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Die sog. Blockchain-Technologie ist gegenwärtig kaum mehr aus der Medienberichterstattung wegzudenken; es kann sogar von einem regelrechten Hype gesprochen werden, der an die Ursprungszeiten des Internet erinnert. Dabei handelt es sich keineswegs um ein neues Phänomen: Die Vorläufer der heutigen Blockchain entstanden schon in den 90er Jahren. Die heute bekannte Ausgestaltung findet ihren Ursprung in der Bitcoin-Blockchain, die fast ausschliesslich als Plattform für die Schaffung von und den Handel mit Kryptowährungen eingesetzt wurde. Zwischenzeitlich sind zahlreiche weitere Anwendungsfelder erschlossen worden und die Technologie erfährt eine stete Weiterentwicklung. Mit Hilfe einer Blockchain können Vermögenswerte geschaffen und verschoben, Handel betrieben und Unternehmens-finanzierungen getätigt werden. Die rege Nutzung der Technologie wirft zahlreiche Fragen auf, welche auch das Recht beschlagen. Die vorliegende Arbeit befasst sich mit einer privatrechtlichen Sicht auf die Blockchain-Technologie. Ihr Kern ist eine Auslegordnung derselben, mit einem besonderen Fokus auf Smart Contracts und deren Einordnung in das allgemeine Vertragsrecht. Auf weitere (zentrale) diskussionswürdige Punkte wie bspw. prozessuale Fragen, den Datenschutz oder konkursrechtliche Probleme wird vorliegend nicht eingegangen. Auch nicht behandelt wird die Einbettung von Dateneigentum in unsere Rechtsordnung.
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Malleable technologies promise almost infinite applications for organizations. Users can utilize the generic functionalities of such technologies to support personal tasks or combine and adapt them to create custom artefacts and, hence, shape organizational routines. Although users have a crucial part in the transition from generic potentials to effective use of malleable technologies, we know little about processes and factors that facilitate users in this endeavor and how created artefacts evolve over time. This dissertation presents three studies, which target these research gaps. The studies draw on affordance theory, cognitive load theory, routine theory and momentum of change and apply qualitative and quantitative methods to the case of a malleable technology implementation project in an organization. The results suggest that users perceive and actualize afforded potentials of malleable technologies through different processes, which depend on user characteristics and local environmental factors. Moreover, the longitudinal observations show that users often perform a series of changes, when they form custom artefacts from malleable technologies. The intensity of these changes can be described as momentum that depends on factors like the existing artefact or the embeddedness of the related routine. Overall, the dissertation findings open the black box of user-driven change under malleable technology and help to explain variations in the created momentum of change.
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Anthropogenic climate change is the most demanding challenge humanity has to face in the ongoing 21st century and beyond. This dissertation delves deeper into enhancing the knowledge on the major drivers of climate change and its mitigation. Thus, all four articles focus on the macro-level analysis of countries over time, applying causal inference. Specifically, the dissertation addresses the predictors of national carbon dioxide (CO2) emissions (article 1), the controversial debate on carbon leakage from developed to developing countries (article 2), the influence of social inequality on CO2 emissions (article 3), and the role of forests as climate solution as well as the drivers of forest loss and its gain (article 4). Altogether, the results suggest that population growth is a major driver of CO2 emissions and deforestation. Another key factor is increasing wealth. However, the effect of economic growth is double-edged: On the one hand, rising gross domestic product (GDP) almost proportionally boosts carbon emissions so far. On the other hand, growth in GDP contributes to enhance forest cover. Minor carbon-abating effects are observed for energy prices, technological progress, and international environmental agreements. Designating and managing protected areas drives forest gain. Furthermore, social inequality and international trade are not substantially related to CO2 emissions. Particularly, there is no evidence for carbon leakage from developed to developing countries. Given the challenge of emissions abatement, natural climate solutions are promising for near-term and large­scale sequestration of carbon. As the fourth article highlights, dangerous climate change could be prevented by doubling current forest cover.
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Die nach Richard Wagner annotierten Orchesterstimmen der Jupiter-Sinfonie (KV 551) von Wolfgang Amadé Mozart der Allgemeinen Musikgesellschaft Zürich bilden die Grundlage dieser Arbeit. Sie geben Aufschluss über Wagners Interpretationsansatz. Neben der Entwicklung des Dirigierens bis zu Wagner, wird auch die Rezeptionsgeschichte von Mozarts Jupiter-Sinfonie nachzuzeichnen versucht. Weiter werden die Interpretationen der Sinfonie von nachkommenden Dirigenten anhand von annotierten Partituren, Aufnahmen sowie philologischen Quellen untersucht und in Zusammenhang mit der Ästhetik Wagners gebracht. Die Frage nach der Existenz einer Wagner-Traditions-Linie anhand der Jupiter-Sinfonie, wird aus verschiedenen Blickwinkeln behandelt.
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Terahertz (THz) radiation denotes the portion of the electromagnetic spectrum lying between the infrared and microwave bands, corresponding to frequencies in the range 0.1-10 THz. The most intriguing feature of using THz waves is their ability to penetrate several non-conducting and optically opaque materials, such as plastics, textiles, paper, and some building materials as well as intrinsic semiconductors. While this property is also shared by microwaves, THz radiation provides a better spatial resolution thanks to the shorter wavelength, thereby imaging hidden objects with sub-millimeter resolution. The non-ionizing nature of THz radiation when it interacts with living tissues also makes THz imaging techniques promising for biomedical and biological applications. In this thesis, I focus on the development and implementation of THz imaging techniques. All the techniques presented here belong to the realm of coherent lensless imaging, aiming at reconstructing the amplitude and phase of the wavefront diffracted by an unknown object, illuminated with coherent radiation, based on measurements of the intensity of their diffraction pattern recorded with a camera. The fact that the imaging process is carried out fully computationally and without the need of lenses has a crucial impact on the experimental setup, which is therefore compact and can be better tailored to real-life applications. In particular, I am going to discuss both theoretical and experimental aspects of synthetic aperture THz off-axis digital holography, the first experimental demonstration of THz ptychography and how to image objects hidden behind weakly and strongly diffracting barriers. A potential biomedical application for such THz imaging techniques will also be suggested.
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Cold high-Alpine glaciers are invaluable archives of past climate and atmospheric composition. Especially trace element records from high-Alpine ice cores and snow pits contain comprehensive information about paleo atmospheric changes. Monitoring past environmental pollution is particularly important for Europe, one of the world’s most densely populated and most highly industrialized regions. Trace element records from different high-Alpine sites revealed that human activities have significantly impacted the composition of the atmosphere during the last 150 years. Unanswered questions still remain. For instance, the onset of European anthropogenic impact on the atmosphere, such as the impact from the earliest metal production in Western Europe interfering with natural background levels of trace elements from mineral dust deposition, has not been identified yet. Due to the current global climate warming, particularly pronounced for mountain regions such as the European Alps, many glaciers even at high altitudes are increasingly in danger to significantly suffer from melting. Apart from severe socioeconomic impacts caused by glacial melting, as Alpine glaciers are the major fresh water resource in Europe, meltwater percolation has been shown to substantially alter the information stored in these environmental archives. To further use trace element records as paleo atmospheric archives to investigate the open research questions, the influence of melting on the preservation of trace elements in snow and ice needs to be thoroughly understood. Only little and ambiguous information is available on meltwater-induced relocation of trace elements so far. The behavior of atmospheric impurities during meltwater percolation is assumed to be strongly dependent on their location in the ice microstructure. This spatial distribution of impurities at a grain scale is likely to be determined by rearrangement processes during snow metamorphism. However, information on the micro scale distribution of trace elements in Alpine snow and glacier ice and on the corresponding role of snow metamorphism is not yet available. In this thesis, part of the interdisciplinary “Microscale Distribution of Impurities in Snow and Glacier Ice (MiSo)” project, the behavior of trace elements during melting of high-Alpine snow and glacier ice was extensively investigated to assess their potential as reconstruction proxies in melt-affected ice core and snow pit records. Particular attention was dedicated to understand the underlying causes and mechanisms leading to the observed trace element behavior during melting, including the spatial distribution of trace elements in high-Alpine glacier ice and rearrangement processes during snow metamorphism. To examine the impact of melting on the preservation of trace elements of natural and anthropogenic origin, a 50 m segment of an ice core from upper Grenzgletscher, Switzerland, was analyzed for 35 trace elements using discrete inductively coupled plasma mass spectrometry. This segment included a 16 m section affected by meltwater percolation in the firn part. A fractionation depending on water solubility and location at the grain scale was observed. Ba, Ca, Cd, Co, Mg, Mn, Na, Ni, Sr, and Zn revealed significant concentration depletion, while Ag, Al, Bi, Cu, Cs, Fe, Li, Mo, Pb, Rb, Sb, Th, Tl, U, V, W, Zr, and the rare-earth elements (Ce, Eu, La, Nd, Pr, Sc, Sm, Yb) were well preserved. Trace elements likely to originate from insoluble minerals were found to be mostly preserved, even though typically enriched on grain surfaces. Immobility with meltwater percolation is a result of their insolubility in water. Trace elements linked to water-soluble particles revealed a variable meltwater-mobility. While trace elements occurring in ultra-low concentrations tend to be preserved due to incorporation into the ice lattice, abundant trace elements are prone to meltwater-induced relocation due to exceeded solubility limits in ice and consequent segregation to grain surfaces. The size of the corresponding ions was found to have a negligible effect. For ice cores from high-Alpine sites partially affected by melting, records of Ag, Al, Bi, Cu, Cs, Fe, Li, Mo, Pb, Rb, Sb, Th, Tl, U, V, W, Zr, and the rare-earth elements are proposed to be still applicable as robust environmental proxies. In collaboration with the Swiss Snow and Avalanche Research Institute, the impact of melting on the preservation of trace elements in snow was studied by conducting an extensive snow pit campaign at the Weissfluhjoch test site, Switzerland, with regular sampling from January to June 2017, to monitor the behavior of trace elements during melting of the snow pack. Comparison of snow pit profiles representing dry (insignificant occurrence of melting) and wet conditions (snow pack heavily soaked with meltwater) revealed a preferential loss of certain trace elements depending on their presumed microscopic location and their water solubility. The obtained elution behavior matched the findings from the upper Grenzgletscher ice core. Variable mobility was observed for trace elements originating from water-soluble particles, where low abundant trace elements were preferably retained. Concentration-independent preservation was visible for water-insoluble trace elements, owing to their meltwater immobility. Precipitation at the two 180 km distant high-Alpine sites upper Grenzgletscher andWeissfluhjoch is characteristic for Central European atmospheric aerosol composition. As the large majority of investigated trace elements revealed a consistent behavior with meltwater percolation at those two sites, the proposed applicability of trace elements as reconstruction proxies in melt-affected ice core and snow pit records is therefore most likely representative for the entire Alpine region. The redistribution of six major ions (ammonium, calcium, chloride, fluoride, sodium, sulfate) and 35 trace elements during artificial and natural snow metamorphism was extensively investigated in another collaboration with the Swiss Snow and Avalanche Research Institute. For this, artificial and natural snow samples were exposed to a controlled temperature gradient of 40 K m−1 in the laboratory for up to 90 days. Simultaneously, the distribution of the same atmospheric impurities was studied in samples taken from different depths of the snow pack at the Weissfluhjoch test site, each corresponding to a distinct exposure time of a natural temperature gradient. Initial snow structures, monitored by X-ray micro-tomography, and impurity distribution, determined by elution experiments, varied strongly between the different snow samples. However, with progressing snow metamorphism, snow structures became similar and ions exhibiting a high solubility in ice (ammonium, fluoride, chloride) were gradually buried in the ice interiors, whereas calcium, sodium, and sulfate were enriched at ice crystal surfaces. The redistribution of atmospheric impurities during snow metamorphism was shown to be strongly dependent on the temperature gradient, the exposure time, and the chemical composition. The observed preferred incorporation of certain species into the ice interior during snow metamorphism is correlated with their persistence during meltwater percolation. The elution experiments allowed investigation of water-soluble major ions only, whereas results for the trace elements could not be interpreted due to non-quantitative dissolubility of trace elements in the deployed eluent (ultra-pure water). An analytical method for the direct in situ analysis of trace elements at a submillimeter resolution in high-Alpine glacier ice was developed in collaboration with the Institute of Geochemistry and Petrology at ETH Zurich. This method is based on laser ablation inductively coupled plasma mass spectrometry. The development process comprised the construction and the consistent further development of a cooled sample holder, featuring an automatic coolant leakage detection system and compatibility to a commercially available laser ablation system, as well as choice of the optimal cooling medium, customization of the pre-existing laser ablation hardware and software, and the development of additional equipment for both sample preparation and handling. In addition to this, a measurement procedure for high-Alpine glacier ice was established, involving the determination of appropriate laser ablation parameters and setting up a procedure for signal intensity quantification. The availability of an internal standard in ice was evaluated and an approach to prepare matrix-matched ice standards from multi-element standard solutions for external calibration was established. The acidity of the multi-element solutions and the storage time of the ice standard after preparation were found to have the most significant impact on the calibration. Preliminary measurements of high-Alpine glacier ice samples from upper Grenzgletscher demonstrated that samples exhibiting an overwhelming mineral dust abundance do not provide evidence for a linkage between micro-scale distribution of trace elements and the grain boundary network. Such a dispersion of atmospheric contaminants in the ice matrix has also very recently been reported for layers with high impurity enrichment in deep ice from Antarctica and Greenland. Future work should involve in situ analysis of high-Alpine glacier ice exhibiting ultra-low levels of trace elements to minimize the influence of dust particles on the fractionation of trace elements at a grain scale and to further directly corroborate the indirect assessment of trace element location in the firn part of the ice core from upper Grenzgletscher. This requires further background suppression of the developed micro analytical method. The proposed applicability of trace elements as reconstruction proxies in melt-affected high-Alpine ice core and snow pit records should be reviewed for other regions with a different overall trace element composition, as high-mountain glaciers worldwide are increasingly affected by melting. For instance, the presence of water-insoluble trace elements, less prone to meltwater-induced relocation, is favored in glacier ice where higher mineral dust content prevails. Additionally, the impact of melting on the preservation of other reconstruction proxies, such as mercury or black carbon, should be investigated to possibly expand the set of rather “meltwater-persistent” proxies.
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In today's difficult global economy, work related stress is high. Stress — along with other health impairing factors — can affect work productivity, satisfaction, safety, absenteeism, turnover, and even workplace violence, which is why organizations are increasingly turning to occupational health psychology to develop, maintain, and promote the health of employees. In occupational health psychology, one of the core assumptions is that conditions at work affect employee well-being. Appreciation is one of the positive aspects of work, which can promote optimal human functioning and well-being. The current Swiss National Foundation project is embedded in this context. The four main goals of the project whereas follow: 1) Longitudinally test, if appreciation predicts well-being; 2) investigate if some sources of appreciation are more important than others; 3) to test if appreciation interacts with stressors, such that the effects of stressors are attenuated if appreciation is high; and 4) investigate the short-term effects of appreciation on well-being through diary methods and analyze the interaction with positive and negative daily experiences. The first and third paper written in the course of this project present longitudinal data and confirm the positive effects of appreciation over time (first objective). Furthermore, we tried to disentangle within-person and between-person effects, confirming previous findings that an effect happening at one level, cannot automatically be assumed to happen at another. The second objective of this dissertational project was to investigate if different sources of appreciation are more important than others. Our results clearly showed, that supervisors, followed by work colleagues, where the most important sources of appreciation (papers I-III). The third aim of the project was to test if appreciation interacts with stressors, such that the effects of stressors are attenuated if appreciation is high. In our first and second paper we find partial confirmation for this hypothesis. Appreciation did buffer the negative effect of illegitimate tasks on affective well-being, but only on a within-person level (paper I). On a daily level, appreciation did also work as a buffer for negative daily experiences (paper II). The fourth aim of the study was to investigate appreciation and the short-term consequences on well-being on an inter-individual level. We also wanted to find out, if there was an interplay with positive and negative daily experiences at work. In our second article we present data from our diary study, where we captured the short-term fluctuations in appreciation, indicators of well-being as well as how many positive and negative experiences participants made daily. Again, appreciation from supervisors had the strongest effect on well-being. Also, appreciation from colleagues had a significant effect on well-being after work, but only when participants were confronted with negative experiences that day. Furthermore, we found that appreciation from supervisors buffered the negative impact of daily negative events. Appreciation from colleagues did not.
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