terms for compact operators or operators in p-Schatten classes. In this case, the interpretation of the spectra as null sequences allows further distance investigation. Chapter four deals mainly with convergence terms of operators on varying Hilbert spaces. The analyses in this work deal exclusively with concepts of norm resolvent convergence. The main conclusion of the chapter is that the generalisation for norm resolvent convergence of Joachim Weidmann and the generalisation of Olaf Post, called quasi-unitary equivalence, are equivalent to each other. In addition, we specify error bounds and deal with the convergence speed of both concepts. Two important implications of these convergence notions are that the approximation is spectrally exact, i.e., the spectra converge suitably, and that the convergence is transferred to the functional calculus of the bounded functions vanishing at infinity.

Large Players, Information and Coordination (2025)

Specovius, Jan

In this dissertation, I analyze how large players in financial markets exert influence on smaller players and how this affects the decisions of the large ones. I focus on how the large players process information in an uncertain environment, form expectations and communicate these to smaller players through their actions. I examine these relationships empirically in the foreign exchange market and in the context of a game-theoretic model of an investment project. In Chapter 2, I investigate the relationship between the foreign exchange trading activity of large US-based market participants and the volatility of the nominal spot exchange rate. Using a novel dataset, I utilize the weekly growth rate of aggregate foreign currency positions of major market participants to proxy trading activity in the foreign exchange market. By estimating the heterogeneous autoregressive model of realized volatility (HAR-RV), I find evidence of a positive relationship between trading activity and volatility, which is mainly driven by unexpected changes in trading activity and is asymmetric for some of the currencies considered. My results contribute to the understanding of the drivers of exchange rate volatility and the role of large players in the flow of information in financial markets. In Chapters 3 and 4, I consider a sequential global game of an investment project to examine how a large creditor influences the decisions of small creditors with her lending decision. I pay particular attention to the timing of the large player’s decision, i.e. whether she makes her decision to roll over a credit before or after the small players. I show that she faces a trade-off between signaling to and learning from small creditors. By being a focal point for coordination, her actions have a substantial impact on the probability of coordination failure and the failure of the investment project. I investigate the sensitivity of the equilibrium by comparing settings with perfect and imperfect learning. The results highlight the importance of signaling and provide a new perspective on the idea of catalytic finance and the influence of a lender-of-last-resort in self-fulfilling debt crises.

Catchment Properties Shape Seasonal Variation in Groundwater-Surface Water Interaction—Geogenic Silica as a Proxy for Hydrological Turnover Induced Mixing (2024)

Bäthke, Lars ; Schuetz, Tobias

The cumulative and bidirectional groundwater-surface water (GW-SW) interaction along a stream is defined as hydrological turnover (HT) influencing solute transport and source water composition. However, HT proves to be highly variable, producing spatial exchange patterns influenced by local groundwater, geology, and topography. Hence, identifying factors controlling HT poses a challenge. We studied spatiotemporal HT variability at two reaches of a third order tributary of the river Mosel, Germany. Additionally, we sampled for silica concentrations in the stream and in the near-stream groundwater. Thus, creating snapshots of the boundary layer between ground- and surface water where HT occurs, driven by mixing processes in the hyporheic zone. We utilize an enhanced hydrograph separation method, unveiling reach differences in storage drainage based on aquifer dimension and connectivity. The data shows a site-specific negative correlation of HT with discharge, while hydraulic gradients correlate with HT only at the reach with faster catchment drainage behavior. Examining silica concentrations between stream and wells shows that silica variation increases significantly with the decrease of HT under low flow conditions at the slower draining reach. At the fast draining reach this relationship is seasonal. In Summary, our results show that stream discharge shapes the influence of HT on solute transport. Yet, reach drainage behavior shapes seasonal states of groundwater storages and can be an additional control of HT. Hence, concentration change of pollutants could be masked by HT. Thus, our findings contribute to the understanding of HT variability along streams and its ability of influencing physico-chemical stream water composition.

Homophobia in Greece - Contact-Mediated Effects of Demographics and Political and Religious Orientation (2025)

Hindenlang, Fabian ; Kranz, Dirk ; Chourdaki, Maria ; Koupa, Melodia

Introduction: Apart from a few studies with limited sample sizes, we have little data on attitudes toward lesbian and gay (LG) people in Greece. Methods: This study examines this topic in 949 heterosexual Greek participants. Based on previous research in cultural contexts other than Greece, we hypothesized that four demographics (gender, age, education, area of residence) and religious and political orientation predict a substantial amount of variance in homophobia (i.e., anti-LG attitudes). Results: We verified all observed variables except area of residence as significant predictors. Regarding the “intergroup contact hypothesis,” we distinguished the direct effects of the predictor variables from indirect effects mediated by contact with lesbians and gay men. All variables except area of residence showed a direct effect and, except for education, also an indirect effect on homophobia. The strongest effects were found for religious and political orientation, followed by gender. Highly religious, right-wing oriented, and male participants reported the highest levels of homophobia, partially mediated by their low level of contact with LG people. Discussion/Conclusion: The results confirm and further explain the detrimental role the Greek Orthodox Church, right-wing political parties, and traditional gender roles play in the acceptance of sexual minorities.

Exploring Biases of Large Language Models in the Field of Mental Health: Comparative Questionnaire Study of the Effect of Gender and Sexual Orientation in Anorexia Nervosa and Bulimia Nervosa Case Vignettes (2025)

Schnepper, Rebekka ; Roemmel, Noa ; Schaefert, Rainer ; Lambrecht-Walzinger, Lena ; Meinlschmidt, Gunther

Background: Large language models (LLMs) are increasingly used in mental health, showing promise in assessing disorders. However, concerns exist regarding their accuracy, reliability, and fairness. Societal biases and underrepresentation of certain populations may impact LLMs. Because LLMs are already used for clinical practice, including decision support, it is important to investigate potential biases to ensure a responsible use of LLMs. Anorexia nervosa (AN) and bulimia nervosa (BN) show a lifetime prevalence of 1%-2%, affecting more women than men. Among men, homosexual men face a higher risk of eating disorders (EDs) than heterosexual men. However, men are underrepresented in ED research, and studies on gender, sexual orientation, and their impact on AN and BN prevalence, symptoms, and treatment outcomes remain limited. Objectives: We aimed to estimate the presence and size of bias related to gender and sexual orientation produced by a common LLM as well as a smaller LLM specifically trained for mental health analyses, exemplified in the context of ED symptomatology and health-related quality of life (HRQoL) of patients with AN or BN. Methods: We extracted 30 case vignettes (22 AN and 8 BN) from scientific papers. We adapted each vignette to create 4 versions, describing a female versus male patient living with their female versus male partner (2 × 2 design), yielding 120 vignettes. We then fed each vignette into ChatGPT-4 and to “MentaLLaMA” based on the Large Language Model Meta AI (LLaMA) architecture thrice with the instruction to evaluate them by providing responses to 2 psychometric instruments, the RAND-36 questionnaire assessing HRQoL and the eating disorder examination questionnaire. With the resulting LLM-generated scores, we calculated multilevel models with a random intercept for gender and sexual orientation (accounting for within-vignette variance), nested in vignettes (accounting for between-vignette variance). Results: In ChatGPT-4, the multilevel model with 360 observations indicated a significant association with gender for the RAND-36 mental composite summary (conditional means: 12.8 for male and 15.1 for female cases; 95% CI of the effect –6.15 to -0.35; P=.04) but neither with sexual orientation (P=.71) nor with an interaction effect (P=.37). We found no indications for main effects of gender (conditional means: 5.65 for male and 5.61 for female cases; 95% CI –0.10 to 0.14; P=.88), sexual orientation (conditional means: 5.63 for heterosexual and 5.62 for homosexual cases; 95% CI –0.14 to 0.09; P=.67), or for an interaction effect (P=.61, 95% CI –0.11 to 0.19) for the eating disorder examination questionnaire overall score (conditional means 5.59-5.65 95% CIs 5.45 to 5.7). MentaLLaMA did not yield reliable results. Conclusions: LLM-generated mental HRQoL estimates for AN and BN case vignettes may be biased by gender, with male cases scoring lower despite no real-world evidence supporting this pattern. This highlights the risk of bias in generative artificial intelligence in the field of mental health. Understanding and mitigating biases related to gender and other factors, such as ethnicity, and socioeconomic status are crucial for responsible use in diagnostics and treatment recommendations.

An Explainable Artificial Intelligence Text Classifier for Suicidality Prediction in Youth Crisis Text Line Users: Development and Validation Study (2025)

Thomas, Julia ; Lucht, Antonia ; Segler, Jacob ; Wundrack, Richard ; Miché, Marcel ; Lieb, Roselind ; Kuchinke, Lars ; Meinlschmidt, Gunther

Background: Suicide represents a critical public health concern, and machine learning (ML) models offer the potential for identifying at-risk individuals. Recent studies using benchmark datasets and real-world social media data have demonstrated the capability of pretrained large language models in predicting suicidal ideation and behaviors (SIB) in speech and text. Objective: This study aimed to (1) develop and implement ML methods for predicting SIBs in a real-world crisis helpline dataset, using transformer-based pretrained models as a foundation; (2) evaluate, cross-validate, and benchmark the model against traditional text classification approaches; and (3) train an explainable model to highlight relevant risk-associated features. Methods: We analyzed chat protocols from adolescents and young adults (aged 14-25 years) seeking assistance from a German crisis helpline. An ML model was developed using a transformer-based language model architecture with pretrained weights and long short-term memory layers. The model predicted suicidal ideation (SI) and advanced suicidal engagement (ASE), as indicated by composite Columbia-Suicide Severity Rating Scale scores. We compared model performance against a classical word-vector-based ML model. We subsequently computed discrimination, calibration, clinical utility, and explainability information using a Shapley Additive Explanations value-based post hoc estimation model. Results: The dataset comprised 1348 help-seeking encounters (1011 for training and 337 for testing). The transformer-based classifier achieved a macroaveraged area under the curve (AUC) receiver operating characteristic (ROC) of 0.89 (95% CI 0.81-0.91) and an overall accuracy of 0.79 (95% CI 0.73-0.99). This performance surpassed the word-vector-based baseline model (AUC-ROC=0.77, 95% CI 0.64-0.90; accuracy=0.61, 95% CI 0.61-0.80). The transformer model demonstrated excellent prediction for nonsuicidal sessions (AUC-ROC=0.96, 95% CI 0.96-0.99) and good prediction for SI and ASE, with AUC-ROCs of 0.85 (95% CI 0.97-0.86) and 0.87 (95% CI 0.81-0.88), respectively. The Brier Skill Score indicated a 44% improvement in classification performance over the baseline model. The Shapley Additive Explanations model identified language features predictive of SIBs, including self-reference, negation, expressions of low self-esteem, and absolutist language. Conclusions: Neural networks using large language model–based transfer learning can accurately identify SI and ASE. The post hoc explainer model revealed language features associated with SI and ASE. Such models may potentially support clinical decision-making in suicide prevention services. Future research should explore multimodal input features and temporal aspects of suicide risk.

Comparing Digital Versus Face-to-Face Delivery of Systemic Psychotherapy Interventions: Systematic Review and Meta-Analysis of Randomized Controlled Trials (2025)

Erasmus, Pieter ; Borrmann, Moritz ; Becker, Jule ; Kuchinke, Lars ; Meinlschmidt, Gunther

Background: As digital mental health delivery becomes increasingly prominent, a solid evidence base regarding its efficacy is needed. Objective: This study aims to synthesize evidence on the comparative efficacy of systemic psychotherapy interventions provided via digital versus face-to-face delivery modalities. Methods: We followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for searching PubMed, Embase, Cochrane CENTRAL, CINAHL, PsycINFO, and PSYNDEX and conducting a systematic review and meta-analysis. We included randomized controlled trials comparing mental, behavioral, and somatic outcomes of systemic psychotherapy interventions using self- and therapist-guided digital versus face-to-face delivery modalities. The risk of bias was assessed with the revised Cochrane Risk of Bias tool for randomized trials. Where appropriate, we calculated standardized mean differences and risk ratios. We calculated separate mean differences for nonaggregated analysis. Results: We screened 3633 references and included 12 articles reporting on 4 trials (N=754). Participants were youths with poor diabetic control, traumatic brain injuries, increased risk behavior likelihood, and parents of youths with anorexia nervosa. A total of 56 outcomes were identified. Two trials provided digital intervention delivery via videoconferencing: one via an interactive graphic interface and one via a web-based program. In total, 23% (14/60) of risk of bias judgments were high risk, 42% (25/60) were some concerns, and 35% (21/60) were low risk. Due to heterogeneity in the data, meta-analysis was deemed inappropriate for 96% (54/56) of outcomes, which were interpreted qualitatively instead. Nonaggregated analyses of mean differences and CIs between delivery modalities yielded mixed results, with superiority of the digital delivery modality for 18% (10/56) of outcomes, superiority of the face-to-face delivery modality for 5% (3/56) of outcomes, equivalence between delivery modalities for 2% (1/56) of outcomes, and neither superiority of one modality nor equivalence between modalities for 75% (42/56) of outcomes. Consequently, for most outcome measures, no indication of superiority or equivalence regarding the relative efficacy of either delivery modality can be made at this stage. We further meta-analytically compared digital versus face-to-face delivery modalities for attrition (risk ratio 1.03, 95% CI 0.52-2.03; P=.93) and number of sessions attended (standardized mean difference –0.11; 95% CI –1.13 to –0.91; P=.83), finding no significant differences between modalities, while CIs falling outside the range of the minimal important difference indicate that equivalence cannot be determined at this stage. Conclusions: Evidence on digital and face-to-face modalities for systemic psychotherapy interventions is largely heterogeneous, limiting conclusions regarding the differential efficacy of digital and face-to-face delivery. Nonaggregated and meta-analytic analyses did not indicate the superiority of either delivery condition. More research is needed to conclude if digital and face-to-face delivery modalities are generally equivalent or if—and in which contexts—one modality is superior to another.

Integration of Conventional and Virtual Reality Approaches in Augmented Reality for Theory-Based Psychoeducational Intervention Design for Chronic Low Back Pain: Scoping Review (2025)

Conen, Robin ; Mueller, Steffen ; Tibubos, Ana Nanette

Background: Psychoeducation positively influences the psychological components of chronic low back pain (CLBP) in conventional treatments. The digitalization of health care has led to the discussion of virtual reality (VR) interventions. However, CLBP treatments in VR have some limitations due to full immersion. In comparison, augmented reality (AR) supplements the real world with virtual elements involving one’s own body sensory perception and can combine conventional and VR approaches. Objective: The aim of this study was to review the state of research on the treatment of CLBP through psychoeducation, including immersive technologies, and to formulate suggestions for psychoeducation in AR for CLBP. Methods: A scoping review following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was performed in August 2024 by using Livivo ZB MED, PubMed, Web of Science, American Psychological Association PsycINFO (PsycArticle), and PsyArXiv Preprints databases. A qualitative content analysis of the included studies was conducted based on 4 deductively extracted categories. Results: We included 12 studies published between 2019 and 2024 referring to conventional and VR-based psychoeducation for CLBP treatment, but no study referred to AR. In these studies, educational programs were combined with physiotherapy, encompassing content on pain biology, psychological education, coping strategies, and relaxation techniques. The key outcomes were pain intensity, kinesiophobia, pain catastrophizing, degree of disability, quality of life, well-being, self-efficacy, depression, attrition rate, and user experience. Passive, active, and gamified strategies were used to promote intrinsic motivation from a psychological point of view. Regarding user experience from a software development perspective, user friendliness, operational support, and application challenges were recommended.

Digital leadership in meta-organizations? Emergence of a renewed relevance of leadership in the context of digitization (2024)

Freis, Tamara ; Schröer, Andreas

In the face of uncontrollable complexity, the concept of a rational design of the organization is being replaced by the notion of an open future that is inherently unpredictable and unplanable. In rapidly changing environments, organizations and leaders are confronted with a constant stream of irritations and unexpected developments, that require ongoing attention. This prompts the question of whether the conceptualization of digital transformation as a paradigm shift also implies the need for new forms of leadership. The article analyzes the discourse on digital leadership and assesses the extent to which this concept relativizes leadership in the context of the evolution of leadership theory, which is characterized by a persistent process of modification and relativization of preceding concepts. Leadership concepts are not only responsive to general needs, but also vary according to specific contexts, such as non-profit leadership or leadership in social welfare organizations and meta-organizations. Results of a discourse analysis, which underscore the significance of adopting a complexity theory perspective on digital leadership, will therefore be contrasted with the initial findings of an empirical study on digitization in such meta-organizations. This allows for a discussion of the general findings on the revitalization of leadership, which will serve as a paradigmatic example of the previously developed context. The article concludes with implications for further theory development with the aim of making a specific contribution to organization-sensitive digitization research. The findings of the empirical study indicate the significance of employing informal structures and a heightened emphasis on subjectivity within meta-organizations, as opposed to the formal structures of organizations. The concept of digital leadership does not signify the obsolescence of traditional leadership; rather, it can be conceptualized as an advanced form of unheroic leadership within the context of external and internal complexity.

Crystallized Intelligence, Fluid Intelligence, and Need for Cognition: Their Longitudinal Relations in Adolescence (2024)

Scherrer, Vsevolod ; Breit, Moritz ; Preckel, Franzis

Investment theory and related theoretical approaches suggest a dynamic interplay between crystallized intelligence, fluid intelligence, and investment traits like need for cognition. Although cross-sectional studies have found positive correlations between these constructs, longitudinal research testing all of their relations over time is scarce. In our pre-registered longitudinal study, we examined whether initial levels of crystallized intelligence, fluid intelligence, and need for cognition predicted changes in each other. We analyzed data from 341 German students in grades 7–9 who were assessed twice, one year apart. Using multi-process latent change score models, we found that changes in fluid intelligence were positively predicted by prior need for cognition, and changes in need for cognition were positively predicted by prior fluid intelligence. Changes in crystallized intelligence were not significantly predicted by prior Gf, prior NFC, or their interaction, contrary to theoretical assumptions. This pattern of results was largely replicated in a model including all constructs simultaneously. Our findings support the notion that intelligence and investment traits, particularly need for cognition, positively interact during cognitive development, but this interplay was unexpectedly limited to Gf.

Gaze behavior in response to affect during natural social interactions (2024)

Vehlen, Antonia ; Belopolsky, Artem V. ; Domes, Gregor

Attention in social interactions is directed by social cues such as the face or eye region of an interaction partner. Several factors that influence these attentional biases have been identified in the past. However, most findings are based on paradigms with static stimuli and no interaction potential. Therefore, the current study investigated the influence of one of these factors, namely facial affect in natural social interactions using an evaluated eye-tracking setup. In a sample of 35 female participants, we examined how individuals’ gaze behavior responds to changes in the facial affect of an interaction partner trained in affect modulation. Our goal was to analyze the effects on attention to facial features and to investigate their temporal dynamics in a natural social interaction. The study results, obtained from both aggregated and dynamic analyses, indicate that facial affect has only subtle influences on gaze behavior during social interactions. In a sample with high measurement precision, these findings highlight the difficulties of capturing the subtleties of social attention in more naturalistic settings. The methodology used in this study serves as a foundation for future research on social attention differences in more ecologically valid scenarios.

Up for the challenge: Power motive congruence drives nurses to craft their jobs and experience well-being (2024)

Ghazzawi, Rawan ; Chasiotis, Athanasios ; Bender, Michael ; Daouk‐Öyry, Lina ; Baumann, Nicola

Job crafting is the behavior that employees engage in to create personally better fitting work environments, for example, by increasing challenging job demands. To better understand the driving forces behind employees’ engagement in job crafting, we investigated implicit and explicit power motives. While implicit motives tend to operate at the unconscious, explicit motives operate at the unconscious level. We focused on power motives, as power is an agentic motive characterized by the need to influence your environment. Although power is relevant to job crafting in its entirety, in this study, we link it to increasing challenging job demands due to its relevance to job control, which falls under the umbrella of power. Using a cross-sectional design, we collected survey data from a sample of Lebanese nurses (N = 360) working in 18 different hospitals across the country. In both implicit and explicit power motive measures, we focused on integrative power that enable people to stay calm and integrate opposition. The results showed that explicit power predicted job crafting (H1) and that implicit power amplified this effect (H2). Furthermore, job crafting mediated the relationship between congruently high power motives and positive work-related outcomes (H3) that were interrelated (H4). Our findings unravel the driving forces behind one of the most important dimensions of job crafting and extend the benefits of motive congruence to work-related outcomes.

1 to 100

Refine

Author

Year of publication

Document Type

Language

Has Fulltext

Keywords

Institute

660 search hits