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The spatial dimension of innovation and socio-technical change: insights from economic geography
(2026) Losacker, Sebastian
This habilitation thesis explores the spatial dimension of innovation and socio-technical change. While innovation is a key driver of economic development and socio-technical transformation, its geographical embeddedness remains insufficiently understood. The thesis addresses this gap by examining the origins, situatedness, and implications of innovation processes, with particular attention to the bioeconomy and the twin transition – domains of high political and societal relevance. The thesis is a cumulative one, combining 21 published articles. The theoretical foundation of this thesis draws on (and contributes to) three main strands of scholarship: First, literature on the geography of innovation, including frameworks for analyzing national, regional, technological, and global innovation systems, alongside debates on mission- and challenge-oriented policy. Second, evolutionary economic geography, including theoretical approaches to understanding specialization, diversification, relatedness, and complexity, which help explain why regional development pathways are often path-dependent and uneven. Third, transition studies, including perspectives on socio-technical systems and imaginaries, highlighting how institutional and cultural elements stabilize or transform existing systems and how visions of the future influence their directionality. Together, these strands inform an integrative perspective on the spatiality of innovation and socio-technical change. Methodologically, the thesis employs a mixed-methods design. Quantitative analyses use patent data to trace the emergence, diffusion, and geography of innovation activities, complemented by novel datasets and indicators such as machine-learning-based classifications of patent texts, large-scale web-mining of firms and municipalities, and a geolocated corpus of German news articles. Sequence analysis is introduced as a methodological innovation, enabling the study of region-specific temporal trajectories. In addition, qualitative studies provide conceptual and inductive insights into socio-technical imaginaries, legitimacy struggles, and actor constellations. The cumulative work shows that innovation and socio-technical change are spatially uneven, shaped by regional preconditions, multi-scalar linkages, and technology-specific features. It demonstrates the value of combining quantitative and qualitative approaches to capture both systematic evidence and contested, imaginative dimensions. Overall, the thesis contributes to geographically informed understandings of sustainability transitions and to debates on policies fostering inclusive, place-sensitive pathways of change.
Investigating Quasiparticle Interactions in the Far-Infrared
(2026) Anders, Daniel
This dissertation investigates ultrafast charge-carrier dynamics and quasiparticle interactions in semiconductors using terahertz (THz) spectroscopy. The THz spectral range provides direct access to low-energy excitations such as intraexcitonic transitions and free-carrier dynamics, making it a powerful probe of many-body interactions in photoexcited semiconductor systems. Using optical pump–terahertz probe spectroscopy and broadband THz emission measurements, several aspects of carrier dynamics in bulk and low-dimensional semiconductors are explored. First, broadband and gapless THz radiation is generated in bulk germanium via phase-controlled quantum interference currents driven by two-color optical excitation. This approach enables efficient emission across the entire THz spectral range and provides insight into the underlying photocurrent generation mechanisms. The dissertation further investigates the formation dynamics of excitons in (Ga,In)As multi-quantum wells following nonresonant optical excitation. Time-resolved THz spectroscopy reveals that excitons emerge from an initially created electron–hole plasma on two distinct timescales: a fast component of approximately 10 ps and a slower component of about 250 ps. By introducing a differential probing method based on weak and strong THz fields, the longstanding discrepancy in reported exciton formation times is resolved. In addition, the interaction of incoherent excitons with an additional electron–hole plasma is studied using a double optical pump–THz probe scheme. The results show that elastic and inelastic scattering processes are governed primarily by the excess energy of the additional carriers rather than their density. Despite excitation energies exceeding the exciton binding energy, inelastic scattering occurs only when suitable final states are available, consistent with predictions from Fermi’s golden rule. The screening of excitonic states by additional charge carriers is investigated by monitoring the transient shift of the intraexcitonic 1s–2p transition. The measurements provide direct access to the time-dependent exciton binding energy and reveal that the screening strength scales linearly with carrier density while the screening time is determined by the carrier excess energy. Finally, transient excitonic states induced by intense optical fields are demonstrated. Detuned optical excitation produces short-lived excitonic resonances that exist only during the temporal overlap of pump and probe pulses and manifest as blue-shifted THz absorption features. Together, these results provide new insight into ultrafast exciton formation, many-body interactions, and THz generation mechanisms in semiconductor systems, highlighting the capabilities of terahertz spectroscopy as a powerful tool for probing quasiparticle dynamics in condensed matter.
Fighting Poverty with Sheep in Armenia: The Role of Hope
(2026) Weichbrodt, Louisa Joline
Half of the world's population lives in poverty, yet eradicating poverty remains the first Sustainable Development Goal by 2030. Studies evaluating poverty traps and livestock often overlook the role of hope in their analyses, a factor that has recently been recognised as vital in combating poverty. Non-Governmental Organisations implement livestock transfer projects to help families escape poverty and restore hope. To understand the role of hope in these projects, a qualitative approach with interviews was employed, combined with observations of multidimensional poverty indicators to reveal participants' experiences of hope and changes in poverty. The study found that hope is essential for participants' responses to the project and, consequently, supports their exit from poverty. Levels of hope significantly influence perceptions and in turn, actions during participation. Moreover, individual hope was enhanced through livestock transfers, affecting goals, mood, and perception of the future. Subtle changes in multidimensional poverty related to housing and health expenditure planning were also observed. Additionally, development projects can nurture hope by improving mental health, addressing multiple dimensions of poverty, and actively supporting participants' aspirations. Policies can influence both external and internal constraints on poverty and foster hope: firstly, by providing structural grounds for hope; secondly, by informing about available opportunities; and thirdly, by encouraging and supporting aspirations. The government can use policies to promote hopefulness. The fact remains that people living in poverty are not necessarily hopeless. Further research could offer quantitative insights into hope within development contexts. Overall, recognising the role of hope is crucial for designing holistic and effective development projects.
Trafficking and Sorting of Proteins to the Parasitophorous Vacuolar Membrane of Plasmodium falciparum: PfEXP1 as a Model
(2026) Abbasi, Amin
During the asexual blood stage of malaria infection, Plasmodium falciparum develops inside a membrane-bound compartment within the host red blood cell. The membrane surrounding this compartment, the parasitophorous vacuolar membrane (PVM), forms an important interface between parasite and host cell. In addition to exporting soluble effector proteins, the parasite must also direct a specific set of membrane proteins to the PVM. PfEXP1 is a well- established membrane protein of the PVM, but the sequence features that govern its trafficking to this membrane remain unclear. The aim of this thesis was therefore to identify PfEXP1 sequence features that contribute to its targeting to the PVM. To address this question, a panel of plasmid-expressed PfEXP1 variants was generated and analyzed by immunofluorescence microscopy in two parasite developmental stages. In parallel, a biochemical fractionation assay was used to compare whether the different variants behaved mainly as soluble or membrane-associated proteins. Across the construct panel, distal C-terminal truncations generally retained PVM-like localization under the assay conditions used. These variants showed staining patterns consistent with PVM localization and were enriched in the membrane-associated fraction, suggesting that they remained capable of stable membrane association. This indicates that the distal C-terminus is not a dominant determinant of this behavior. In contrast, disruption of the N-terminal region more often resulted in less distinct localization and weaker biochemical evidence for stable membrane association. The transmembrane domain replacement experiments further showed that not all membrane anchors behaved in the same way. Constructs combining the PfEXP1 N-terminal region with a parasite-derived transmembrane segment were more often consistent with PVM-like localization, whereas constructs containing artificial hydrophobic helices did not reproduce clear PVM localization even when flanked by PfEXP1-derived N- and C-terminal regions. These findings argue against a model in which hydrophobicity alone is sufficient for correct targeting. An important limitation of this study was the unexpected predominantly soluble behavior of the exogenous full-length PfEXP1 reference construct, indicating that construct architecture, including tag and linker context, can substantially affect the experimental readout. Taken together, the data support a model in which correct PfEXP1 targeting depends on N-terminal context acting together with an appropriate membrane anchor, whereas the distal C-terminal region appears broadly dispensable in this assay context. More broadly, this work highlights the need for follow-up experiments that directly resolve protein topology, particularly protease- protection assays.
Essays on Monetary Policy, Non-Bank Financial Intermediation and Financial Stability
(2025) Tiza Mimun, Anisa
This dissertation provides an empirical examination of the relationship between monetary policy and non-bank financial intermediaries, commonly referred to as nonbanks.