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The existence of the common ash (Fraxinus excelsior L.) is acutely threatened by ash dieback, caused by the fungus Hymenoscyphus fraxineus. The disease may lead to reduced pollen flow due to crown damage and tree mortality, which affects the reproductive ecology of Fraxinus excelsior L. However, sexual reproduction in forest trees plays an essential role not only in species conservation and adaptive potential, but also in natural selection and the promotion of genetic diversity. The impending risk of reduced gene flow is therefore of serious concern and threatens the conservation of this valuable tree species. Therefore, it is critical to advance research on the effects of ash dieback on (effective) pollen transport and reproductive ecology of Fraxinus excelsior L. These results can be used to support forest management, such as maintaining ash genetic diversity and promoting the development of natural resistance. Therefore, this study will conduct extensive research in two seed orchards and one floodplain forest in Southern Germany from 2018 to 2021. The main objective of this dissertation was to improve our understanding of gene flow patterns by investigating (effective) pollen dispersal, pollen production and pollen and seed quality of ash trees in relation to their health status.
The main research questions were:
(1) How does ash (effective) pollen transport vary with stand density, ash abundance and meteorology?
(2) Is there a link between mating success and damage to the paternal tree?
(3) Does the health of the ash trees affect pollen and seed quality, as well as pollen quantity?
To answer these questions, different methods were used in the study areas, which differed in topography and degree of stocking. Therefore, not all parameters were examined at every site and in every year, depending on the issue concerned. The health status of the ash trees was assessed every year in July using a six-level vitality score. In addition, phenological observations were made annually in spring according to the BBCH code to determine different phenological stages such as beginning of flowering, full flowering, flower wilting and end of flowering.
Aerobiological pollen measurements were carried out in the two orchards in 2019 and 2020 using self-constructed gravimetric pollen traps of the Durham type. One of the traps was placed in the center of each orchard and up to five additional traps were placed at a maximum distance of 500 m from the orchard. Five vaseline-coated slides were attached to each trap (one in each cardinal di-rection and one horizontally) to measure pollen transport (N=4) and weekly cumulative pollen position (N=1). To study the influence of meteorological parameters, a climate station was placed in each orchard. In addition, other anemometers or data loggers for air temperature and relative humidity were installed.
For paternity analyses, cambium samples were collected for genotyping from branches and stumps of 251 ash trees in a seed orchard and floodplain forest. In addition, seeds were collected from 12 parent trees per site with different health status. Genetic analyses were performed to determine paternal trees using nuclear microsatellites. Paternities were assigned using the likelihood model implemented in Cervus 3.0.7 software.
Pollen viability of ash trees with different health status were studied at all three sites. Pollen production in the two seed orchards and seed quality in one orchard and the floodplain forest. For this purpose, inflorescences of 105 ash trees (pollen production), pollen of 125 ash trees (pollen viability) and seeds of 53 ash trees (seed quality) were collected. Pollen production was estimated from flower to tree level and pollen viability was determined using the TTC (2,3,5-triphenyltetrazolium chloride) test. In addition, pollen storage experiments were carried out to investigate the influence of meteorological factors on pollen viability. Pollen were stored for various periods at different temperatures and humidity conditions and their viability was determined. Seeds were analyzed for quantity and quality (solid, hollow grains, insect damage and germination) and seed quality was determined by both stratification and the TTC test.
The results on aerobiological pollen transport showed that pollen transport is related to meteorology, phenological development and the topography of the study site. The Schorndorf orchard, located on a slope, showed higher pollen levels at the downslope traps, likely due to the transport of pollen by cold air flow. The prevailing wind direction often corresponded with the compass direction in which the highest pollen deposition was measured. When analyzing the pollen data for individual traps, the highest pollen levels were measured outside the orchards in 2019, a year with low flower development. In contrast, most pollen were collected inside the orchard in the pollen-rich year 2020. This suggests that trees outside the orchard can potentially contribute more to pollination in a poor pollen year. In Emmendingen, minor difference in pollen quantity was found between traps at 1.5 m and 5 m height, but there were temporal differences indicating vertical variation in pollen availability. Ash pollen were found to be transported over a distance of more than 400 m, with the amount of pollen decreasing with increasing distance. About 50 % less pollen were measured at a distance of 200 m, but even at a distance of 500 m more than 10 % pollen were still detected.
The studies on effective pollen transport showed similar results: the average distance between father and mother tree was 76 m in the orchard and 166 m in the floodplain forest, with pollination success decreasing considerably with increasing distance. Despite the dense tree cover, the longest distances (> 550 m) were recorded in the floodplain forest. Based on this and the fact that 66.5 % cross-pollen input was recorded in the seed orchard, it can be assumed that pollination does not only involve local sources. However, self-pollination generally did not have a substantial effect on ash reproduction. In terms of health status, both healthy and slightly damaged parent trees showed similar mating success. However, in severely damaged trees almost no flowering could be documented. In general, it was demonstrated that both healthy and slightly diseased fathers sired more offspring than severely diseased ash trees.
The effect of ash dieback on pollen production showed no significant difference between healthy and diseased ash trees, although 53 % of severely diseased male ash trees did not produce flowers. In terms of pollen viability, there was a tendency for diseased ash trees to have less viable pollen than healthy ash trees. In addition, the viability experiments revealed a strong influence of prevailing temperatures on pollen viability, which decreased more rapidly under warmer conditions. There was also no statistical difference in seed quality between ash trees of different health status. However, non-viable seeds were often heavily infested with insects.
In summary, the studies show that a variety of factors influence the reproductive ecology and (effective) pollen transport of ash trees. However, the fact that severely affected ash trees are linked to a reduced flower production and lower pollen quality suggests that as health deteriorates, reproductive capacity also declines. It is therefore likely that severely diseased ash trees have a limited ability to pass on their genes to the next generation. Paternity analyses also suggest that high vigor has a positive effect on reproductive success and that pollen transport can occur over long distances. As susceptibility to ash dieback can be passed on from parents to offspring, these reactions to ash dieback may make ash populations less susceptible in the future.
Finance without foundations
(2022)
This thesis examines the role of financial inclusion by way of access to formal financial services such as savings, credit, transfers and payments, in supporting the lives of refugees in protracted displacement in Jordan. It asks if such access enables smoother financial and livelihood transitions as refugees arrive and integrate into their new environments in host countries. It critically evaluates the narrative presented by humanitarian actors supporting financial inclusion as a marketled intervention to support refugee self-reliance. It argues that the limited provision of financial services through mobile wallets and micro-credit is not sufficient to financially integrate refugees. Above all, it demonstrates through the in-depth qualitative research in Jordan that in a context where refugees’ livelihoods are constrained due to a lack of foundational economic rights, financial services can only marginally improve their lives by making it more convenient to receive remittances and humanitarian transfers.
The research is embedded in a larger project called “Finance in Displacement: Exploring and strengthening financial lives of forcibly displaced persons” (FIND), which was initiated in 2019 as a collaboration between the Katholische Universität Eichstätt-Ingolstadt, the Tufts University, and the International Rescue Committee. The project was supported by the German Federal Ministry for Economic Cooperation and Development (BMZ).
In children exposed to any traumatic experience, a conditional prevalence rate of 15.9% was estimated for posttraumatic stress disorder (PTSD; Alisic et al., 2014). In order to achieve best treatment outcomes, selecting evidence-based treatments is necessary (Durlak & DuPre, 2008). For pediatric PTSD, international guidelines recommend the use of manualized trauma-focused cognitive behavioral therapy (TF-CBT; Forbes, Bisson, Monson, & Berliner, 2020; National Institute for Health and Care Excellence, 2018; Phoenix Australia Centre for Posttraumatic Mental Health, 2013) and many effectiveness studies and initiatives (e.g. Goldbeck, Muche, Sachser, Tutus, & Rosner, 2016; Jensen et al., 2014; National Child Traumatic Stress Network, 2012) disseminated the TF-CBT manual of Cohen, Mannarino and Deblinger (2006, 2017; specific TF-CBT). However, the uptake of evidence-based treatments such as specific TF-CBT into practice is strongly affected by service providers’ attitudes toward evidence-based practice (EBP; Aarons, 2004; Aarons, Cafri, Lugo, & Sawitzky, 2012; Aarons, Sommerfeld, & Walrath-Greene, 2009; Moullin, Dickson, Stadnick, Rabin, & Aarons, 2019). These attitudes can be measured with the Evidence-Based Practice Attitudes Scale-36 (EBPAS-36; Rye, Torres, Friborg, Skre, & Aarons, 2017). In Germany, several effectiveness trials are underway further disseminating specific TF-CBT (Rosner, Barke, et al., 2020; Rosner, Sachser, et al., 2020) but a reliable and validated German version of the EBPAS-36 is missing. In addition, in terms of pooled effect sizes (ES), only one review evaluated specific TF-CBT 10 years ago (Cary & McMillen, 2012). Furthermore, little is known about the stability of its treatment effects, the concordance between children and adolescents’ and their caregivers’ ratings regarding the youths’ symptoms in this context as well as the influence of the heterogeneity of instruments used by individual studies.
Therefore, the aims of this dissertation were fourfold: Publication 1 pooled ES for specific TF-CBT regarding posttraumatic stress symptoms (PTSS) and secondary outcomes to provide an update of the literature. Large improvements were found across all outcomes and results were favorable for specific TF-CBT compared to all control conditions at post-treatment. Publication 2 pooled ES for specific TF-CBT at 12-month follow-up for the same outcomes to evaluate the stability of treatment effects and investigated concordance between participants and caregiver ratings. Again, large improvements were evident across all outcomes and TF-CBT was superior to active treatments and treatment as usual at 12-month follow-up. No significant differences were detected between participant and caregiver ratings with high reliability across almost all outcomes and assessment points. Publication 3 produced a validated German translation of the EBPAS-36 (EBPAS-36D) to facilitate EBP implementation research in Germany. Good psychometric properties and validity of the EBPAS-36D were confirmed. As additional content, this dissertation provides an unpublished report on the pooled ES of publication 1 differentiated by instruments used to assess the outcomes. ES did not differ by the instrument used to assess the respective outcome.
The conclusions that can be drawn from the studies as well as their limitations are discussed in the final section. While the EBPAS-36D was successfully validated and specific TF-CBT was strongly supported, several issues were identified that need further research attention.
Background:
Pollen allergies are widespread around the world, making the study of pollen levels in and around cities a task of high importance. This is also related to the fact that an increasing number of people is living in cities and urban areas are expanding. In addition, environmental changes in the context of climate change are expected to alter plant characteristics that affect the amount of pollen in the air. In order to assess the allergy risk, information on pollen that people are exposed to is needed. Monitoring of aeroallergens in cities is often conducted using a single trap. This trap can provide information on background pollen concentration, however, it does not reflect temporal and spatial variations of pollen at street level of the heterogeneous urban environment. The amount of pollen in the air is the result of a number of processes, one of which is pollen production. Pollen production is expected to be altered by climate change and is influenced by environmental factors such as temperature or air pollutants. To further investigate variations of allergenic pollen in cities, this thesis focuses on these central research questions:
- Are there differences in the amount of airborne pollen between urban and rural locations and do pollen loads vary at different spatial and temporal scales?
- What is the influence of land use and management on pollen loads?
- Is there a difference in pollen production of allergenic species between urban and rural locations and can the influence of environmental factors be detected?
Data and Methods:
Data on airborne pollen were gathered in two study areas with various pollen traps. In Ingolstadt, Germany, background pollen concentrations of Poaceae were measured in 2019 and 2020. Additionally, a network consisting of twelve gravimetric pollen traps was set up during the grass pollen seasons of those years. For an additional sampling campaign, portable volumetric traps were used to measure pollen concentration at street level. Investigations were also conducted in Sydney, Australia, where concentrations of Poaceae, Myrtaceae and Cupressaceae pollen and Alternaria spores were measured during three pollen seasons from 2017 to 2020. In the summer of 2019/2020, additional ten gravimetric traps were set up. For both study areas, pollen season characteristics and temporal and spatial variations of pollen concentrations and pollen deposition were analysed in context with land use, land management and meteorological parameters.
Furthermore, pollen production of the allergenic species Betula pendula, Plantago lanceolata and Dactylis glomerata was investigated in the Ingolstadt study area along an urbanisation gradient, which covered different types of land use. In total, 24 individuals of B. pendula, 82 individuals of P. lanceolata and 54 individuals of D. glomerata were analysed. Pollen production was compared between urban and rural locations and the influence of air temperature and the air pollutants nitrogen dioxide (NO2) and ozone (O3) was assessed. Air temperature was measured in the field and pollutant concentrations were computed using a land use regression model.
Results and Discussion:
In Ingolstadt, grass pollen concentrations and deposition were generally higher at rural than at urban locations as documented in peak values and seasonal totals. Diurnal variations however, did not vary between urban and rural locations. Grass pollen levels were linked to local vegetation and land use but also land management, as grass cutting was reducing pollen levels in the surroundings.
In Sydney, pollen season characteristics varied between the seasons and we found significant correlations between daily pollen and spore concentrations and meteorological parameters. There were significant positive correlations with air temperature for all analysed pollen and spore types. Correlations with humidity (Myrtaceae, Cupressaceae, Alternaria) and precipitation (Myrtaceae, Cupressaceae) were negative. Spatial variations of pollen deposition were observed, but there were no correlations with land use. This could be attributable to the drought before and during this sampling campaign as well as the temporal setting of the sampling campaign.
The results from both study areas suggest that local vegetation is the main influence on the pollen amount at street level. However, when the season’s intensity decreased, other influences such as resuspension or pollen transport become more important. Analyses of pollen production revealed statistically significant differences between urban and rural locations for B. pendula and P. lanceolata. Pollen production decreased with temperature and urbanisation for all species, however, pollen production varied at small spatial distances within species. For increasing air pollutant levels, decreases were observed for B. pendula and P. lanceolata, but increases for D. glomerata. These results suggest that environmental influences seem to be species-specific.
The results from the studies contribute to the knowledge on temporal and spatial variations of airborne pollen in cities, as well as on pollen production of allergenic species. They highlight the importance of pollen monitoring at street level and at different locations in cities to assess the amount of pollen that people are exposed to. Further research in this area should investigate the influence of land management, which was identified to influence the amount of pollen in the air, and which could be a mitigation strategy for allergy-affected people. In addition, pollen production should be further examined with different kinds of experiments, as it is the major influence of ambient pollen concentration in the air.
This cumulative dissertation investigates the newly emerged phenomenon of customer success management (CSM). CSM has received a significant amount of attention from academics and practitioners alike. However, the body of academic literature is still in its infancy, especially when comparing CSM’s relevance to the field of relationship marketing.
Manuscript 1: Zakrzewski, K., Krause, V., Pfaff, C. & Seidenstricker, S. (2023). Is customer success management a new relationship marketing practice? A review, definition, and future research agenda based on practice theory.
Manuscript 2: Zakrzewski, K., Krause, V., Eberl, D. & Rangarajan, D. (2023). Dynamic & proactive segmentation of post-sale customer relationships in B2B subscription settings: The customer health score.
Manuscript 3: Zakrzewski, K. (2023). Customer success management - closing a capability gap in the customer-focused structure toward customer centricity in B2B service contexts.
The first manuscript adopts a new approach to the investigation of CSM, providing a practice-based definition that distinguishes CSM from other relationship marketing constructs. By utilizing the 3 Ps framework of practice theory (praxis, practices, and practitioners), the definition of CSM as a strategic function was refined. In addition, the second manuscript utilized praxis to develop the customer health score, which can be used as an indicator for the dynamic and proactive segmentation of customers. The third manuscript builds on this functional definition to show how CSM’s organizational embeddedness can help overcome barriers to customer centricity by enabling adaptive organizational capability.
In forecast combination, multiple predictions are linearly combined through the assignment of weights to individual forecast models or forecasters. Various approaches exist for defining the weights, which typically involve determining the number of models to be used for combination (selection), choosing an appropriate weighting function for the forecast scenario (weighting), and using regularization techniques to adjust the calculated weights (shrinkage). The papers listed address the integration of the three approaches into holistic data analytical models.
The first paper develops a two-stage model in which weights are first calculated based on the in-sample error covariances to minimize the error on the available data by combining the individual models. Based on the selection status of a model, the weight of an individual model is then linearly shrunk either toward the mean or toward zero. The selection status is thereby derived apriori from information criteria, where Contribution 1 introduces the selection based on the model’s in-sample accuracy and performance robustness under uncertainty.
Contribution 2 modifies the two-stage model to shrink the forecasters’ weights non-proportionally to the mean or zero. Further, a new information criterion based on forward feature selection is proposed that iteratively selects the forecaster that is expected to achieve the largest increase in accuracy when combined.
Contribution 3 extends the iteration-based information criterion presented in the second contribution to consider diversity gains in addition to accuracy gains when selecting and combining forecasters.
A one-stage model for simultaneous weighting, shrinking, and selection is finally built and evaluated on simulated data in Contribution 4. Instead of requiring a prior selection criterion, the model itself learns which forecasters to shrink to the mean or to zero, while relying on a new sampling procedure to tune the model.
"Present Bias in Choices over Food and Money: Evidence from a Framed Field Experiment" - this paper presents results from a field experiment investigating dynamically inconsistent time preferences over real food choices and commitment take-up in a natural environment. We implement a longitudinal consumption experiment with a continuous convex budget: College students repeatedly choose and consume lunch menus at their college canteen. We not only allow for a full continuum of healthy or unhealthy foods; we also explicitly design the consumption stage to comply with the consume-on-receipt assumption: utility is created right after handing out the food. The paper also focuses on the implications for effective policy design: It sheds light on consumers' tendency to utilize different types of self-control devices to commit to personal consumption plans. We further compare inconsistent behavior between convex food and money choices to investigate the applicability of monetary reward studies to natural behavior. We find no correlation between time parameters in food vs. money tasks. Utility estimates from food choices suggest that dynamically consistent individuals substitute internal self-control with commitment take-up. Non-committing individuals tend to be present-biased and naive about their inconsistency.
"Dynamic Inconsistencies and Food Waste: Assessing Food Waste from a Behavioral Economics Perspective" - this paper investigates the link between dynamically inconsistent time preferences and individual food consumption and waste behavior. Food waste is conceptualized as unintended consequence of consumption choices along the food consumption chain: Because inconsistent individuals postpone the consumption of healthier food at home, storage time is prolonged and food more likely to be wasted. Capitalizing on a rich data set from a nationally representative survey, the paper constructs targeted measures of time-related food consumption and waste behaviors. In line with the theory, the paper finds that more present-biased individuals waste more food. The mechanism can be empirically supported: Although dynamically inconsistent individuals plan their food consumption, they deviate from their consumption plans more compared to consistent individuals. Deviation behavior is significantly associated with food waste. The paper points to the importance of considering dynamic inconsistencies at different stages of the food consumption process to foster the intended effects of food policies (increase in healthy nutrition) and diminish unintended consequences (increase in food waste).
"Economic Behavior under Containment: How do People Respond to Covid-19 Restrictions?" - this paper investigates the effects of policy interventions on individual decision-making and preferences by looking at a period of unprecedentedly strict regulation: the Covid-19 pandemic. Focusing on Germany, we measure regulatory strictness by calculating a policy stringency index at the federal state level. Capitalizing on exogenous variation in predetermined election cycles across states, we instrument policy stringency with the distance to the next election. Results support a positive relation between weeks to next election and state policy stringency. Leveraging a nationally representative short panel, the paper exploits this exogenous variation in policy stringency across states and over time to assess behavioral changes in different economic domains. The paper finds that government restrictions increase working from home and the provision of childcare at home, while it reduces the number of grocery shopping trips. Containment policies also affect risk preferences and fear of Covid-19: individuals become more risk-averse and afraid of Covid-19 as a consequence of stricter policies. The results are robust against various different model specifications.
Exposure to more than one language influences children's language development (Kehoe & Kannathasan, 2021). It has been shown that particularly the relative amount of language input bilingual children receive influences their language development. Bilingual children can never dedicate the same amount of time to either one of their languages as their monolingual peers because their everyday linguistic environment is divided between two languages. This may ultimately lead to typically developing bilingual children with linguistic profiles similar to monolingual children with a language developmental disorder (DLD) if they have reduced contact to one of their languages (Paradis, 2010). For this reason, it is particularly difficult for clinicians (i.e., Speech-Language Pathologists, SLPs) to distinguish between actual language impairment and typical deviations from the (monolingual) norm due to limited language exposure. In Germany, almost half of all children in speech therapy have a bilingual or multilingual language background (Lüke & Ritterfeld, 2011). Despite the high proportion of bilingual children in speech therapy, the assessment and treatment of DLD in this population is still predominantly monoculturally and monolingually oriented (Scharff Rethfeldt, 2016). Previous studies have identified nonword repetition tasks (NWRTs) as promising tools for the clinical differentiation between bilingual typically developing children and children with DLD because they are arguably relatively free from the influence of children's prior language experience (Schwob et al., 2021). However, some researchers have raised the question of whether bilingual children might still be disadvantaged by language-specific characteristics of nonwords (e.g., Chiat, 2015).
In three separate studies, this dissertation will (1) demonstrate the influence of bilingual language exposure on speech sound processing, an essential building block of language development, (2) evaluate how DLD is diagnosed in bilingual children in Germany and which factors contribute to positive attitudes towards bilingualism in SLPs, and (3) investigate whether bilingual children's nonword repetition performance of language-specific versus unspecific (i.e., more language-neutral) nonwords is subject to the influence of their individual language exposure.
In the first study (see chapter 2), the perception and production of Voice Onset Time (VOT) in bilingual Italian-German, monolingual German, and monolingual Italian children was investigated using a combination of neurophysiological and behavioral methods. Forty five-year-old children (16 monolingual German, 24 bilingual Italian-German) participated in the electroencephalographic (EEG) study, in which automatic speech sound processing of Italian- and German-specific VOT contrasts was investigated. To compare the participants language-specific VOT production, in addition to the 16 monolingual German and 24 bilingual Italian-German children, a control group of five monolingual Italian-speaking children were tested with a picture naming task in which the production of language-specific word-initial VOT was recorded based on ten words per target sound. Acoustic measurements were taken in Praat (Boersma & Weenink, 2013). Children's language background was assessed using a parental language background questionnaire. In the second study (see Chapter 3), 66 SLPs from Germany participated in an online survey investigating their attitudes towards bilingualism and their approaches in their daily clinical practice. Finally, in the third study (see Chapter 4), a new NWRT was developed that included Italian- and German-specific as well as language-unspecific nonwords. The NWRT was implemented in an online platform and administered to a group of 26 bilingual Italian-German TD children. Children's repetition performance in the different nonword subcategories was analyzed in the context of their linguistic background (recorded using the same questionnaire as in Study 1).
Study 1 showed that Italian-German bilingual five-year-old children and the monolingual German control group behaved similarly in processing language-specific VOT stimuli. However, differences between the two groups likely related to language exposure were evident in the processing of a German "long lag" stimulus. Surprisingly, the bilingual group had no advantage in processing the Italian "voicing lead" stimuli. This suggests that the bilingual five-year-olds do not (yet) process the Italian contrasts automatically (Yu et al. 2019). Acoustic measures of productive VOT for Italian and German words were consistent with this interpretation. Specifically, bilingual children showed mastery of the German but variability with respect to the Italian VOT contrast. Evidence for crosslinguistic influence (cf. Paradis & Genesee, 1996) was observed. Study 2 showed that there seems to be an imbalance between SLPs' knowledge of the specific requirements for providing their services to bilingual children and their actual application in clinical practice, indicating sufficient awareness but still a relatively high presence of monolingual approaches in the context of speech therapy. Presumably, this is due to a lack of available materials and/or resources. Finally, Study 3 showed that Italian-German bilingual children performed equally well on Italian-specific, German-specific, and language-unspecific nonwords, regardless of their individual language exposure and language dominance patterns, supporting the view that even language-specific NWRTs can be used to clinically assess the language performance of bilingual children with relatively little exposure to either of their languages. However, this result has yet to be replicated and thus confirmed with a group of children with DLD.
In summary, these three studies highlight the gap between scientific research and clinical practice and demonstrate the relevance of clinicians' participation in research projects to (1) improve knowledge transfer between the two fields and (2) promote evidence-based practices in the context of Speech-Language Pathology.
In this thesis, I evaluate different tax policy reforms or tax policies in general with respect to the three pillars of sustainability: the environmental, the economic, and the social pillar. The cumulative dissertation consists of the following four chapters:
Chapter 1: Towards Green Driving - Income Tax Incentives for Plug-in Hybrids (based on joint work with Henning Giese)
Chapter 2: Corporate Taxation and Firm Performance (based on joint work with Dominika Langenmayr, Valeria Merlo, and Georg Wamser)
Chapter 3: Tax Avoidance Using Hybrid Financial Instruments Among European Countries
Chapter 4: Avoiding Taxes: Banks’ Use of Internal Debt (based on joint work with Franz Reiter and Dominika Langenmayr)
The first chapter relates to the environmental dimension of sustainability. More specifically, I evaluate a specific German tax reform that aimed at reducing greenhouse gas emissions in the transportation sector – a key driver of emissions – by fostering green driving. This essay empirically investigates whether a preferential tax treatment for hybrid plug-in company cars was effective in fostering green driving and whether it was cost-efficient.
The second chapter relates to the economic dimension of sustainability. A subgoal towards more sustainability in this dimension is decent economic growth. Chapter 2 of this thesis contributes to the question of how tax policy can foster firm performance which is an important driver for economic growth. This essay empirically investigates the relationship between corporate taxation and firm performance taking into account firm heterogeneity. As tax policy is an essential instrument for reaching political goals like boosting the economy in crises, this essay may provide valuable insights for policymakers.
The third and fourth chapters relate to the social dimension of sustainability. A subgoal towards more sustainability in this dimension is increased international cooperation. With respect to taxation, the global challenge of multinational firms engaging in tax avoidance made international cooperation in tax policy essential in the last decade. Chapter 3 investigates a specific channel of tax avoidance, i.e., tax avoidance with hybrid financial instruments. This legal analysis reveals tax avoidance opportunities among selected European countries and evaluates countermeasures.
Chapter 4 investigates a different channel of tax avoidance, i.e., intragroup debt finance, specifically for the banking sector. I use administrative data to empirically analyse whether and to what extent multinational banks engage in tax avoidance.
Employing a two-pronged approach to analyzing language, this study uses evidence obtained from a large-scale corpus study and psycholinguistic experiments to investigate the Comparative Correlative (CC) construction (e.g. The more we get together, the happier we’ll be) across twenty varieties of English. More than 10,000 tokens from three of the largest corpora of English (COCA, BNC, GloWbE) and experimental data from almost 600 participants from four locations (Texas, South Africa, Singapore, and Kenya) are analyzed using advanced statistical methods, providing striking evidence for a high degree of parataxis between the subclauses of the construction and massive redundancy regarding cross-clausal associations which, it is argued, are best explained with a Usage-based Construction Grammar (CxG) approach that posits the existence of an elaborate network of interconnected mesoconstructions.
Addressing more general questions about the nature of human language, it is argued that this ‘bottom-up’ approach to language can account for one of the most fundamental riddles that the discipline of linguistics is striving to solve: Accounting for the potential of infinite creativity of language based on a finite set of rules. Furthermore, it is claimed that as an inclusive approach to language, CxG is better at accounting for construction-specific features that Mainstream Generative Grammar (MGG)-based approaches have struggled with. As it turns out, the evidence suggests that the English CC construction is anything but ‘peripheral’.
Additionally, this study examines the CC construction from a World Englishes perspective, addressing a significant gap in research: Schneider, for example, has noted that “[o]nly rarely have New Englishes been employed as test cases for general questions of language theory” (2003: 237), and Hundt writes of the challenge of “bring[ing] intricate, quantitative modelling of usage data to bear on theoretical modelling” (2021: 298). Accordingly, this study provides evidence for the predictive power of Schneider’s Dynamic Model (DM) (2003, 2007), which posits that there is a correlation between evolutionary stages of World Englishes and linguistic features. In this context, it is also shown how principles of cognitive approaches to language can explain both generalizations across varieties as well as variety- and DM stage-specific effects. Furthermore, this study provides strong evidence to support Kortmann’s claim of a continuum ranging from Pidgins and Creoles as “deleters” to L1 varieties as “preservers” (2014: 9) of grammatical formatives, contra Mesthrie and Bhatt’s claim of a geographical dichotomy between African and Asian varieties.