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This doctoral thesis examines how European merger control law is applied to the energy sector and to which extent its application may facilitate the liberalisation of the electricity, natural gas and petroleum industries so that only those concentrations will be cleared that honour the principles of the liberalisation directives (IEMD and IGMD ). In its communication on an energy policy for Europe, adopted on 10/01/2007, the Commission emphasized that a real internal European energy market is essential to meet Europe’s three energy objectives, i.e. competitiveness to cut costs for citizens and undertakings to foster energy efficiency and investment, sustainability including emissions trading, and security of supply with high standards of public service obligations (Art. 106 TFEU). The EU issued three pre-liberalisation directives since the 1990s. Dissatisfied with the existing monopolistic structures, i.e. in Germany through demarcation and exclusive concession agreements for the supply of electricity and natural gas, which were until 1998 exempted from the cartel prohibition provision (§ 1 GWB), and the prevalence of exclusive rights on the energy markets, the Commission triggered infringement proceedings against four member states under Art. 258 TFEU. The CJEU confirmed that the Commission has the power to abolish monopoly rights under certain circumstances and the rulings had the effect of convincing the member states to enter into negotiations for an opening up of energy markets owing to the internal market energy liberalization directives of 1996 / 1998 / 2003 / 2009 / 2019 (IEMD and IGMD) . The core element of the IEMD and IGMD is to abolish exclusive rights and offer primarily at least large industrial electricity and gas consumers to choose their supplier (market opening for eligible consumers) and to grant negotiated or regulated third party access to transmission and distribution grids so to address natural monopolies. The second liberalization package of 2003 brought a widening of market opening and acceleration of pace of market opening to a greater number of eligible customers (all non-household consumers since July 2004 and all consumers since July 2007) and an increase in the provisions on management and legal unbundling. In parallel, two regulations regulate the access to cross-border electricity infrastructure (interconnectors) and the third party access to gas transmission networks. Two further Directives addressed the security of natural gas and power supply and a third deals with energy end use efficiency and services , a fourth dealt with the promotion of co-generation and a fifths covers marine environmental policy (Marine Strategy Framework Directive in combination with the Hydrocarbons-Licensing Directive ) backed by the public procurement directive in the energy sector. A regulation covers energy statistics. The implementation of the second energy package was slow and the Commission launched infringement proceedings against 5 member states in front of the CJEU (Art. 258, 256 TFEU). The 3rd energy package of 2009 addressed ownership unbundling of key-infrastructure ownership and energy wholesale and retail supply consisting of three regulations and two directives, deals with independent regulators, an agency for the cooperation of energy regulators (ACER) and cross-border cooperation (the European Network for transmission system operators for electricity and gas [ENTSO-E/G] and a regulation on cross-border grid access for electricity and natural gas. Another new regulation deals with market integrity and transparency . Hence, new regulations regulate guidelines on electricity balancing, congestion management, long-term capacity allocation, the code for grid access and transmission system operation . Other regulations address the guidelines for a European cross-border energy infrastructure, which has to be interpreted in the context of European environmental impact assessment law, the submission of data in electricity markets, establish a network code on demand connection , rule on a network code for grid access for direct current transmission systems, define guidelines on electricity transmission system operation, regulate a network code on electricity emergency , deal with security of natural gas supply and establish a programme to aid economic recovery by granting financial assistance. Finally, Directives promote the usage of renewable energies, regulate common oil stocks, the safety of offshore oil and gas production and the quality of petrol and diesel fuels. The 4th liberalization package consists of a new IEMD2019 and IGMD2019, of a new regulation on European cross-border electricity trade, of a regulation on risk preparedness in the electricity sector, of a new agency for the cooperation of European energy regulators, addresses energy efficiency and rules on good governance in the energy union. Since 2008, the Art. 194 I-II TFEU governs the ordinary legislation procedure in the energy sector (internal market in energy, security of energy supply, energy efficiency, energy saving, renewable energies, interconnection of energy grids) notwithstanding of unanimous decision making in case of energy taxation matters (Art. 194 III TFEU). A brief analysis of the economic implications of concentrations is followed by an assessment of the evolution of European merger control law under Art. 66 ECSCT, Art. 101 and 102 TFEU, the merger control regulation of 1989 and its significant amendments of 1997 and 2004. Then, the theoretical findings are contrasted to the results of recent merger proceedings in the energy sector with a focus on the VEBA/VIAG decision. Several deficiencies are established which limit the efficacy of merger control as a tool of offsetting shortcomings in the secondary EC law with regard to the liberalisation of the electricity and gas supply industry (IEMD and IGMD). Commitments proposed by the parties of a given concentration and accepted by the Commission as being sufficient to remedy a serious potential of dominance may only be of subsidiary relevance to the liberalisation of sectors owing to a number of analytical and practical drawbacks. One dominant drawback relates to the fact that the commitments depend always on parties' proposals and can never be imposed ex officio. Others relate to the blunt authorisations provided by the wording of Art. 6 and 8 MR1997 and MR2004 as to the implementation of undertakings. With regard to acquisitions of U.K. regional electricity companies by EdF, it is elaborated that the current merger control law leaves no scope for reciprocity considerations regarding acquisitions by incumbent companies in liberalised markets even though the acquirer is a protected public undertaking. Moreover, it is established that different decisions apply inconsistent market definitions. By means of the VEBA/VIAG and RWE/VEW cases, the question is addressed which causes are responsible for the established analytical and practical deficiencies of merger control in the energy sector. It is stated that the weaknesses of the IEMD 2009/72/EC and IGMD 2009/73/EC are partly responsible for weak undertakings which do not sufficiently remove the scope for dominance on the affected markets and which do not rule out any possibility of impediments of effective negotiated or regulated TPA and do not remove any commercial incentive of the grid subsidiaries of the vertically integrated companies as to access which discriminates between intra and extra group applicants. It is reported that another argument relates to the limited scope that the Commission has if it wants to remedy deficiencies of written primary law owing to the extraordinary nature of the implied powers doctrine based on the principle of constitutional state. Adverse political influence against competition authorities is also judged. Further, it is analysed that accidental regulation based on incidental provisions imposed on undertakings which may or not implement a concentration is by no means a consistent and non-discriminatory and predictable tool to overcome drawbacks of primary or secondary European law in a given sector owing to the democratic principle and the constitutional state doctrine. It is discussed that secondary legislation with regard to energy networks is inter alia restricted by Art. 345 TFEU and provisions of national constitutions which protect property rights against dis-proportionate expropriations or re-definitions of property. Further, legal authorisations of said calibre will have to be connected to a system of state liability law. Adverse political pressures are considered. The same is true for egoistic national policies which abstain from transnational task forces in order to settle difficulties and disputes. Furthermore, the adverse effect of different stages of the maturity of domestic markets, different consumer patterns and a potential isolation of the system is not neglected, because these conditions make it more difficult to apply consistent standards as to the appropriate market definition in order to facilitate harmonisation. The implementation of the VEBA/VIAG merger is discussed, as the former was further complicated owing to specifically evaluated circumstances which were difficult to predict. Nevertheless, the Commission is not exempted from the duty to take due care concerning potential impediments as to the realisation of parties' commitments. In contrast to the negative aspects, it can be highlighted that the Commission quickly realised flaws of the energy liberalisation project as expressed by the present form of the IEMD and IGMD. Consequently, the co-ordinative and innovative mechanisms of Florence and Madrid were created in order to boost the development of effective cross border trade - i.e. tariff systems and interconnector congestion management. It will be concluded that undertakings put forward by the parties and accepted by the Commission should be restricted to a subsidiary legal instrument, only applied if strictly necessary to overcome certain detrimental aspects of given concentrations in order to provide a hint for the legislator, to specify its legislation. Competition as a de-central distributor of risk, wealth and power will be extended to its maximum extent, if wholesale consumers benefit from lower energy prices which allow greater productivity of European products on the world markets in combination with higher environmental standards owing to modern, cost-efficient plants. A successful implementation will be described by liquid spot markets for power accompanied by tools of financial risk management like forwards, futures and options. These will be valuable indicators of efficient liberalisation of the European electricity and gas supply industries.

This doctoral thesis contains four empirical studies analysing the personal accountability of prime ministers and the electoral presidentialisation of parliamentary elections in European democracies. It develops the concept of presidentialised prime ministerial accountability as a behavioural element in the chain of accountability in parliamentary systems. The ongoing presidentialisation of parliamentary elections, driven by changes in mass communication and erosion of societal cleavages, that fosters an increasing influence of prime ministers’ and other leading candidates’ personalities on vote choices, has called performance voting – and the resulting accountability mechanism of electoral punishment and reward of governing parties – into question. This thesis analyses whether performance voting can be extended to the personal level of parliamentary governments and asks whether voters hold prime ministers personally accountable for the performance of their government. Furthermore, it explores how voters change their opinion of prime ministers and how differences in party system stability and media freedom between Western and Central Eastern Europe contribute to higher electoral presidentialization in Central Eastern European parliamentary elections. This thesis relies on several national data sources: the ‘British Election Study’, the ‘German Longitudinal Election Study’ and other German election surveys, the ‘Danish Election Study’, as well as, data from the ‘Forschungsgruppe Wahlen’. In addition, it utilises cross-national data from the ‘Comparative Study of Electoral Systems’. The findings contribute to the ongoing scholarly debate on the issue of accountability and electoral presidentialisation in parliamentary systems by providing extensive evidence on prime ministerial accountability under presidentialised electoral behaviour. Keywords: presidentialisation; prime ministers; voting behavior; accountability; personalisation.

My dissertation embraces four empirical papers addressing socio-economic issues relevant to policy-makers and society as a whole. These papers cover important aspects of human life including health at birth, life satisfaction, unemployment periods and retirement decisions, and are intended to provide a contribution to the respective research areas. The analyses are carried out applying advanced econometric methods and are based on data sets consisting of survey data as well as administrative records. The joint paper with Alessandro Palma and Daniela Vuri "Prenatal Air Pollution Exposure and Neonatal Health" in Chapter 2 investigates the causal impact of prenatal exposure to air pollution on neonatal health in Italy in the 2000s combining detailed information on mother’s residential location from birth certificates with PM10 concentrations from air pollution monitors. Variation in local weekly rainfall is exploited as an instrumental variable for non-random air pollution exposure. Using quasi-experimental variation in rainfall shocks allows to identify the effect of PM10, ruling out potential bias due to confounder pollutants. The paper estimates the effect of exposure for both the entire pregnancy period and separately for each trimester to test whether the neonatal health effects are driven by pollution exposure during a particular gestation period. This information enhances our understanding of the mechanisms at work and help prevent pregnant mothers from most dangerous exposure periods. Additionally, the effects of prenatal exposure to PM10 are estimated by maternal labor market status and maternal education level to understand how the pollution burden is shared across different population groups. This decomposition allows to identify possible mechanisms through which environmental inequality reinforces the negative impact of early-life exposure to air pollution. This study finds that average PM10 and days with PM10 level above the hazard limit reduce birth weight, gestational age, and measures of overall newborn health. Effects are largest for third trimester exposure and for low-income and less educated mothers. These findings imply that further policy efforts are needed to fully protect fetuses from the adverse effects of air pollution and to mitigate the environmental inequality of health at birth. The joint paper with Christian Pfeifer "Life Satisfaction in Germany After Reunification: Additional Insights on the Pattern of Convergence" in Chapter 3 updates previous findings on the total East-West gap in overall life satisfaction and its trend by using data from the German Socio-Economic Panel for the years 1992 to 2013. Additionally, the effects are separately analyzed for men and women as well as for four birth cohorts. The results indicate that reported life satisfaction is, on average, significantly lower in East than in West German federal states and that part of the raw East-West gap is due to differences in household income and unemployment status. The conditional East-West gap decreased in the first years after the German reunification and remained quite stable and sizable since the mid-nineties. The results further indicate that gender differences are small. Finally, the East-West gap is significantly smaller and shows a trend towards convergence for younger birth cohorts. The joint paper with Christian Pfeifer "Unemployment Benefits Duration and Labor Market Outcomes: Evidence from a Natural Experiment in Germany" in Chapter 4 explores the effects 2 of a major reform of unemployment benefits in Germany on the labor market outcomes of individuals with some health impairment. The reform induced a substantial reduction in the potential duration of regular unemployment benefits for older workers. This work analyzes the reform in a wider framework of institutional interactions, which allows to distinguish between its intended and unintended effects. The results based on routine data collected by the German Statutory Pension Insurance and a Difference-in-Differences design provide causal evidence for a significant decrease in the number of days in unemployment benefits and increase in the number of days in employment. However, they also suggest a significant increase in the number of days in unemployment assistance, granted upon exhaustion of unemployment benefits. Transitions to unemployment assistance represent an unintended effect, limiting the success of a policy change that aims to increase labor supply via reductions in the generosity of the unemployment insurance system. The single-authored paper "How Older Workers Respond to Raised Early Retirement Age: Evidence from a Kink Design in Germany" in Chapter 5 explores how an increase in the early retirement age affects labor force participation of older workers. The analysis is based on a social security reform in Germany, which raised the early retirement age over several birth cohorts to boost employment of older people and ultimately alleviate the burden on the public pension system. Detailed administrative data from the Federal Employment Agency allow to distinguish between employment and unemployment as well as disability pensions and retirement benefits claims. Using a Regression Kink design in a quasi-experimental framework, I show that the raised early retirement age had positive employment effects and negative effects on retirement benefits claims. The reform did not affect unemployment benefits or disability pensions claims. My results also show that some population groups are more sensitive to a reduction in retirement options and more likely to seek benefits from other government programs. In this respect, I find that workers in manufacturing sector respond to the raised early retirement age by claiming benefits from the disability insurance program designed to compensate for reduced earnings capacity due to severe health problems. The treatment heterogeneity analysis further suggests that high-wage workers are more likely to delay exits from employment, which is in line with incentives but might also indicate an increased inequality within the affected birth cohorts induced by the reform. Finally, women seem to rely on alternative sources of income such as retirement benefits for women, or spouse's or partner's income not observed in the data. All things considered, workers did not adjust to the increased early retirement age by substituting early retirement with other government programs but rather responded to the reform in line with the policy intent. At the same time, the findings point to heterogeneous behavioral responses across different population groups. This implies that raising the early retirement age is an effective policy tool to increase employment only among older people who have the real choice to delay employment exits. Therefore, reforms that raise statutory ages should ensure social support for workers only marginally attached to the labor market or not able to work longer due to potential health problems or other circumstances.

In dieser Studie wurde untersucht, ab welcher Größe die statistische Effektstärke Cohen’s d klinisch relevant wird. In einer durch halbstandardisierte Interviews ergänzten Online-Studie wurden den 69 Teilnehmern jeweils vier Szenarien gezeigt, in denen sich Zwillinge in ihren depressiven Beschwerden mit einem d = .5, .8, 1.1 oder 1.4 unterschiedlich stark voneinander unterschieden. Diese Effektstärken wurden durch unterschiedliche Testausprägungen im Depressivitätstest PHQ-9 generiert und lassen sich in Punktunterschiede in den Beschwerdebildern übertragen. Die Beschwerden der Zwillinge wurden jeweils auf Intervallskalen eingeschätzt. Die Zwillinge unterschieden sich zum einen im Ausmaß ihrer Beschwerden, zum anderen entschieden sie sich für unterschiedliche Behandlungsansätze, um Verbesserungen ihrer Beschwerden zu erzielen. Der eine Zwilling wählte eine Psychotherapie, der andere bevorzugte es, zu beobachten und abzuwarten. Eine rmANOVA zeigt, dass die Teilnehmer ab einer Effektstärke von d = .8 verlässlich unterscheiden können, welchem Zwilling es besser geht und in welchem Ausmaß. Diese Effektstärke entspricht einer Punktdifferenz im PHQ-9 von 5 Punkten. Die vorliegende Studie wagt einen ersten Versuch, die klinische Relevanz der Effektstärke Cohen’s d durch subjektive Einschätzungen darzustellen und einen Schwellenwert zu identifizieren. Dieser kann in weiterführender Forschung näher untersucht, optimiert und weiterentwickelt werden.

Due to increased life expectancy, a growing number of retirees are spending more and more time in retirement. Life satisfaction in later life therefore becomes an increasingly important societal issue. Good work ability and health are prerequisites for a self-determined transition to retirement, for example allowing for a continuation of gainful employment beyond retirement age. Such continued employment is one way of dealing with the consequences of a historically unique long retirement phase: a self-determined continued employment can have a positive effect on individual well-being, on societal level relieve the burden on the pension insurance system, and on meso-level provide companies with urgently needed human capital. The self-determination of life circumstances is postulated by Self-Determination Theory (SDT) as a basic psychological need with effects on individual well-being. This dissertation investigates work ability as a concept that supports workers, employers, and societies in the extension of working lives, and how work ability is related to the level of self-determination in the transition to retirement, and ultimately life satisfaction. In the first study of this dissertation, the Work Ability Survey-R (WAS-R) was translated from English into German and then evaluated regarding its psychometric properties and construct validity. The WAS-R operationalizes work ability as the interplay of personal and organizational resources and thus allows companies to derive targeted interventions to maintain work ability. In the second study, the WAS-R was examined together with the questionnaire Work-Related Behavior and Experience Pattern (Arbeitsbezogenes Verhaltens- und Erlebensmuster, AVEM) regarding its construct validity. A striking feature of this study was the high number of participants with the answering pattern indicating low work-related ambitions and protection. Persons with this pattern are in danger of entering the risk pattern for burnout in the future. The findings support the validity of the WAS-R. In the third contribution, two studies examined the experience of control (i.e., autonomy) in the transition to retirement as a mediator between previous work ability, health, and financial well-being, and later life satisfaction in retirement. Control was found to partially mediate the relationship between work ability and later life satisfaction. Different mechanisms on later life satisfaction of work ability and health, and the subjective and objective financial situation were found. This dissertation contributes to research on and practice with aging workers in two ways: (1) The German translation of the WAS-R is presented as a useful instrument for measuring work ability, assessing individual and organizational aspects and therefore enabling employers to make targeted interventions to maintain and improve work ability, and eventually enable control during later work life, the retirement transition and even old age. (2) This dissertation corroborates the importance of good work ability and health, even in old age, as well as control in these phases of life. Work ability is indirectly related to life satisfaction in the long period of retirement, mediated by a sense of control in the transition to retirement. This emphasizes the importance of the need for control as postulated by the SDT also in the transition to retirement.

Die vorliegende Simulationsstudie befasst sich mit der Etablierung und Veränderung der Personal-politik von Organisationen. Das den Simulationsrechnungen zugrunde liegende Modell beschreibt und erklärt den Einfluss personalpolitischer Kraftfelder auf die personalpolitischen Orientierungen von Organisationen. Berücksichtigt werden dabei die Rückwirkungen, die von der Personalpolitik auf die sie bestimmenden Kräfte ausgehen sowie die Beharrungskräfte, die einer einmal etablier-ten personalpolitischen Konstellation innewohnen. Und schließlich wird den Zufallsprozessen, die das personalpolitische Geschehen wesentlich mitbestimmen, die ihnen gebührende Beachtung ge-schenkt. Als theoretische Grundlage dient eine erweiterte und auf die Erklärung der Personalpolitik hin aus-gerichtete Version der Anreiz-Beitrags-Theorie, wonach sich, je nach den gegebenen Feldkraft-konstellationen, angepasste Sozialordnungen herausbilden. Die Elemente und Strukturen dieser Sozialordnungen sind aufeinander abgestimmt und stützen sich gegenseitig. Daraus entwickeln sich interne „Bindungskräfte“, die den verschiedenen Sozialordnungen ihre je eigene Stabilität ver-leihen. Die in dieser Theorie thematisierten Zusammenhänge werden in dem Simulationsmodell konkretisiert und in entsprechende Rechenvorschriften transformiert. Damit wird es möglich, den Ablauf und die Wirkung der von der Theorie unterstellten Mechanismen anhand von konkret be-nennbaren Vorgängen zu analysieren.

Der vorliegende Beitrag untersucht den Zusammenhang zwischen den Big Five Persönlich-keitsfaktoren und vier sozialen Teilfähigkeiten Empathie, Kommunikationsfähigkeiten, Koor-dinationsfähigkeiten und Visionsfähigkeiten gemäß dem Modell der gelingenden Interaktion. Außerdem wird untersucht, inwieweit die sozialen Fähigkeiten und die Big Five Persönlich-keitsfaktoren mit dem Berufs- bzw. dem Führungserfolg korrelieren. Als Datenquellen die-nen zwei Online-Befragungen und das Sozioökonomische Panel. Die in diesen Studien ver-wendeten Kurzskalen werden vorgestellt und die deskriptiven Ergebnisse hierzu werden aus-führlich erläutert. Die Zusammenhangsanalysen bestätigen die Ausgangsvermutung, wonach zwischen den sozialen Fähigkeiten, den Persönlichkeitsfaktoren und dem Berufserfolg zum Teil sehr enge Beziehungen bestehen.

The currently widespread agricultural practices have been increasingly criticised in recent years. They are especially criticised for being unsustainable on an ecological, economic and social level (compare Kalfagianni & Skordili, 2019). Recent developments in the global food system lead to a lack of transparency and unethical practices with negative impacts on human health and the environment from the consumer’s perspective (Wellner & Theuvsen, 2017, p. 235) and to pressure of modernisation and intensification processes from the producer’s perspective. This results in fear for farmers’ existences (Boddenberg et al., 2017, p. 126) and leads to an increased vulnerability of the current food system (Kalfagianni & Skordili, 2019, pp. 3–4). It endangers long-term reliable food provisions and therefore calls for a change of supply and production practices.

When presidents try to expand their tenure in office, are protesting social movements, or even youth movements, able to stop them from candidating unconstitutionally and thus to prevent a democratic backslide? So far, the literature on term bids by presidents tends to focus on the institutional arrangements to hinder such term bids in the first place, on presidential strategies to circumvent the constitutional law, or on counteractions of political elites. Mobilizations against such attempts by presidents to run for office again, after reaching the end of their last allowed term, are often solely included as “pressures from below”. To address these shortcomings, this dissertation explores the issue of term amendment struggles through the lenses of contentious politics systematically combined with insights of revolution theories and democratization studies. Its conceptual perspective therefore lies on the interactions of actors and their constellations to each other as well as to institutions. The author deduces three diverse pathways to promote institutional change and prevent democratic backslidings – through political elites, (political) allies, and security forces. By selecting two cases that are most similar in terms of institutions and youth movements at the forefront, Senegal (2011-12) and Burkina Faso (2013-14), this analysis offers insight in the divergence of the struggles and their outcome. Because in both cases, the announcement of the presidents to run for another term in office led to broad mobilization led by youth movements against such tenure amendments, the political system in general and socioeconomic inequalities - but with diverging results. In Burkina Faso, Blaise Compaoré eventually resigned while Abdoulaye Wade in Senegal candidated again, legitimized by the Constitutional Court. Based on extensive fieldwork, including interviews with movement leaders and their allies, as well as a comprehensive media analysis and the SCAD databank for the analysis of protest events, the author differentiates and reconstructs the various phases of the conflict. The results of the dissertation point at two dimensions most relevant to comprehend the dissimilar pathways the struggles took – the reach of mobilization and, closely interlinked to the first, the refusal of soldiers to obey orders. It shows further that these differences go back to the respective history of each country, its former protest waves, and political culture. Although both presidents faced mass mobilization against their unconstitutional candidature, only in Burkina Faso it eventually led to an ungovernable situation. The dissertation concludes by reflecting on lessons learned for future democratic backslidings by presidents to come and avenues for future research – and thus offers fruitful insights not only for academics but for those who aim to save democratic norms and institutions.

Der vorliegende Beitrag befasst sich mit Typisierungen der Personalpolitik, die sich darauf rich-ten, charakteristische Muster der Personalpolitik zu identifizieren und deren Zustandekom-men zu erklären. Beschrieben werden der Erkenntniswert, der typologischen Ansätzen zu-kommt, und die Schwierigkeiten, die sich der Identifikation personalpolitischer Muster entge-genstellen. Ungeachtet der sich dabei stellenden Probleme erscheint es wünschenswert und möglich, über lediglich intuitiv plausible Ansätze hinauszugehen und theoretisch gut veran-kerte Typologien zu entwickeln. Einen breiten Raum nimmt im vorliegenden Beitrag die Darstellung der in der Literatur vor-findlichen Typisierungen der Personalpolitik ein. Zu unterscheiden ist hierbei zwischen Typo-logien, die sich auf das Gesamtsystem Organisation und Typologien, die sich, im engeren Sinne, auf einzelne Funktionsbereiche des Personalwesens beziehen. Das Spektrum der den Typisierungen zugrundeliegenden theoretischen Überlegungen erweist sich zwar als sehr breit, es wird aber dennoch von einigen wenigen Grundthemen bestimmt. Auch schließen sich die Typisierungen nicht gegenseitig aus, sie beleuchten oft einfach unterschiedliche Aspekte der Personalpolitik. Der Gedanke, dass sich verschiedenartige personalpolitische Ausrichtun-gen ergänzen und in ihrer Wirkung verstärken können, wird im Konzept der „Sozio-Bricks“ aufgenommen und vertieft. Hierauf wird gesondert eingegangen. Danach werden die Erfahrungen aus einer Reihe von empirischen Erkundungen beschrieben, die darauf abzielten, das komplexe Untersuchungsobjekt Personalpolitik näher zu charakteri-sieren und anschaulich zu machen. Als theoretische Referenz diente das Sozio-Bricks-Konzept und es wurde geprüft, ob sich mit dessen Hilfe stimmige, in der betrieblichen Realität vorfind-liche, personalpolitische Muster identifizieren lassen. Abschließend wird mit der Simulationsmethode noch ein Ansatz theoretischer Erkundungsar-beit skizziert. Der große Vorteil von Simulationsmodellen besteht darin, dass sie dazu zwingen, die Mechanismen zu operationalisieren, die man dafür verantwortlich macht, dass sich be-stimmte personalpolitische Muster herausbilden. Außerdem erlauben entsprechend konzi-pierte Modelle, den Wirkungsverbund der auf die Personalpolitik einwirkenden Kräfte zu un-tersuchen.

To improve the properties of thermochemical heat storage materials, salt mixtures were evaluated for their heat storage capacity and cycle stability as part of the innovation incubator project “Thermochemical battery” of the Leuphana university Lüneburg. Based on naturally occurring compound minerals, 16 sulfates, 18 chlorides and 5 chloride multi-mixtures, 18 bromides and 5 intermixtures between sulfates, chlorides and bromides were synthesized either from liquid solution or by dry mixing for TGA/DSC screening before continuing the heat storage evaluation with five different measurement setups at a laboratory scale. The TGA/DSC analysis served as a screening process to reduce the number of testing materials for the upscaled experiments. The evaluation process consisted of a three-cycle dehydration/hydration measurement at Tmax = 100°C and Tmax = 200°C. In case of the bromide samples a measurement of hydration conditions with Tmax = 110°C and a water flow at e = 18.68mbar, were added to the procedure to detect the maximum water uptake temperature. Also, a single dehydration to a temperature of Tmax = 500°C was implemented to observe melting behavior and to easier calculate the samples’ stages of hydration from the remaining anhydrous mass. Materials which showed high energy storage density and improved cycle stability during this first evaluation were cleared for multi-cycle measurements of 10 to 25 dehydration and hydration cycles at Tmax = 100 to 120°C and the evaluations at m = 20 to 100g scale. An estimate for the specific heat capacities at different temperatures of the materials which passed the initial stage was calculated from the TGA/DSC results as well. The laboratory scale measurement setup went through five stages of refining, which led to reducing the intended maximum sample mass from m = 100g to m = 20g. A switch from supplied liquid water to water vapor as the used reactant was also implemented in exchange for improved dehydration conditions. Introducing a vacuum pump for evaporating the water limited the influence of outside heat sources during hydration and in-situ dehydration was enabled as to not disturb the state the samples were settling in between measurements. Baseline calculation from blanc measurements with glass powder and attempts to calculate the specific heat capacity cp of the tested materials by 6 applying the Joule-Lenz-law to the measurement apparatus was another step of method development. The evaluation process of the laboratory scale tests at the final setting consisted of 1 to 5 cycle measurements of in-situ dehydration and hydrations with applied vacuum for t = 30 minutes at p ~ 30mbar. Upscaling the sample mass to m = 20g allowed for a close observation of different material behaviors. Agglomeration, melting and dissolving of the m = 10mg samples during the TGA/DSC analysis can be deducted from the recorded measurement curves and the state of the sample after measurement. However, at laboratory scale the visible volume changes, observed sample consistency after agglomeration and an automatic removal of molten and dissolved sample mass during the measurement allowed for a better characterization and understanding of the magnitude of the actual changes. This was done for the first time, particularly for mixed salts. Of the original number of 62 samples, 4 mixtures which passed the initial TGA/DSC screening namely {2MgCl2+ KCl}, {2MgCl2+CaCl2}, {5SrBr2+8CaCl2} and {2ZnCl2 + CaCl2} were chosen for further evaluation. The multi-cycle TGA/DSC measurements of {2MgCl2+ KCl}, {2MgCl2+CaCl2} and {5SrBr2+8CaCl2} showed an improved cycle stability for all three materials over the untreated educts. Of the four materials {2ZnCl2 + CaCl2} displayed the strongest deliquescence during hydration in the upscaled experimental setup. {2MgCl2+CaCl2} proved to be the most stable material regarding the heat storage density. The {MgCl2} content of the mixture is likely to partially or completely react to {Mg(OH)Cl} at temperatures of T > 110°C, which however does not impede the heat storage density. {5SrBr2+8CaCl2} displayed a low melting point in hydrated state, causing a fast material loss. This makes it an undesirable storage material. A lower heating rate may still help to avoid an early melting. The {2MgCl2+KCl} mixture was the most temperature stable of the mixtures showing no melting or dissolving behavior. A reaction of the {MgCl2} component of the mixture to {Mg(OH)Cl} was not observed within the applied temperature range of T = 25 to 200°C.

Empirische Studien aus dem Bereich der Lehrerbildungsforschung haben gezeigt, dass die Arbeit mit Unterrichtsvideos eine wirksame Möglichkeit darstellt, um professionelle Kompetenzen von Lehramtsstudierenden zu erweitern. In der Unterrichtsforschung werden Unterrichtsvideos darüber hinaus auch als Messinstrument zur Wahrnehmung von Unterrichtsqualität genutzt. Dabei werden meist Filmaufnahmen verwendet, die mit einer Überblicks- oder Lehrerkamera gefilmt wurden. In diesem Kontext äußern Bildungswissenschaftlerinnen und Bildungswissenschaftler die Annahme, dass die gefilmte Kameraperspektive einen Effekt auf die Beobachtung und Beurteilung der Unterrichtsvideos haben kann. Empirische Befunde sind zu dieser Hypothese bisher wenig vorhanden. Die vorliegende Dissertation hat sich daher - in der Tradition standardisierter Videostudien - das Ziel gesetzt, das bisherige standardisierte Kamerasetting inhaltlich-konzeptionell durch die Installierung mehrerer Schülerkameraperspektiven weiterzuentwickeln. Auf dieser Grundlage wurde geprüft, ob die Raterinnen und Rater durch den Einsatz multiperspektivischer Videos in ihrer Einschätzung der Unterrichtsqualität zu unterschiedlichen Ergebnissen gelangen. Die Befunde belegen, dass Raterinnen und Rater ein Unterrichtsgeschehen mit den etablierten Perspektiven der Überblicks- oder Lehrerkamera nahezu ähnlich einschätzen. Mit weiteren Kameraperspektiven, die auf die Schülerinnen und Schüler gerichtet sind, wird jedoch eine deutlich breitere Beurteilung in den Dimensionen „Kognitive Aktivierung“, „Klassenmanagement“ und „Individuelle Förderung“ deutlich. Mehrere Kameraperspektiven ermöglichen detaillierte Aussagen über Unterricht - von diesem Ergebnis können auch Studierende in der Lehrpersonenausbildung profitieren. Schülerkameraperspektiven eröffnen Dozierenden insbesondere zur Thematik „heterogene Schülerschaft“ ein didaktisches Lehrmittel und Werkzeug, das eine Videoanalyse zu Mikrointeraktionen zwischen Schülerinnen und Schülern-Lehrpersonen-Interaktionen dynamisch und simultan erlaubt. Die befragten Studierenden dieser Arbeit gaben an, gern in weiteren Lehrveranstaltungen mit mehrperspektivischen Unterrichtsvideos zu arbeiten.

Mobilität und Tourismus gehören untrennbar zusammen, denn ohne einen Ortswechsel gibt es keine Urlaubsreise. Der Tourismus aber verursacht ca. 5 % der anthropogenen Kohlendioxidemissionen, von denen etwa 75% auf den touristischen Verkehr entfallen. Neben dem Flugverkehr trägt insbesondere der motorisierte Individualverkehr einen hohen Anteil an den Emissionen. Angesichts des deutlichen Beitrags des touristischen Verkehrs zum Klimawandel erscheint es notwendig, sich mit Wegen zu einer ökologischen touristischen Mobilität zu beschäftigen. Zur Untersuchung der Einflussfaktoren auf die touristische Verkehrsmittelwahl wurde ein Erklärungsmodell basierend auf der Theorie des geplanten Verhaltens entwickelt. Neben den Basiskonstrukten der Einstellung, der subjektiven Norm und der wahrgenommenen Verhaltenskontrolle wurden als ergänzende Modellkonstrukte die persönliche Norm, das allgemeine Umweltbewusstsein sowie gewohnheitsmäßiges Handeln hinzugefügt. Eine empirische Untersuchung mit n=738 ermittelte durch multiple lineare Regression wichtige Ansatzpunkte für die Gestaltung von Handlungsempfehlungen. Signifikante Ergebnisse konnten für die Konstrukte der Einstellung, der subjektiven Norm, der wahrgenommenen Verhaltenskontrolle, der persönlichen Norm, der Gewohnheit sowie der Kontrollvariablen Alter und Einkommen erreicht werden. An diesen Einflussfaktoren auf die Intention, zukünftig ein umweltfreundlicheres Verkehrsmittel zur Reise in den nächsten Städte-Kurzurlaub zu wählen, setzen die Implikationen für die Praxis an und zeigen Möglichkeiten auf, die touristische Mobilität ökologischer zu gestalten.

Ziel der Studie ist es die Determinanten für das Komforterleben bzw. die Zufriedenheit in der Flugzeugkabine zu identifizieren. Wenige empirische Modelle zum Flugzeugkabinenkomfort gibt es und vereinzelt werden Umgebungsfaktoren wie Akustik, Turbulenzen, Temperatur und Luftqualität untersucht, aber kein Vorhersagemodell für den Gesamtkomfort existiert bislang. Ein Methodenmix aus drei Datenerhebungen wird angewendet: 1. In der ersten Untersuchung werden zehn Flugzeugkabinenbilderpaare zehn Sekunden pro Bild präsentiert. Über die multidimensionale Skalierung wird auf einer fünfstufigen Skala die Ähnlichkeit von sehr bis gar nicht dargeboten. Die eindimensionale Darstellung der Bilder legt nahe, dass es einen Faktor wie „Platz zum Sitzen“ gibt. In Interviews wird der Annahme nachgegangen. 2. In Interviews assoziierten 61 Psychologiestudierende Nomina zum Fliegen. Bei den Kategorien stellt Platz/ Beinfreiheit der am häufigsten genannte Komfortaspekt innerhalb einer Flugzeugkabine dar. Sitzkomfort, Flugbegleiter, Inflight-Entertainment, Essen, Trinken, Sicherheit, Sauberkeit wurden oft genannt und Temperatur, Design, Toiletten, Geräusche, Turbulenzen, Geruch, Luftqualität, Beleuchtung, Raucherbereiche, ein gutes Preis-Leistungsverhältnis nur vereinzelt. 3. Die Fragebögen am Hamburger Flughafen greifen die in den Interviews genannten Komfortaspekte auf. 301 Passagiere beantworteten Zufriedenheitsitems auf einer fünfstufigen Skala. Mittels einer explorativen Faktorenanalyse werden fünf Faktoren aus den Items extrahiert, die räumliche, physiologische, psychologische, physikalische und organisatorische Aspekte beinhalten. Eine lineare multiple Regression mit den fünf Faktoren zum Item „Gesamtzufriedenheit“ ist hochsignifikant und klärt 40,5 %t Varianz auf. Die Moderatoreinflüsse und Interaktionen werden teils signifikant und klären 1,6 % weniger (Fluglänge) oder 1,5 % mehr (Fluggesellschatt und -angst) Varianz auf. Mittelwertsvergleiche zeigen, dass die Star Alliance Fliegenden und nicht Flugängstlichen bei allen fünf Faktoren und fast allen Items hochsignifikant höhere Zufriedenheitswerte als Billigfliegende und Flugängstliche aufweisen. Bei Kurz- über Mittel- zum Langstreckenflug wurde eine v-Form gefunden mit der geringsten Zufriedenheit bei Mittelstreckenflügen mit hochsignifikanten Unterschieden. Entscheidend ist das durch die Kombination aus Zusammenhangs- und Vorhersageanalyse für den Forschungsbereich „Komfort in der Flugzeugkabine“ neu generierte Gesamtkomfortmodell.

Both sustainability and transdisciplinary research can change academic research, especially with regard to its relevance for, and relationship with, its environments. Transdisciplinary sustainability research (TSR), thus, offers the opportunity to change non-sustainable development paths of sciences themselves. In order to fully exploit this possibility, this PhD project addresses the question of how TSR, in the first place, does conceptualize and, in the second place, could conceptualize knowledge, research, and science. Firstly, this PhD project analyzes, from a discourse studies perspective, the term problem in TSR, against the background of discourses on sustainable development. Secondly, it explores the historicalanalytical and transformative concept of the problematic. The results, firstly, show the consequences of a problem-solving focus for TSR, and secondly, differentiate it from a transformative direction of problematic designing, as a more appropriate view on the dimensions of transformation and their qualities of change that matter for TSR. This PhD project aims to contribute to a self-understanding of, and a philosophical communication about, TSR, as a research form in the sustainability sciences. Keywords: Discourse studies, problem-solving, transdisciplinary sustainability research, transformative potential, dimensions of transformation.

The geographical situation of Germany considerably affects the final energy consumption of the country. Thermally intensive processes are the largest consumer of energy. In contrary, the level of energy consumed by air conditioning systems and utilized on process cooling is relatively low. Thermal energy storage systems have a high potential for a sustainable energy management, as they provide an efficient integration of thermal energy from renewables and heat recovery processes through spatial and temporal decoupling. Low temperature thermochemical energy stores based on gas-solid reactions represent appealing alternative options to sensible and latent storage technologies, in particular for heating and cooling purposes. They convert heat energy provided from renewable energy and waste heat sources into chemical energy and can effectively contribute to load balancing and CO2 mitigation. Reasonable material intrinsic energy storage density and cooling power are demanded. At present, several obstacles are associated with the implementation in full-scale reactors. Notably, the mass and heat transfer must be optimized. Limitations in the heat transport and diffusions resistances are mainly related to physical stability issues, adsorption/desorption hysteresis and volume expansion and can impact the reversibility of gas-solid reactions. The aim of this thesis was to examine the energy storage and cooling efficiency of CaCl2, MgCl2, and their physical salt mixtures as adsorbents paired with water, ethanol and methanol as adsorbates for utilization in a closed, low level energy store. Two-component composite adsorbents were engineered using a representative set of different host matrices (activated carbon, binderless zeolite NaX, expanded natural graphite, expanded vermiculite, natural clinoptiolite, and silica gel). The energetic characteristics and sorption behavior of the parent salts and modified thermochemical materials were analyzed employing TGA/DSC, TG-MS, Raman spectroscopy, and XRD. Successive discharging/charging cycles were conducted to determine the cycle stability of the storage materials. The overall performance was strongly dependent on the material combination. Increase in the partial pressure of the adsorbate accelerated the overall adsorbate uptake. From energetic perspectives the CaCl2-H2O system exhibited higher energy storage densities than the CaCl2 and MgCl2 alcoholates studied. The latter were prone to irreversible decomposition. Ethyl chloride formation was observed for MgCl2 at room and elevated temperatures. TG-MS measurements confirmed the evolution of alkyl chloride from MgCl2 ethanolates and methanolates upon heating. However, CaCl2 and its ethanolates and methanolates proved reversible and cyclable in the temperature range between 25 °C and 500 °C. All composite adsorbents achieved intermediate energy storage densities between the salt and the matrix. The use of carbonaceous matrices had a heat and mass transfer promoting effect on the reaction system CaCl2-H2O. Expanded graphite affected only moderately the adsorption/desorption of methanol onto CaCl2. CaCl2 dispersed inside zeolite 13X showed excellent adsorption kinetics towards ethanol. However, main drawback of the molecular sieve used as supporting structure was the apparent high charging temperature. Despite variations in the reactivity over thermal cycling caused by structural deterioration, composite adsorbents based on CaCl2 have a good potential as thermochemical energy storage materials for heating and cooling applications. Further research is required so that the storage media tested can meet all necessary technical requirements.

The world currently faces important issues concerning climate change and environmental sustainability, with the wellbeing of billions of people around the world at risk over the next decades. Existing institutions no longer appear to be sufficiently capable to deal with the complexity and uncertainty associated with the wicked problem of sustainability. Achieving the required sustainability transformation will thus require purposeful reform of existing institutional frameworks. However, existing research on the governance of sustainability of sustainability transformations has strongly focused on innovation and the more ‘creative’ aspects of these processes, blinding our view to the fact that they go hand with the failure, decline or dismantling of institutions that are no longer considered functional or desirable. This doctoral dissertation thus seeks to better understand how institutional failure and decline can contribute productively to sustainability transformations and how such dynamics in institutional arrangements can serve to restructure existing institutional systems. A systematic review of the conceptual literature served to provide a concise synthesis of the research on ‘failure’ and ‘decline’ in the institutional literature, providing important first insights into their potentially productive functions. This was followed up by an archetype analysis of the productive functions of failure and decline, drawing on a wide range of literatures. This research identified five archetypical pathways: (1) crises triggering institutional adaptations toward sustainability, (2) systematic learning from failure and breakdown, (3) the purposeful destabilisation of unsustainable institutions, (4) making a virtue of inevitable decline, and (5) active and reflective decision making in the face of decline instead of leaving it to chance. Empirical case studies looking at the German energy transition and efforts to phase out coal in the Powering Past Coal Alliance served to provide more insights on (a) how to effectively harness ‘windows of opportunity’ for change, and (b) the governance mechanisms used by governments to actively remove institutions. Results indicate that the lock-in of existing technologies, regulations and practices can throw up important obstacles for sustainability transformations. The intentional or unintentional destabilisation of the status quo may thus be required to enable healthy renewal within a system. This process required active and reflective management to avoid the irreversible loss of desirable institutional elements. Instruments such as ‘sunset clauses’ and ‘experimental legislation’ may serve as important tools to learn through ‘trial and error’, whilst limiting the possible damage done by failure. Focusing on the subject of scale, this analysis finds that the level at which failure occurs is likely to determine the degree of change that can be achieved. Failures at the policy-level are most likely to merely lead to changes to the tools and instruments used by policy makers. This research thus suggests that failures on the polity- and political level may be required to achieve transformative changes to existing power structures, belief-systems and paradigms. Finally, this research briefly touches on the role of actor and agency in the governance of sustainabilitytransformations through failure and decline. It finds that actors may play an important role in causing a system or one of its elements to fail and in shaping the way events are come to be perceived. Drawing on the findings of this research, this dissertation suggests a number of lessons policy makers and others seeking to revisit existing institutional arrangements may want to take into account. Actors should be prepared to harness the potential associated with failure and decline, preserve those institutional elements considered important, and take care to manage the tension between the need for ‘quick fixes’ to currently pressing problems and solution that maintain and protect the longterm sustainability of a system.

Die Energiewende steht im Zentrum aktueller gesellschaftlicher Debatten. Die Frage ist: Wie kann die gegenwärtige Klimakrise aufgehalten und gleichzeitig der Energiebedarf gedeckt werden? Einigkeit besteht darüber, dass eine Strategie zur Energiewende die Umstellung auf erneuerbare Energieträger beinhalten muss. Das Problem ist: Zentrale Begriffe wie ‚erneuerbare Energieträger‘ sind uneindeutig und deshalb besonders für naturwissenschaftliche Laien missverständlich. Ihnen wird dadurch die gesellschaftliche Teilhabe an der Debatte erschwert. Wie kann der naturwissenschaftliche Unterricht dazu beitragen, die oben benannten Missverständnisse aufzuklären? Er muss die Schüler*innen dabei unterstützen, die naturwissenschaftlichen Schlüsselprinzipien der verschiedenen Energieträger und darauf aufbauend die Energiewende angemessen zu verstehen. Zu diesem Zweck muss der Unterricht entsprechend strukturiert werden. Welche Leitlinien sowohl die Lehrkräfte der Naturwissenschaften als auch die Entwickler*innen der Unterrichtsmaterialien dabei beachten sollten: Das klärt die vorliegende Studie. Hierfür wird das Modell der didaktischen Rekonstruktion als Forschungsrahmen genutzt. Ausgehend von einem gemäßigt konstruktivistischen Lehr-Lernverständnis werden drei Unterfragen beantwortet: 1. Welche vorunterrichtlichen Vorstellungen bringen Schüler*innen in den Unterricht mit? 2. Welche Vorstellungen haben Wissenschaftler*innen? 3. Welche Unterschiede ergeben sich im Vergleich der Vorstellungen? Für die Beantwortung dieser Fragen wurden in der Erhebung problemzentrierte, leitfadengestützte Interviews mit 27 Achtklässler*innen geführt und Auszüge aus zwei wissenschaftlichen Gutachten ausgewählt. Mit einer qualitativen Inhaltsanalyse konnten in der Auswertung Inhaltsaspekte identifiziert werden, die Potenzial für die unterrichtliche Vermittlung haben. Mit dem so reduzierten Datenmaterial wurde eine systematische Metaphernanalyse durchgeführt. Damit wurden erfahrungsbasierte Muster hinter den Vorstellungen rekonstruiert. Aus dem systematischen Vergleich der Ergebnisse lassen sich Lernchancen und Lernhindernisse für das Verstehen von naturwissenschaftlichen Hintergründen der Energiewende ableiten. Diese werden in Form von Leitlinien für den naturwissenschaftlichen Unterricht zusammengefasst. Diese Leitlinien können von Lehrpersonen und Entwickler*innen von Lehrmaterialien genutzt werden, um ein fachlich angemessenes Verstehen der naturwissenschaftlichen Schlüsselprinzipien der Energieträger und der Energiewende zu fördern. Darüber hinaus sind diese Ergebnisse interessant für Forschende, die an der Energiewende und deren wissenschaftlicher Kommunikation interessiert sind. Denn sie helfen zu verstehen, wie Missverständnisse vermieden und fachliche Begriffe geklärt werden können.

The dissertation contains four journal articles which are embedded within a framework manuscript that interconnects the individual articles and provides relevant background information. The dissertation’s overall objective is to provide a multilayered and critical in-depth engagement with the timely phenomenon of integrated reporting (IR), a new reporting concept that is envisaged to revolutionize firms’ present reporting infrastructure. While extant corporate reports (e.g., annual financial- and CSR report) often are criticized for being disconnected and to suffer from a lack of coherence, IR intends to provide all information that is material to a firm’s short-, medium- und long-term value creation within one single, succinct document. To contribute to a set of previously defined relevant research gaps in literature, the dissertation makes use of a combined empirical-quantitative and explorative-qualitative research design. The first article entitled ‘Determinants of materiality disclosure quality in integrated reporting: Empirical evidence from an international setting’ investigates a set of different IR-, corporate governance and financial accounting-specific factors that are expected to determine European and South African firms’ materiality disclosure quality. To this purpose, an original, hand-collected materiality disclosure score was developed. The second article ‘Managers’ incentives and disincentives to engage with integrated reporting, or why managers might not adopt integrated reporting: an exploratory study in a nascent setting‘ explores IR perceptions of SME managers that have not embarked on IR, but are potential candidates to do so in future. Based on a review of extant literature, the article develops a theoretical framework to subsequently discuss motives for and barriers to IR adoption. The critical discussion contributes to the academic debate on incentives for and barriers to voluntary IR adoption. The third article named ‘Does it pay off? Integrated reporting and cost of debt: European evidence’ investigates whether voluntary IR adoption among European firms is associated with lower cost of public debt. While earlier studies suggest that IR leads to lower information asymmetries, increases analyst forecasts, and decreases cost of equity, corresponding evidence for the debt market is largely missing. Subsequent analyses test as to whether such an association is even more pronounced by a firm’s environmental, social and governance (ESG) performance or its belonging to an environmentally sensitive industry. The fourth article ‘Do nonprofessional investors value the assurance of integrated reports? Exploratory evidence’ uses an experimental design to investigate nonprofessional investors’ reactions to an IR assurance. To this purpose, two separate experiments with two different groups of nonprofessional investors were carried out: one with Masters students and one with managers of large corporations. Results help to answer the question as to whether an IR assurance as well as its determinants, namely the assurance provider and the assurance level, affect nonprofessional investors’ financial decision-making. In the second step, subsequent in-depth interviews reveal an IR assurance-critical attitude among managers, who draw upon their practical experience with assurance engagements.

Die vorliegende Arbeit untersucht das Reiseverhalten verschiedener Generationen in Deutschland (68er, Babyboomer, Generation X und Generation Y) anhand der Kohortenanalyse. Mit Hilfe des Intrinsic Estimators und der Rohdaten der Reiseanalyse für die Jahre 1971 bis 2012 wurden Kohorten-, Alters- und Periodeneffekte für die verschiedenen Merkmale des Reiseverhaltens geschätzt. Deutliche Unterschiede zwischen den Generationen, die unabhängig von Alter und Jahr bestand haben sollten, wurden in Bezug auf die Wahl des Verkehrsträgers, der Unterkunft, der Reiseart und der Destination identifiziert. Bei anderen Merkmalen gab es hingegen weniger oder nur geringe Generationenunterschiede. Die Ergebnisse ermöglichen einen genaueren Blick in die Zukunft des Reisens und geben wichtige Hinweise für die tourismuswirtschaftliche Praxis.

The present doctoral dissertations seeks to shed theoretical and empirical light on how complexity and different approaches to manage it affect perceptions, behaviors, and outcomes in integrative negotiations. Chapter 1 summarizes the following five chapters, describes their individual contribution to the present thesis, and outlines avenues for future research. In Chapter 2, a theoretical model comprising of task- and context-based determinants of complexity in negotiations is developed. In Chapter 3, the effects of the number of issues (high vs. low) as one essential determinant of complexity on parties’ trade-off behavior and joint outcomes are investigated in a series of four experiments. Furthermore, negotiators’ cognitive categorizing of issues (i.e., their mental-accounting approach) is examined as the underlying psychological mechanism. Results reveal that more issues lead to a higher risk of scattering the integrative potential between cognitive categories (i.e., mental accounts), reducing trade-off quality and joint outcomes. In Chapter 4, the generalizability of the detrimental effect of the number of issues on joint outcomes is tested across varying numbers of issues in a meta-analysis. Moreover, boundary conditions for the effect are investigated. Results confirm the generalizability of the number-of-issues effect, but no relevant boundary conditions are identified. In Chapter 5, the effects of different mental-accounting approaches on negotiators’ judgment accuracy, trade-off behaviors, and negotiation outcomes are examined in a series of five experiments. Results demonstrate that categorizing a moderate number of issues into each mental account leads to a higher judgment accuracy, trade-off quality, and joint outcomes, but only if negotiators manage to pool the integrative potential within these accounts. Finally, Chapter 6 takes a broader perspective on different integrative strategies in negotiations (i.e., expanding the pie, logrolling, solving underlying interests), thereby laying the groundwork for future research. Keywords: integrative negotiation, complexity, number of issues, mental accounting

Decoding the psychological dimensions of human odor perception has long been a central issue of olfactory research. As odor percepts could not be linked to a few measurable physicochemical features of odorous compounds or physiological characteristics of the olfactory system, odor qualities have often been assessed by perception–based ratings. Although these approaches have been promising, none of the proposed system has sustained empirical validation. In a review of 28 studies, we assessed how basic characteristics of study design have been biasing perception–based classification systems: (1) interindividual differences in perceptual and verbal abilities of subjects, (2) stimuli characteristics, (3) approaches of data collection, and (4) methods of data analysis. Remarkably, many of the difficulties in establishing these systems have been rooted in one underlying issue: the puzzling relationship between language and olfaction in general. While the reference from odors to language is weak, the reverse impact of verbal processing on olfaction seems powerful. Odor perception is biased by verbal–semantic processes when cues of an odor’s source are readily available from the context. At the same time, olfaction has been characterized as basically sensation driven when this information is absent. We examined whether language effects occur when verbal cues are absent and how expectations about an odor’s identity shape odor evaluations. Subjects were asked to rate 20 unlabeled odor samples on perceptual dimensions as well as quality attributes and to eventually provide an odor source name. In a subsequent session, they performed the same rating tasks on a set of written odor labels that was compiled individually for each participant. It included both the 20 correct odor names (true labels) and – in any case of incorrect odor naming in the first session – the self–generated labels (identified labels). We compared odor ratings to ratings of both types of labels and found higher consistencies between the evaluation of an odor and its identified label than between the description of an odor and its true (yet not associated) label. These results indicate that basic perceptual as well as quality ratings are affected by semantic information about an odor’s source – even in absence of source cues. That is, odor sensation may activate a semantic mental representation of an odorous object that affects odor processing and may in turn relate to further multimodal properties. That means, associations between odors and stimuli from other sensory modalities should not only be stable, but these mappings should be mediated by an odor’s identity. We asked subjects to visualize their odor associations on a drawing tablet, freely deciding on color and shape. Additionally, they provided a verbal label for each sample. Color mappings were odor-specific, they reflected the imagery of a natural source and seemed to change with assumed odor identity. Shape mappings changed with odor identifications as well, as drawings frequently displayed concrete objects that reflected visual features of an odor’s source. The influence of verbal identity codes on quality ratings or crossmodal mappings is rooted in the very same problem that perception–based classification systems have tried to solve – a terminology that relates to abstract mental categories. The less specific we communicate, the more we need to resort to source–related analogies – in scientific endeavors and everyday life alike.

Forest ecosystems significantly contribute to global carbon (C) sequestration and therefore play a crucial role for climate change mitigation. At the same time, forests were and are subjected to past and current environmental changes with consequences for the functioning of forest ecosystems and their associated ecosystem services. Forests in Central Europe are highly influenced by former settlement activities and land-use changes, as well as silvicultural management measures. Until the beginning of the 19th century anthropogenic activities caused a tremendous decline of the forest area. The resulting timber shortage led to large scale afforestations on previously agriculturally used land (e.g. heathlands, grasslands and croplands) during the 19th and 20th century. Widespread afforestation programs created recent forest ecosystems (i.e. young forest systems in terms of their development history). Despite the positive effect of increasing the forest area of Central Europe, the ecological effects of these land-use changes on forest ecosystems remain poorly understood. In addition, most forests in Central Europe are under silvicultural management, while the knowledge about the consequences of management measures on forest ecosystem functioning, particularly in the face of ongoing global environmental changes, is also still limited. In order to increase the understanding of ecosystem processes in forests, an assessment of conceivable shifts in ecosystem functions caused by former land-use changes and forest management is required. By analysing aboveground growth rates of European beech (Fagus sylvatica L.) in response to environmental change drivers, such as climate extremes and nitrogen (N) deposition, the presented thesis aims to assess the role of land-use and management legacies in modulating present responses to drivers of environmental change. To this end, annual radial growth rates of individual trees were measured in mature beech stands. The investigated stands differed either in their land-use history (i.e. ancient forest sites with a forest continuity > 230 years versus recent forests afforested on former arable land ~ 100 years ago) or their forest management history (i.e. managed forest sites versus short-term and long-term unmanaged forest sites). Measurements of radial growth rates were complemented by analyses of the fine root systems, soil chemical properties and crown projection areas to gain insights into the mechanisms underlying alterations in tree growth. Within the projects of the presented thesis, shifts in the climate-growth relationships driven by land-use and management legacies were analysed. In addition, land-use legacy mediated differences in the climate-nitrogen-growth relationships were assessed. The key findings are: (I) Soil legacy driven alterations in the fine root systems cause a higher sensitivity of radial increment rates to water deficits in summer for trees growing on recent forest sites than for trees growing on ancient forest sites. (II) Management legacies (in terms of tree release) enhance the sensitivity of beech’s radial growth to water deficits in spring through changes in crown sizes. (III) Interacting effects of spring water deficits and co-occurring high deposition of reactive N compounds lead to stronger radial growth declines in trees growing in ancient forests. This is likely caused by resource allocation processes towards seed production, which is, in turn, mirrored by decreasing radial growth rates. In this context, high N deposition likely boosts mass fructification in beech trees. Overall, it has been demonstrated that the ecological continuity plays a crucial role in modulating both climate sensitivity and the growth response to interacting effects of water deficits and nitrogen deposition in beech trees. The presented thesis identified a trade-off between the climate sensitivity and maximised growth rates within beech trees, depending on forest history. The results show that the growth of beech in ancient, unmanaged beech forests is less sensitive to water deficits than in recent and managed beech forests. Additionally, interacting effects of spring water deficits and N deposition likely increase the reproductive effort of beech trees, particularly in ancient forests. Thus, the results of this thesis once again underpin the uniqueness of ancient, unmanaged beech forests, whose importance for the conservation of biodiversity has been widely acknowledged. In summary, the presented thesis highlights the need to consider the ‘ecological memory’ of forest ecosystems when predicting responses to current and future environmental changes.

This doctoral research is located in the branch of sustainability sciences that has the realisation of sustainable development as its core subject of research. The most broadly accepted notion of sustainable development is that which evolves along the resolutions, declarations, and reports from international processes in the framework of the United Nations (UN). The consensual outputs from such processes feature global-generalised and context-free perspectives. However, implementation requires action at diverse and context-rich local levels as well. Moreover, while in such UN processes national states are the only contractual parties, it is increasingly recognised that other (‘nonstate’) actors are crucial to sustainability. The research presented here places the attention on bottom-up initiatives that are advancing innovative ways to tackle universal access to clean energy and to strengthen small-scale family farmers. This means, the focus is on bottom-up initiatives advancing local implementation of global sustainability targets, more precisely, targets that make part of the Sustainable Development Goals two and seven (SDG 2 and SDG7). The research asks how such bottom-up initiatives can contribute to the diffusion of sustainability innovations, thereby also contributing to social change. Three aims are derived out of that central question: • Analytical: To understand the role of bottom-up initiatives in the diffusion of sustainability innovations and in the thereby involved social changes. • Transformative: To contribute with my research to the actual diffusion of sustainability innovations. • Methodological: To outline a research approach that provides a solid conceptual and methodological framework for attaining the analytical and transformative aims. Conceptually, the research builds on theoretical insights from diverse strands of the broad field of sustainability transitions – mostly on conceptualisations from transition management, strategic niche management, and grassroots innovations – as well as on conceptual and methodological advances in transdisciplinary and in transformative research. The doctoral research comprises four single studies, in which the notion of diffusion is explored at different scopes of social scales. It begins with a thorough analysis of diffusion programs of domestic biodigesters to rural households in countries of the global south. The focus is on the process by which this specific technical inno0vation results integrated (or not) into the daily realities of single rural households, that is, the adoption process. In the second study, the attention is on energy supply models based on different decentralised renewable technologies. Central to these models is the building of new (or strengthening of existing) local socioeconomic structures that can assume and ensure the proper operation and supply of energy services. The interest in this study is on the strategies that organisations implementing community-based energy projects apply to support the realisation of such local structures. The third study focuses on a network of bottom-up initiatives that have been advancing alternative approaches to family farming in Colombia. The network mainly comprises farmers associations, other organisations from civil society, and researchers who had been collaborating and experimenting with innovations in different innovation fields such as technical, organisational, financial, and commercialisation schemes. The aim of this third study is to provide insights into the challenges and difficulties faced by these actors in broadening the diffusion of the innovations they have been advancing. To perform this study, a methodological strategy is applied that combines a transdisciplinary mutual learning format with qualitative content analysis techniques. The fourth and last study is a conceptual disquisition. It develops a conceptual framework that (a) provides better accounts for the particularities of endeavours aimed at the diffusion of knowledge and practices from the bottom-up across local contexts and social scales, and (b) advances first conceptual steps towards an explicit account for the role that innovation research (and innovation researchers) can assume for the actual realisation of diffusion. The main findings or contributions of the doctoral research can be categorised into four subjects: 1) Bottom-up initiatives contribute to the diffusion of sustainable innovations by: (a) mobilising transformative resources for inducing diffusion in their scope of action; both their own as well as others’ resources; and (b) creating spaces for experimentation in which interventions can be tested (and if necessary adjusted) in order to ensure the proper deployment of innovations. 2) In their efforts to advance the diffusion of sustainability innovations, bottom-up initiatives contribute to social changes for (a) ensuring the effective deployment of the innovations, for instance: • by supporting change in the sociotechnical configurations that enable and constrain the daily practices of single households, in a way that permits the innovation’s proper operation; and • by reshaping local socioeconomic structures in order to ensure and sustain the supply of services and goods linked to the implemented innovation; (b) building local available storage of transformative resources, that is, the consolidation of local organisational structures that facilitate the building and binding of knowledge, financial capital, people’s skills, access to networks among other resources. Moreover, knowledge and practices from the bottom-up can transit to other social scales, and in this way contribute to social changes beyond their localities. 3) A conceptualisation of innovation diffusion, in which the work of academic researchers studying innovation is a constitutive part of transdisciplinary knowledge articulations that promote diffusion. In this way transdisciplinary research alliances can be envisioned in which researchers investigate about, with, and for bottom-up initiatives. 4) Contributions to the consolidation, systematisation, and dissemination of strategies that are applied by farmers associations in order to strength the economic, social, environmental, and cultural dimensions of Colombian family farmers. The contours of two research horizons for further research are outlined, they can be briefly described as: (a) explorations of diffusion beyond bottom-up localities involving changes of socio-political structures and (b) the development of conceptual and methodological frameworks for the realisation of bottom-up transformative research alliances.