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Among all attenuation processes, biodegradation plays one of the most important role and is one of the most desirable processes in the environment. To assess biodegradation, a variety of biodegradation test procedures have been developed by several international organizations. OECD guidelines for ready biodegradability testing represent one of the most prominent group of internationally used screening biodegradation tests (series 301A-F). These tests are usually very simple in their designs and allow for the fast and cheap screening of biodegradability. However, because of their stringency, the test conditions are not close to simulating environmental conditions and may lead to unrealistic results. To overcome these limitations, OECD introduced simulation tests which are designed to investigate the behavior of chemicals in specified environmentally relevant compartments. Despite the fact that simulation tests give more insight into the fate of chemicals in the environment, they are not applied frequently as they are often tedious, time consuming and expensive. Consequently, there is a need to provide a new biodegradation testing method that would combine complex testing environment as in simulation tests, easiness in handling and good data repeatability as in screening biodegradation tests. Another challenge is an adaption of the existing biodegradation testing methods to new types of samples, i.e. mixtures of transformation products (TPs). The research on the presence of pharmaceuticals in the environment gained momentum in the 1990s; since then, it has been growing. Their presence in the environment is a wellestablished fact. A wide range of pharmaceuticals is continuously detected in many environmental compartments such as surface waters, soils, sediments, or ground waters. After pharmaceuticals reach the natural aquatic environment they may undergo a number of processes such as: photolysis (under direct sunlight), hydrolysis, oxidation and reduction reactions, sorption, biodegradation (by bacteria of fungi), and bioaccumulation. These processes, may cause their elimination from aquatic environment, if reaction is complete, or creation of new compounds i.e., transformation products (TPs). What is more, processes, like chlorination and advanced oxidation processes (AOPs), such as H2O2/UV, O3/UV, TiO2/UV, Fenton, and photo-Fenton, or UV treatment which might be applied in water or wastewater treatment, may also lead to the TPs introduction into aquatic environment. The research on the TPs brings many new challenges. From one side, there is a constant need for the the development of a sensitive and reliable analytical separation, detection, and structure elucidation methods. Additionally, there is a need for the preparation of appropriate assays for the investigation of properties of new compounds, especially those answering the question if TPs pose a higher risk to the aquatic ecosystems than their parent compounds. Among numerous groups of pharmaceuticals, two are of great importance: antibiotics since they might promote emergence and maintenance of antimicrobial resistance in the aquatic environment; and cytostatic drugs. Cytostatic drugs can exert carcinogenic, mutagenic and/or teratogenic effects in animals and humans. The challenges of biodegradation testing presented in this thesis, encompasses these different areas of interest and was divided into three objectives: 1) Identification of the knowledge gaps and data distribution of the two groups of pharmaceuticals antibiotics and cytostatic drugs (article I); 2) Increasing the knowledge on biodegradation of cytostatic drugs and their TPs (articles II, III, and IV) and 3) Establishment of a biodegradation test with closer to simulation tests conditions, that could be affordable and to support better understanding on processes in water sediment interface construction - screening water-sediment test. Further validation of the test with an insight into sorption and desorption processes (articles V and VI).
Derivatives are contracts between two parties, a buyer and a seller. The contract will be fulfilled in some point in the future at a predetermined price. The value of those contracts is based on an underlying entity which can be a traded asset or even the weather. Derivatives contain chances, but also risks, investor should be aware off. This thesis aims to deeply analyze two derivative products in the German market and one risk for each which influences the prices of those products. The first part of this thesis focuses on warrants and the issuer's credit risk involved. It finds evidence that the issuer's credit risk influences the connection between warrant characteristic and its prices. Over time this connection is unstable partly driven by the issuer's credit risk. The second paper of this thesis shows that issuers seem to use their credit risk systematically to influence warrant prices. Evidence is found that the changes in credit risk are not fully included in the prices directly, but that the adjustment to the new level of credit risk takes several days. In addition, the issuer's adjustment to changes in credit risk are different for credit risk increases than for credit risk decreases. Especially after financial crisis, in more stable times, evidence is found for such adverse pricing pattern. The third part of the thesis focuses on energy derivatives traded at the Europe Energy Exchange and analyses the influence of weather parameters on energy derivatives with different load profiles and time horizons. This part of the thesis finds that especially wind speed and sun hours have a strong influence on energy derivatives. However, not all products are influenced in the same manner. Products with a longer time horizon are influenced less than the product with a short horizon. Moreover, products comprising hours of the day where energy consumption is expected to be higher are influenced stronger than products comprising hours of a day with lower time consumption. The thesis shows that derivatives are not alike and that it is needed for future research to differentiate between products and the risks which are involved. Since even though we classify them all as derivatives the risks influencing the derivative´s prices do vary tremendously.
Research on motivational and cognitive processes in entrepreneurship has commonly relied on a static approach, investigating entrepreneurs' motivation and cognition at only one point in time. However, entrepreneurs' motivation and cognition are dynamic processes that considerably change over time. The goal of this dissertation is thus to adopt a dynamic perspective on motivational and cognitive processes in entrepreneurship. In three different chapters, the work examines dynamic changes in the level and impact of three different processes, i.e., creativity, entrepreneurial passion, and opportunity identification. In Chapter 2, the thesis develops a theoretical model on the alternating role of creativity in the course of the entrepreneurial process. The model emphasizes that the effects of two components underlying creativity, i.e., divergent and convergent thinking, considerably change both in magnitude and in direction throughout the entrepreneurial process. In Chapter 3, the author establishs and empirically tests a theoretical model on entrepreneurial passion. The theoretical analysis and empirical results show that the relationships between feelings of entrepreneurial passion, entrepreneurial self-efficacy, and entrepreneurial success are dynamic and reciprocal rather than static and unidirectional. In Chapter 4, the author develops and tests a theoretical model on the effect of entrepreneurship training on opportunity identification over time. The theoretical and empirical investigation indicates that entrepreneurship training effects systematically decay over time and that action planning and entrepreneurial action sustain the effects in the long term.
Micro- and small enterprises are of great importance for the economic growth in developing countries, as they contribute to employment creation and innovation. In light of their economic relevance, several approaches to support micro- and small enterprises have emerged, including building human capital through business trainings. However, the effects of existing business trainings on entrepreneurial success have so far been limited. One promising alternative training approach that has emerged in the last years is personal initiative training, which teaches self-starting, future-oriented, and persistent entrepreneurial behavior. This dissertation helps to improve the understanding of personal initiative training by shedding light on the mechanisms through which it affects business success, on supporting factors, and on its long-term impacts. Chapter 1 provides an overview on the topic of personal initiative training for entrepreneurs in developing countries. Chapter 2 introduces personal initiative training and other proactive behavior trainings in various contexts of work, including entrepreneurship. The chapter presents action regulation theory and the theory on personal initiative as the theoretical foundation of the training. In addition, the chapter provides insights into training and evaluation methods and makes recommendations for the successful implementation of personal initiative training. Chapter 3 offers a first answer to the question how personal initiative after training can be maintained over time. The chapter introduces training participants' need for cognition as beneficial factor for post-training personal initiative maintenance. Chapter 4 explains how action regulation trainings like personal initiative training contribute to poverty reduction in developing countries by supporting entrepreneurial success. Chapter 5 enlarges upon the topic of personal initiative training for entrepreneurial success in developing countries. The chapter focuses on how personal initiative training supports female entrepreneurs in developing countries by helping them to overcome the uncertainty involved in entrepreneurial actions. Chapter 6 summarizes the overall findings and illustrates the theoretical and practical implications that result from this dissertation. In sum, this dissertation makes a contribution to the better understanding of personal initiative training and its effects on entrepreneurship in developing countries and thereby helps to create effective interventions to combat poverty in developing countries.
In 2013, the European Commission adopted the so called "Entrepreneurship 2020 Action Plan" to ease the creation of new ventures and to support the takeover of existing firms. The goal is to create a supportive environment for entrepreneurs to thrive and grow (European Commission 2013). This shows that the European Union puts its efforts to support small firms as they are seen as means for Europe's sustainable economic growth. However, the successful processes of growth and investment are complex and depend on different determinants. The present thesis focuses on the firm level and analyzes in three independent articles: how small firms invest over time, how new ventures grow and which variables influence growth, how small firms grow after business takeover and which variables influence growth. The framework that connects these articles forms the content-related focus on the early stage of development of small firms and the methodological and analytical approaches that comply with up-to-date and adequate statistical analysis techniques. Supported by an extensive dataset, which is the foundation of all three articles, it is possible to investigate empirically different open research questions using bivariate and multivariate analysis techniques. Thus, this thesis also serves the research needs for more multivariate analyses for small firms, for which so far mainly cross-sectional studies have been conducted.
The dissertation project focuses on empirically investigating consumers' attitudes, motivations and purchasing decisions regarding sustainable products. The focus on this micro perspective, however, does not reflect consumers' roles within the transformation towards sustainable consumption. Therefore, the present framework paper puts the included papers into a greater context and evaluates the findings on a meta-level by applying an enhanced transition management theory. The analysis underlines that consumers' limited personal capabilities are an underlying reason for unsustainable practices. Therefore, the active engagement not only of consumers, but also of companies is required if the transformation is to be successful. If companies actively support consumers in making sustainable choices, consumers can engage in sustainable consumption with only low cognitive efforts. On this basis, genuine sustainable choices are enabled. The dissertation provides practical implications by highlighting potential measures which will help to promote sustainable products from niches to mainstream. In sum, the dissertation project enhances academic understanding of consumers´ sustainable purchasing behavior and reveals the potential of integrating such insights into the management of transformations towards sustainable consumption.
This thesis aims at contributing to the better understanding of the roles of international and domestic institutional and governance patterns for corporate sustainability practices. By combining governance and new institutionalism approaches it bridges the gap between the close look at specific corporate sustainability (CS) policies and the broader view on institutional frameworks. The qualitative comparative approach aims to provide deeper insights on the implementation of different governance schemes by transnational corporations ((TNC). Finally, the conclusions might allow for the development of a) recommendations for the balancing of TNCs' CS management between global and domestic requirements, and b) policy recommendations in the field of CS governance. The overarching research question is as follows: What role do national governance patterns play in comparison to global governance practices in shaping the corporate sustainability (CS) management of transnational corporations (TNCs)? In order to further operationalize this research objective, it is structured into three subquestions: (1) What are relevant institutional factors and global governance patterns for corporate sustainability/ Corporate Social Responsibility (CSR)? (2) What are relevant institutional factors and national governance patterns for corporate sustainability/CSR in Germany, the US, and India? (3) How do these national and global governance patterns influence TNCs' CS management? The first two questions aim at tracing the institutional framework and governance patterns at both national and international levels by identifying norms, stakeholder expectations, prevalent modes of governance and actors involved in governance processes. On this basis, the third question targets TNCs' reaction to internationally varying governance patterns. Here, it is of main interest how relevant governance instruments are perceived by business actors and to which extent their sustainability management at the companies' headquarters and subsidiaries reflect global and national institutional and governance patterns. In order to answer these questions, literature research and a structured qualitative analysis have been conducted. The concepts of CS and CSR build the basis to analyze how TNCs and their subsidiaries manage their social and ecological corporate responsibilities. Against this conceptual background, the research question is approached empirically by the means of an international comparison. Three institutionally highly diverse countries were chosen: Germany, India and the US. India, an emerging market economy, was included to increase the diversity of the sample and to close the research gap indicated above. In order to identify the differences in governance for CS in these three countries, document analyses and 42 guideline-based interviews with experts from governments, NGOs, trade unions and trade associations were carried out. At the same time, global governance instruments for corporate sustainability – which are already relatively well researched - were identified by analyzing the relevant secondary literature. In a second step, in order to explore how TNCs strategically deal with the multitude of different governance approaches at their headquarters and subsidiaries, three case studies of Germany-headquartered transnational corporations in the chemical and engineering industries (Siemens, BASF and Bayer) have been conducted.
Organizational culture is widely acknowledged to be a driver of organizational effectiveness. However, existing empirical research tends to focus on investigating the links between individual, isolated culture dimensions and effectiveness outcomes. This approach is at odds with the theoretical roots of organizational culture and does not do justice to the complex reality that most organizations face. This issue is addressed by this dissertation, which is comprised of four studies. Study 1 investigated the psychometric quality and cultural equivalence of three culture measures in a German context, based on a sample of 172 employees in a bank. The results suggested that the German versions of the Denison Organizational Culture Survey and the Organizational Culture Profile performed satisfactorily, while results regarding the GLOBE survey fell short of expectations. Study 2 reviewed the literature on the link between culture and effectiveness with a focus on studies that treat organizational culture as a holistic phenomenon. The review yielded four kinds of holistic approaches (aggregation-based, agreement-based, moderation- or mediation-based, and configuration-based). Study 3 investigated how a change in organizational culture induced by an M&A project impacts employee commitment. Based on a sample of 180 employees in a German organization, the findings suggest that individuals perceive cultural change differently, that cultural stability is positively related to employee commitment, and that group-level leader-member exchange and individual self-efficacy moderate this relationship. Study 4 introduced a new theoretical perspective (set theory) and a novel methodology (fuzzy set qualitative comparative analysis) to the field of organizational culture. Across two samples (1170 employees in a financial service provider and 998 employees in fashion retailer), results indicated that culture dimensions do not operate in isolation, but jointly work together in achieving different effectiveness outcomes.
Online advertising has become one of the most important dimension of corporate communications. In recent years, a new form of advertising on the Internet has emerged: real-time advertising. Among others, it allows companies to identify potential customers and target them with respect to their interests. In this way, real-time advertising can increase advertising effectiveness and it could, at the same time, improve user experience. With the emerge of this new form of advertising, statistical models have become even more important because they are now being increasingly used to predict online user behavior. The articles included in this dissertation analyze user-level clickstream data generated during multi-channel advertising campaigns (including TV advertising) and during real-time auctions. The goal of the analyses conducted here is to better understand advertising effects and to support decision-making in this context. Most of the analyses are based on Bayesian models. These models allow for a very flexible structure, which enables researchers to model, for instance, heterogeneity across different types of users or non-linear parameters such as users´ reaction times and exponential decay of advertising effects. In addition, these models allow for the inclusion of prior knowledge of parameter distributions, and, therefore, they are well suited for iterative analyses based on clickstream data. Bayesian models can be evaluated in different ways. Instead of only relying on statistical metrics, the articles included in this dissertation aim to estimate the economic value of these models based on their predictive performance. Although this measure can only approximate their true economic value, this approach can be used to compare and evaluate different models and to illustrate the impact of predictive analyses for companies in the context of big data. This dissertation contributes to both information systems research and marketing research and has many managerial implications. First, a process is developed to determine optimal sample sizes representing the best balance between computational costs and predictive accuracy in e-commerce in particular and big data contexts in general. In practice, this process can be used to reduce infrastructure and computational costs. Second, the articles included here describe models that can be used to measure the impact of television ads on users' online shopping behavior. The models can provide insights concerning the effectiveness of individual television ads, the interactions between different advertising channels and the difference in user behavior of TV-induced customers and their non-TV-induced counterparts. Thereby, the models could support decision-making with respect to future advertising campaigns and targeting. Third, the articles describe several possibilities to extend and improve decision support systems currently used in e-commerce and marketing. These improvements enable practitioners to predict users´ interests for arbitrary products and services by using corresponding websites as dependent variables. This approach can be used to improve the effectiveness of real-time advertising campaigns, especially those intended to raise brand awareness among customers.
Members of Western organizations differ in various diversity attributes. In response, research aims to provide evidence-based recommendations on how to effectively manage diversity in teams. Within diversity research, the diversity faultlines approach has been particularly fruitful. It considers the impact of the alignment of multiple diversity attributes in teams. Strong diversity faultlines are associated with the emergence of relatively homogeneous subgroups in teams and have an overall negative impact on team processes and outcomes. This dissertation investigates factors that mitigate the detrimental consequences of strong diversity faultlines in teams, namely pro-diversity beliefs. It extends faultline literature beyond the conventional focus on processes and outcomes related to team members by emphasizing the leaders' perspective. The three empirical papers included in this dissertation systematically examine how strong pro-diversity beliefs can help unleashing the positive effects of team diversity despite strong faultlines. The first paper highlights the role of leaders' pro-diversity beliefs in mitigating the negative impact of diversity faultlines on two team processes: perceived cohesion and social loafing. Moreover, it compares the impact of socio-demographic faultlines (based on gender and age) and experience-based faultlines (based on team tenure and education level). Data was collected in a multisource field sample with 217 team members nested in 44 teams and the corresponding leaders. The second paper takes the impact of members' pro-diversity beliefs into account. It examines whether the impact of sociodemographic faultlines on performance is contingent on leaders' and members' pro-diversity beliefs. Moreover, the research group assumed that aggregate LMX would mediate this relationship. In a multisource data set obtained from 41 teams with 219 members and the corresponding leaders working for the German Ministry of Foreign Affairs, the investigators found partial support for their hypotheses. As expected, the impact of strong socio-demographic faultlines on diplomats' performance was least negative when both leaders and members held strong pro-diversity beliefs. The third paper zooms into processes and outcomes related to team leaders. It investigates how leaders' pro-diversity beliefs and their perceptions of members' prodiversity beliefs in teams with strong socio-demographic faultlines impact leaders´ task role assignment, performance expectation, and motivation. The research group conducted two experimental studies with students, one in Germany (N=55) and one in the US (N=134). Findings showed that strong pro-diversity beliefs held and perceived by leaders made them assign task roles that cross-cut rather than aligned with the subgroup structure created by faultlines. Moreover, leaders' perceptions of members' pro-diversity beliefs, but not their own beliefs, had a positive impact on their motivation, mediated by their performance expectation.