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Lamprophyre sind porphyrische, aus Mantelschmelzen gebildete Gesteine, die meist in Form von Gängen auftreten. Sie zeichnen sich durch auffällige und charakteristische texturelle, chemische und mineralogische Eigenschaften aus. Als ehemalige Mantelschmelzen liefern sie Information sowohl über Bedingungen der Schmelzbildung im Mantel als auch über geodynamische Prozesse, die zu metasomatischer Veränderung des Mantels geführt haben. Im Saxothuringikum Mitteleuropas, am Nordrand des Böhmischen Massivs, gibt es zahlreiche Lamprophyrvorkommen, die hier zur Charakterisierung der Mantelentwicklung während der variszischen Orogenese dienen. Die vorliegende Arbeit befaßt sich mit den mineralogischen, geochemischen und isotopischen (Sr-Nd-Pb) Signaturen von spätvariszischen kalkalkalischen Lamprophyren, von postvariszischen ultramafischen Lamprophyren, von Alkalibasalten der Lausitz und, zum Vergleich, von prävariszischen Gabbros. Darüberhinaus nutzt die Arbeit Lithium-Isotopensignaturen kombiniert mit Sr-Nd-Pb–Isotopendaten spätvariszischer kalkalkalischer Lamprophyre aus drei variszischen Domänen (Erzgebirge, Lausitz, Sudeten) zur Erkundung der lokalen Mantelüberprägungen während der variszischen Orogenese.
Metabolically active microbial communities are present in a wide range of subsurface environments. Techniques like enumeration of microbial cells, activity measurements with radiotracer assays and the analysis of porewater constituents are currently being used to explore the subsurface biosphere, alongside with molecular biological analyses. However, many of these techniques reach their detection limits due to low microbial activity and abundance. Direct measurements of microbial turnover not just face issues of insufficient sensitivity, they only provide information about a single specific process but in sediments many different process can occur simultaneously. Therefore, the development of a new technique to measure total microbial activity would be a major improvement. A new tritium-based hydrogenase-enzyme assay appeared to be a promising tool to quantify total living biomass, even in low activity subsurface environments. In this PhD project total microbial biomass and microbial activity was quantified in different subsurface sediments using established techniques (cell enumeration and pore water geochemistry) as well as a new tritium-based hydrogenase enzyme assay. By using a large database of our own cell enumeration data from equatorial Pacific and north Pacific sediments and published data it was shown that the global geographic distribution of subseafloor sedimentary microbes varies between sites by 5 to 6 orders of magnitude and correlates with the sedimentation rate and distance from land. Based on these correlations, global subseafloor biomass was estimated to be 4.1 petagram-C and ~0.6 % of Earth's total living biomass, which is significantly lower than previous estimates. Despite the massive reduction in biomass the subseafloor biosphere is still an important player in global biogeochemical cycles. To understand the relationship between microbial activity, abundance and organic matter flux into the sediment an expedition to the equatorial Pacific upwelling area and the north Pacific Gyre was carried out. Oxygen respiration rates in subseafloor sediments from the north Pacific Gyre, which are deposited at sedimentation rates of 1 mm per 1000 years, showed that microbial communities could survive for millions of years without fresh supply of organic carbon. Contrary to the north Pacific Gyre oxygen was completely depleted within the upper few millimeters to centimeters in sediments of the equatorial upwelling region due to a higher supply of organic matter and higher metabolic activity. So occurrence and variability of electron acceptors over depth and sites make the subsurface a complex environment for the quantification of total microbial activity. Recent studies showed that electron acceptor processes, which were previously thought to thermodynamically exclude each other can occur simultaneously. So in many cases a simple measure of the total microbial activity would be a better and more robust solution than assays for several specific processes, for example sulfate reduction rates or methanogenesis. Enzyme or molecular assays provide a more general approach as they target key metabolic compounds. Since hydrogenase enzymes are ubiquitous in microbes, the recently developed tritium-based hydrogenase radiotracer assay is applied to quantify hydrogenase enzyme activity as a parameter of total living cell activity. Hydrogenase enzyme activity was measured in sediments from different locations (Lake Van, Barents Sea, Equatorial Pacific and Gulf of Mexico). In sediment samples that contained nitrate, we found the lowest cell specific enzyme activity around 10^(-5) nmol H_(2) cell^(-1) d^(-1). With decreasing energy yield of the electron acceptor used, cell-specific hydrogenase activity increased and maximum values of up to 1 nmol H_(2) cell^(-1) d^(-1) were found in samples with methane concentrations of >10 ppm. Although hydrogenase activity cannot be converted directly into a turnover rate of a specific process, cell-specific activity factors can be used to identify specific metabolism and to quantify the metabolically active microbial population. In another study on sediments from the Nankai Trough microbial abundance and hydrogenase activity data show that both the habitat and the activity of subseafloor sedimentary microbial communities have been impacted by seismic activities. An increase in hydrogenase activity near the fault zone revealed that the microbial community was supplied with hydrogen as an energy source and that the microbes were specialized to hydrogen metabolism.
The study of outcrop modeling is located at the interface between two fields of expertise, Sedimentology and Computing Geoscience, which respectively investigates and simulates geological heterogeneity observed in the sedimentary record. During the last past years, modeling tools and techniques were constantly improved. In parallel, the study of Phanerozoic carbonate deposits emphasized the common occurrence of a random facies distribution along single depositional domain. Although both fields of expertise are intrinsically linked during outcrop simulation, their respective advances have not been combined in literature to enhance carbonate modeling studies. The present study re-examines the modeling strategy adapted to the simulation of shallow-water carbonate systems, based on a close relationship between field sedimentology and modeling capabilities. In the present study, the evaluation of three commonly used algorithms Truncated Gaussian Simulation (TGSim), Sequential Indicator Simulation (SISim), and Indicator Kriging (IK), were performed for the first time using visual and quantitative comparisons on an ideally suited carbonate outcrop. The results show that the heterogeneity of carbonate rocks cannot be fully simulated using one single algorithm. The operating mode of each algorithm involves capabilities as well as drawbacks that are not capable to match all field observations carried out across the modeling area. Two end members in the spectrum of carbonate depositional settings, a low-angle Jurassic ramp (High Atlas, Morocco) and a Triassic isolated platform (Dolomites, Italy), were investigated to obtain a complete overview of the geological heterogeneity in shallow-water carbonate systems. Field sedimentology and statistical analysis performed on the type, morphology, distribution, and association of carbonate bodies and combined with palaeodepositional reconstructions, emphasize similar results. At the basin scale (x 1 km), facies association, composed of facies recording similar depositional conditions, displays linear and ordered transitions between depositional domains. Contrarily, at the bedding scale (x 0.1 km), individual lithofacies type shows a mosaic-like distribution consisting of an arrangement of spatially independent lithofacies bodies along the depositional profile. The increase of spatial disorder from the basin to bedding scale results from the influence of autocyclic factors on the transport and deposition of carbonate sediments. Scale-dependent types of carbonate heterogeneity are linked with the evaluation of algorithms in order to establish a modeling strategy that considers both the sedimentary characteristics of the outcrop and the modeling capabilities. A surface-based modeling approach was used to model depositional sequences. Facies associations were populated using TGSim to preserve ordered trends between depositional domains. At the lithofacies scale, a fully stochastic approach with SISim was applied to simulate a mosaic-like lithofacies distribution. This new workflow is designed to improve the simulation of carbonate rocks, based on the modeling of each scale of heterogeneity individually. Contrarily to simulation methods applied in literature, the present study considers that the use of one single simulation technique is unlikely to correctly model the natural patterns and variability of carbonate rocks. The implementation of different techniques customized for each level of the stratigraphic hierarchy provides the essential computing flexibility to model carbonate systems. Closer feedback between advances carried out in the field of Sedimentology and Computing Geoscience should be promoted during future outcrop simulations for the enhancement of 3-D geological models.
Several mechanisms are proposed to be part of the earthquake triggering process, including static stress interactions and dynamic stress transfer. Significant differences of these mechanisms are particularly expected in the spatial distribution of aftershocks. However, testing the different hypotheses is challenging because it requires the consideration of the large uncertainties involved in stress calculations as well as the appropriate consideration of secondary aftershock triggering which is related to stress changes induced by smaller pre- and aftershocks. In order to evaluate the forecast capability of different mechanisms, I take the effect of smaller--magnitude earthquakes into account by using the epidemic type aftershock sequence (ETAS) model where the spatial probability distribution of direct aftershocks, if available, is correlated to alternative source information and mechanisms. Surface shaking, rupture geometry, and slip distributions are tested. As an approximation of the shaking level, ShakeMaps are used which are available in near real-time after a mainshock and thus could be used for first-order forecasts of the spatial aftershock distribution. Alternatively, the use of empirical decay laws related to minimum fault distance is tested and Coulomb stress change calculations based on published and random slip models. For comparison, the likelihood values of the different model combinations are analyzed in the case of several well-known aftershock sequences (1992 Landers, 1999 Hector Mine, 2004 Parkfield). The tests show that the fault geometry is the most valuable information for improving aftershock forecasts. Furthermore, they reveal that static stress maps can additionally improve the forecasts of off--fault aftershock locations, while the integration of ground shaking data could not upgrade the results significantly. In the second part of this work, I focused on a procedure to test the information content of inverted slip models. This allows to quantify the information gain if this kind of data is included in aftershock forecasts. For this purpose, the ETAS model based on static stress changes, which is introduced in part one, is applied. The forecast ability of the models is systematically tested for several earthquake sequences and compared to models using random slip distributions. The influence of subfault resolution and segment strike and dip is tested. Some of the tested slip models perform very good, in that cases almost no random slip models are found to perform better. Contrastingly, for some of the published slip models, almost all random slip models perform better than the published slip model. Choosing a different subfault resolution hardly influences the result, as long the general slip pattern is still reproducible. Whereas different strike and dip values strongly influence the results depending on the standard deviation chosen, which is applied in the process of randomly selecting the strike and dip values.
Die vorliegende Arbeit untersucht das sozio-kulturelle und institutionelle Umfeld der Organisationen des öffentlichen Sektors in der Mongolei, das signifikante Einflüsse auf die aktuellen Reformbemühungen in der öffentlichen Verwaltung hat. Die Studie stützt sich auf die Kultur- und Werttheorie. Die regelkonforme Verhaltensweise, Gemeinschaftsfavorisierende strenge Hierarchie, die fatalistische Annahme einer Autorität als unvermeidlich und unkontrollierbar sowie ein auf möglichst eigenständige Entscheidung und Meinungsbildung angestrebter Individualismus sind die weitverbreiteten kulturellen Verhaltensformen bei den Organisationen des öffentlichen Sektors der Mongolei. Dementsprechend streben die Beschäftigten des öffentlichen Dienstes uneigennützig das Wohlergehen der Bevölkerung, die Einhaltung der öffentlichen Regeln, die einvernehmlichen Beziehungen der Menschen zueinander sowie die Sicherheit und Nachhaltigkeit des Lebens an. Bestimmte Wertvorstellungen zur Selbstbestimmung, wie persönliche Geisteshaltung, eigenständiges Handeln sowie Kreativität sind für sie sehr wichtig. Dieser sozio- kulturelle Kontext hat große Auswirkungen auf das Arbeitsverhalten und auf die Aktivitäten der Beschäftigten des öffentlichen Dienstes zur Umsetzung von Reformen in der öffentlichen Verwaltung. Daher ist eine institutionelle Führung als Förderer und Beschützer von Wertesystemen bei der Umsetzung von Reformen in den hiesigen Institutionen unerlässlich.
Antarctic glacier forfields are extreme environments and pioneer sites for ecological succession. The Antarctic continent shows microbial community development as a natural laboratory because of its special environment, geographic isolation and little anthropogenic influence. Increasing temperatures due to global warming lead to enhanced deglaciation processes in cold-affected habitats and new terrain is becoming exposed to soil formation and accessible for microbial colonisation. This study aims to understand the structure and development of glacier forefield bacterial communities, especially how soil parameters impact the microorganisms and how those are adapted to the extreme conditions of the habitat. To this effect, a combination of cultivation experiments, molecular, geophysical and geochemical analysis was applied to examine two glacier forfields of the Larsemann Hills, East Antarctica. Culture-independent molecular tools such as terminal restriction length polymorphism (T-RFLP), clone libraries and quantitative real-time PCR (qPCR) were used to determine bacterial diversity and distribution. Cultivation of yet unknown species was carried out to get insights in the physiology and adaptation of the microorganisms. Adaptation strategies of the microorganisms were studied by determining changes of the cell membrane phospholipid fatty acid (PLFA) inventory of an isolated bacterium in response to temperature and pH fluctuations and by measuring enzyme activity at low temperature in environmental soil samples. The two studied glacier forefields are extreme habitats characterised by low temperatures, low water availability and small oligotrophic nutrient pools and represent sites of different bacterial succession in relation to soil parameters. The investigated sites showed microbial succession at an early step of soil formation near the ice tongue in comparison to closely located but rather older and more developed soil from the forefield. At the early step the succession is influenced by a deglaciation-dependent areal shift of soil parameters followed by a variable and prevalently depth-related distribution of the soil parameters that is driven by the extreme Antarctic conditions. The dominant taxa in the glacier forefields are Actinobacteria, Acidobacteria, Proteobacteria, Bacteroidetes, Cyanobacteria and Chloroflexi. The connection of soil characteristics with bacterial community structure showed that soil parameter and soil formation along the glacier forefield influence the distribution of certain phyla. In the early step of succession the relative undifferentiated bacterial diversity reflects the undifferentiated soil development and has a high potential to shift according to past and present environmental conditions. With progressing development environmental constraints such as water or carbon limitation have a greater influence. Adapting the culturing conditions to the cold and oligotrophic environment, the number of culturable heterotrophic bacteria reached up to 108 colony forming units per gram soil and 148 isolates were obtained. Two new psychrotolerant bacteria, Herbaspirillum psychrotolerans PB1T and Chryseobacterium frigidisoli PB4T, were characterised in detail and described as novel species in the family of Oxalobacteraceae and Flavobacteriaceae, respectively. The isolates are able to grow at low temperatures tolerating temperature fluctuations and they are not specialised to a certain substrate, therefore they are well-adapted to the cold and oligotrophic environment. The adaptation strategies of the microorganisms were analysed in environmental samples and cultures focussing on extracellular enzyme activity at low temperature and PLFA analyses. Extracellular phosphatases (pH 11 and pH 6.5), β-glucosidase, invertase and urease activity were detected in the glacier forefield soils at low temperature (14°C) catalysing the conversion of various compounds providing necessary substrates and may further play a role in the soil formation and total carbon turnover of the habitat. The PLFA analysis of the newly isolated species C. frigidisoli showed that the cold-adapted strain develops different strategies to maintain the cell membrane function under changing environmental conditions by altering the PLFA inventory at different temperatures and pH values. A newly discovered fatty acid, which was not found in any other microorganism so far, significantly increased at decreasing temperature and low pH and thus plays an important role in the adaption of C. frigidisoli. This work gives insights into the diversity, distribution and adaptation mechanisms of microbial communities in oligotrophic cold-affected soils and shows that Antarctic glacier forefields are suitable model systems to study bacterial colonisation in connection to soil formation.
Data integration aims to combine data of different sources and to provide users with a unified view on these data. This task is as challenging as valuable. In this thesis we propose algorithms for dependency discovery to provide necessary information for data integration. We focus on inclusion dependencies (INDs) in general and a special form named conditional inclusion dependencies (CINDs): (i) INDs enable the discovery of structure in a given schema. (ii) INDs and CINDs support the discovery of cross-references or links between schemas. An IND “A in B” simply states that all values of attribute A are included in the set of values of attribute B. We propose an algorithm that discovers all inclusion dependencies in a relational data source. The challenge of this task is the complexity of testing all attribute pairs and further of comparing all of each attribute pair's values. The complexity of existing approaches depends on the number of attribute pairs, while ours depends only on the number of attributes. Thus, our algorithm enables to profile entirely unknown data sources with large schemas by discovering all INDs. Further, we provide an approach to extract foreign keys from the identified INDs. We extend our IND discovery algorithm to also find three special types of INDs: (i) Composite INDs, such as “AB in CD”, (ii) approximate INDs that allow a certain amount of values of A to be not included in B, and (iii) prefix and suffix INDs that represent special cross-references between schemas. Conditional inclusion dependencies are inclusion dependencies with a limited scope defined by conditions over several attributes. Only the matching part of the instance must adhere the dependency. We generalize the definition of CINDs distinguishing covering and completeness conditions and define quality measures for conditions. We propose efficient algorithms that identify covering and completeness conditions conforming to given quality thresholds. The challenge for this task is twofold: (i) Which (and how many) attributes should be used for the conditions? (ii) Which attribute values should be chosen for the conditions? Previous approaches rely on pre-selected condition attributes or can only discover conditions applying to quality thresholds of 100%. Our approaches were motivated by two application domains: data integration in the life sciences and link discovery for linked open data. We show the efficiency and the benefits of our approaches for use cases in these domains.
Black shales are sedimentary rocks with a high content of organic carbon, which leads to a dark grayish to black color. Due to their potential to contain oil or gas, black shales are of great interest for the support of the worldwide energy supply. An integrated seismic investigation of the Lower Palaeozoic black shales was carried out at the Danish island Bornholm to locate the shallow-lying Alum Shale layer and its surrounding formations and to characterize its potential as a source rock. Therefore, two seismic experiments at a total of three crossing profiles were carried out in October 2010 and in June 2012 in the southern part of the island. Two different active measurements were conducted with either a weight drop source or a minivibrator. Additionally, the ambient noise field was recorded at the study location over a time interval of about one day, and also a laboratory analysis of borehole samples was carried out. The seismic profiles were positioned as close as possible to two scientific boreholes which were used for comparative purposes. The seismic field data was analyzed with traveltime tomography, surface wave inversion and seismic interferometry to obtain the P-wave and S-wave velocity models of the subsurface. The P-wave velocity models which were determined for all three profiles clearly locate the Alum Shale layer between the Komstad Limestone layer on top and the Læså Sandstone Formation at the base of the models. The black shale layer has P-wave velocities around 3 km/s which are lower compared to the adjacent formations. Due to a very good agreement of the sonic log and the vertical velocity profiles of the two seismic lines, which are directly crossing the borehole where the sonic log was conducted, the reliability of the traveltime tomography is proven. A correlation of the seismic velocities with the content of organic carbon is an important task for the characterization of the reservoir properties of a black shale formation. It is not possible without calibration but in combination with a full 2D tomographic image of the subsurface it gives the subsurface distribution of the organic material. The S-wave model obtained with surface wave inversion of the vibroseis data of one of the profiles images the Alum Shale layer also very well with S-wave velocities around 2 km/s. Although individual 1D velocity models for each of the source positions were determined, the subsurface S-wave velocity distribution is very uniform with a good match between the single models. A really new approach described here is the application of seismic interferometry to a really small study area and a quite short time interval. Also new is the selective procedure of only using time windows with the best crosscorrelation signals to achieve the final interferograms. Due to the small scale of the interferometry even P-wave signals can be observed in the final crosscorrelations. In the laboratory measurements the seismic body waves were recorded for different pressure and temperature stages. Therefore, samples of different depths of the Alum Shale were available from one of the scientific boreholes at the study location. The measured velocities have a high variance with changing pressure or temperature. Recordings with wave propagation both parallel and perpendicular to the bedding of the samples reveal a great amount of anisotropy for the P-wave velocity, whereas the S-wave velocity is almost independent of the wave direction. The calculated velocity ratio is also highly anisotropic with very low values for the perpendicular samples and very high values for the parallel ones. Interestingly, the laboratory velocities of the perpendicular samples are comparable to the velocities of the field experiments indicating that the field measurements are sensitive to wave propagation in vertical direction. The velocity ratio is also calculated with the P-wave and S-wave velocity models of the field experiments. Again, the Alum Shale can be clearly separated from the adjacent formations because it shows overall very low vP/vS ratios around 1.4. The very low velocity ratio indicates the content of gas in the black shale formation. With the combination of all the different methods described here, a comprehensive interpretation of the seismic response of the black shale layer can be made and the hydrocarbon source rock potential can be estimated.
Internalin J (InlJ) gehört zu der Klasse der bakteriellen, cysteinhaltigen (leucine-rich repeat) LRR Proteine. Bei den Internalinen handelt es sich um meist invasions-assoziierte Proteine der Listerien. Die LRR-Domäne von InlJ ist aus 15 regelmäßig wiederkehrenden, stark konservierten Sequenzeinheiten (repeats, 21 Aminosäuren) aufgebaut. Ein interessantes Detail dieses Internalins ist das stark konservierte Cystein innerhalb der repeats. Daraus ergibt sich eine ungewöhnliche Anordnung von 12 Cysteinen in einem Stapel. Die Häufigkeit von Cysteinen in InlJ ist für ein extrazelluläres Protein von L. monocytogenes außergewöhnlich, und die Frage nach ihrer Funktion daher umso brennender. Im Vergleich zum ubiquitären Vorkommen der sogenannten repeat-Proteine in der Natur sind Studien zu ihrer Stabilität und Faltung nicht äquivalent vertreten. Die zentrale Eigenschaft der repeat-Proteine ist ihr modularer Aufbau, der durch einfache Topologie gekennzeichnet ist und auf kurzreichenden Wechselwirkungen basiert. Diese Topologie macht repeat-Proteine zu idealen Modellproteinen, um die stabilitätsrelevanten Wechselwirkungen zu separieren und zuzuordnen. In der vorliegenden Arbeit wurde die Faltung und Entfaltung von InlJ umfassend charakterisiert und die Relevanz der Cysteine näher beleuchtet. Die spektroskopische Charakterisierung von InlJ zeigte, dass dessen Faltungszustand durch zwei Tryptophane im N- und C-Terminus fluoreszenzspektroskopisch gut zugänglich ist. Die thermodynamische Stabilität wurde mittels fluoreszenz-detektierten, Guanidiniumchlorid-induzierten Gleichgewichtsexperimenten bestimmt. Um die kinetischen Eigenschaften von InlJ zu erfassen, wurden die Faltungs- sowie die Entfaltungsreaktion spektroskopisch untersucht. Die Identifizierung der produktiven Faltungsreaktion war lediglich durch die Anwendung des reversen Doppelsprungexperiments möglich. Die Auswertung erfolgte nach dem Zweizustandsmodell, wonach die Faltung dem „Alles-oder-Nichts“ Prinzip folgt. Die Gültigkeit dieser Annahme wurde durch die kinetische Charakterisierung bestätigt. Es wurde sowohl in den Gleichgewichtsexperimenten als auch in den kinetisch erhaltenen Daten eine hohe freie Stabilisierungsenthalpie festgestellt. Die hohe Stabilität von InlJ geht mit hoher Kooperativität einher. Die kinetischen Daten zeigen zudem, dass die hohe Kooperativität hauptsächlich der Faltungsreaktion entstammt. Der Tanford-Wert von 0.93 impliziert, dass die Oberflächenänderung während der Faltung bereits zum größten Teil erfolgt ist, bevor der Übergangszustand ausgebildet wurde. Direkte strukturelle Informationen über den Übergangszustand wurden mit Hilfe von Mutationsstudien erhalten. Zu diesem Zweck wurden 12 der 14 Cysteine gegen ein Alanin ausgetauscht. Die repeats 1 bis 11 von InlJ beinhalten jeweils ein Cystein, deren Anordnung eine Leiter ergibt. Deren Substitutionen haben einen vergleichbar destabilisierenden Effekt auf InlJ von durchschnittlich 4.8 kJ/mol. Die Verlangsamung der Faltung deutet daraufhin, dass die Interaktionen der repeats 5 bis 11 im Übergangszustand bereits voll ausgebildet sind. Demnach liegt bei InlJ ein zentraler Faltungsnukleus vor. Im Rahmen dieser Promotionsarbeit wurde eine hohe Stabilität und ein stark-kooperatives Verhalten für das extrazelluläre Protein InlJ beobachtet. Diese Erkenntnisse könnten wichtige Beiträge zur Entwicklung artifizieller repeat-Proteine leisten, deren Verwendung sich stetig ausweitet.
Climatic variations and human activity now and increasingly in the future cause land cover changes and introduce perturbations in the terrestrial carbon reservoirs in vegetation, soil and detritus. Optical remote sensing and in particular Imaging Spectroscopy has shown the potential to quantify land surface parameters over large areas, which is accomplished by taking advantage of the characteristic interactions of incident radiation and the physico-chemical properties of a material. The objective of this thesis is to quantify key soil parameters, including soil organic carbon, using field and Imaging Spectroscopy. Organic carbon, iron oxides and clay content are selected to be analyzed to provide indicators for ecosystem function in relation to land degradation, and additionally to facilitate a quantification of carbon inventories in semiarid soils. The semiarid Albany Thicket Biome in the Eastern Cape Province of South Africa is chosen as study site. It provides a regional example for a semiarid ecosystem that currently undergoes land changes due to unadapted management practices and furthermore has to face climate change induced land changes in the future. The thesis is divided in three methodical steps. Based on reflectance spectra measured in the field and chemically determined constituents of the upper topsoil, physically based models are developed to quantify soil organic carbon, iron oxides and clay content. Taking account of the benefits limitations of existing methods, the approach is based on the direct application of known diagnostic spectral features and their combination with multivariate statistical approaches. It benefits from the collinearity of several diagnostic features and a number of their properties to reduce signal disturbances by influences of other spectral features. In a following step, the acquired hyperspectral image data are prepared for an analysis of soil constituents. The data show a large spatial heterogeneity that is caused by the patchiness of the natural vegetation in the study area that is inherent to most semiarid landscapes. Spectral mixture analysis is performed and used to deconvolve non-homogenous pixels into their constituent components. For soil dominated pixels, the subpixel information is used to remove the spectral influence of vegetation and to approximate the pure spectral signature coming from the soil. This step is an integral part when working in natural non-agricultural areas where pure bare soil pixels are rare. It is identified as the largest benefit within the multi-stage methodology, providing the basis for a successful and unbiased prediction of soil constituents from hyperspectral imagery. With the proposed approach it is possible (1) to significantly increase the spatial extent of derived information of soil constituents to areas with about 40 % vegetation coverage and (2) to reduce the influence of materials such as vegetation on the quantification of soil constituents to a minimum. Subsequently, soil parameter quantities are predicted by the application of the feature-based soil prediction models to the maps of locally approximated soil signatures. Thematic maps showing the spatial distribution of the three considered soil parameters in October 2009 are produced for the Albany Thicket Biome of South Africa. The maps are evaluated for their potential to detect erosion affected areas as effects of land changes and to identify degradation hot spots in regard to support local restoration efforts. A regional validation, carried out using available ground truth sites, suggests remaining factors disturbing the correlation of spectral characteristics and chemical soil constituents. The approach is developed for semiarid areas in general and not adapted to specific conditions in the study area. All processing steps of the developed methodology are implemented in software modules, where crucial steps of the workflow are fully automated. The transferability of the methodology is shown for simulated data of the future EnMAP hyperspectral satellite. Soil parameters are successfully predicted from these data despite intense spectral mixing within the lower spatial resolution EnMAP pixels. This study shows an innovative approach to use Imaging Spectroscopy for mapping of key soil constituents, including soil organic carbon, for large areas in a non-agricultural ecosystem and under consideration of a partially vegetation coverage. It can contribute to a better assessment of soil constituents that describe ecosystem processes relevant to detect and monitor land changes. The maps further provide an assessment of the current carbon inventory in soils, valuable for carbon balances and carbon mitigation products.
Systems of Systems (SoS) have received a lot of attention recently. In this thesis we will focus on SoS that are built atop the techniques of Service-Oriented Architectures and thus combine the benefits and challenges of both paradigms. For this thesis we will understand SoS as ensembles of single autonomous systems that are integrated to a larger system, the SoS. The interesting fact about these systems is that the previously isolated systems are still maintained, improved and developed on their own. Structural dynamics is an issue in SoS, as at every point in time systems can join and leave the ensemble. This and the fact that the cooperation among the constituent systems is not necessarily observable means that we will consider these systems as open systems. Of course, the system has a clear boundary at each point in time, but this can only be identified by halting the complete SoS. However, halting a system of that size is practically impossible. Often SoS are combinations of software systems and physical systems. Hence a failure in the software system can have a serious physical impact what makes an SoS of this kind easily a safety-critical system. The contribution of this thesis is a modelling approach that extends OMG's SoaML and basically relies on collaborations and roles as an abstraction layer above the components. This will allow us to describe SoS at an architectural level. We will also give a formal semantics for our modelling approach which employs hybrid graph-transformation systems. The modelling approach is accompanied by a modular verification scheme that will be able to cope with the complexity constraints implied by the SoS' structural dynamics and size. Building such autonomous systems as SoS without evolution at the architectural level --- i. e. adding and removing of components and services --- is inadequate. Therefore our approach directly supports the modelling and verification of evolution.
Requirements engineers have to elicit, document, and validate how stakeholders act and interact to achieve their common goals in collaborative scenarios. Only after gathering all information concerning who interacts with whom to do what and why, can a software system be designed and realized which supports the stakeholders to do their work. To capture and structure requirements of different (groups of) stakeholders, scenario-based approaches have been widely used and investigated. Still, the elicitation and validation of requirements covering collaborative scenarios remains complicated, since the required information is highly intertwined, fragmented, and distributed over several stakeholders. Hence, it can only be elicited and validated collaboratively. In times of globally distributed companies, scheduling and conducting workshops with groups of stakeholders is usually not feasible due to budget and time constraints. Talking to individual stakeholders, on the other hand, is feasible but leads to fragmented and incomplete stakeholder scenarios. Going back and forth between different individual stakeholders to resolve this fragmentation and explore uncovered alternatives is an error-prone, time-consuming, and expensive task for the requirements engineers. While formal modeling methods can be employed to automatically check and ensure consistency of stakeholder scenarios, such methods introduce additional overhead since their formal notations have to be explained in each interaction between stakeholders and requirements engineers. Tangible prototypes as they are used in other disciplines such as design, on the other hand, allow designers to feasibly validate and iterate concepts and requirements with stakeholders. This thesis proposes a model-based approach for prototyping formal behavioral specifications of stakeholders who are involved in collaborative scenarios. By simulating and animating such specifications in a remote domain-specific visualization, stakeholders can experience and validate the scenarios captured so far, i.e., how other stakeholders act and react. This interactive scenario simulation is referred to as a model-based virtual prototype. Moreover, through observing how stakeholders interact with a virtual prototype of their collaborative scenarios, formal behavioral specifications can be automatically derived which complete the otherwise fragmented scenarios. This, in turn, enables requirements engineers to elicit and validate collaborative scenarios in individual stakeholder sessions – decoupled, since stakeholders can participate remotely and are not forced to be available for a joint session at the same time. This thesis discusses and evaluates the feasibility, understandability, and modifiability of model-based virtual prototypes. Similarly to how physical prototypes are perceived, the presented approach brings behavioral models closer to being tangible for stakeholders and, moreover, combines the advantages of joint stakeholder sessions and decoupled sessions.
Die Dissertation untersucht von Autorinnen (Louisa Johnson, Jane Loudon, Maria Theresa Earle, Gertrude Jekyll, Elizabeth von Arnim) verfasste Ratgeberliteratur zum Hausgarten für ein weibliches Lesepublikum, mit dem Anspruch an eine praktische Gartentätigkeit, im Zeitraum von 1839 bis 1900. Die Genderperspektive steht hieraus folgend im Mittelpunkt der vorliegenden Arbeit. Der Fokus auf die bürgerliche Mittelklasse ergibt sich aus der Autorinnenperspektive und der angesprochenen Leserschaft. Die Behandlung des Gartens wird einer Analyse unterzogen, die nach der weiblichen Sicht auf den Garten und einem spezifisch weiblichen Selbstverständnis der garteninteressierten bzw. gärtnernden Frauen fragt. In ihrer Beschäftigung mit dem Garten leisten die Frauen einen Beitrag zur Konzeption von männlich und weiblich, zur Bewertung von Geschlechternormen und deren Verhandlung. Das Schreiben und Lesen über den Garten sowie hieraus resultierende Handlungen waren mit der Konstruktion weiblicher Identität verknüpft. In ihrer befreienden Konzeption des Gartens heben sich diese Frauenstimmen zu Weiblichkeitsvorstellungen von anderen gesellschaftlichen zugeschriebenen Wirkungsbereichen ab. An die bürgerliche Frau herangetragene Rollenerwartungen werden in den Werken weder affirmativ bestätigt noch offen subversiv hinterfragt. Es handelt sich vielmehr um ein subtiles Unterlaufen durch das Anbieten von Handlungsfeldern, die dem Wunsch nach Selbstverwirklichung und Selbstbestimmung entgegen kamen. Im Garten als vermeintlich kleinem, hausnah-restriktivem Kontext nehmen die Frauen neue Rollen an und variieren diese. Der Beschäftigung mit dem Garten kommt daher ein protofeministischer Charakter vor dem Einsetzen der Ersten Frauenbewegung zu, so dass von einem Gartenfeminismus als Instrument zur weiblichen Bewusstwerdung gesprochen werden kann.
The Arctic is considered as a focal region in the ongoing climate change debate. The currently observed and predicted climate warming is particularly pronounced in the high northern latitudes. Rising temperatures in the Arctic cause progressive deepening and duration of permafrost thawing during the arctic summer, creating an ‘active layer’ with high bioavailability of nutrients and labile carbon for microbial consumption. The microbial mineralization of permafrost carbon creates large amounts of greenhouse gases, including carbon dioxide and methane, which can be released to the atmosphere, creating a positive feedback to global warming. However, to date, the microbial communities that drive the overall carbon cycle and specifically methane production in the Arctic are poorly constrained. To assess how these microbial communities will respond to the predicted climate changes, such as an increase in atmospheric and soil temperatures causing increased bioavailability of organic carbon, it is necessary to investigate the current status of this environment, but also how these microbial communities reacted to climate changes in the past. This PhD thesis investigated three records from two different study sites in the Russian Arctic, including permafrost, lake shore and lake deposits from Siberia and Chukotka. A combined stratigraphic approach of microbial and molecular organic geochemical techniques were used to identify and quantify characteristic microbial gene and lipid biomarkers. Based on this data it was possible to characterize and identify the climate response of microbial communities involved in past carbon cycling during the Middle Pleistocene and the Late Pleistocene to Holocene. It is shown that previous warmer periods were associated with an expansion of bacterial and archaeal communities throughout the Russian Arctic, similar to present day conditions. Different from this situation, past glacial and stadial periods experienced a substantial decrease in the abundance of Bacteria and Archaea. This trend can also be confirmed for the community of methanogenic archaea that were highly abundant and diverse during warm and particularly wet conditions. For the terrestrial permafrost, a direct effect of the temperature on the microbial communities is likely. In contrast, it is suggested that the temperature rise in scope of the glacial-interglacial climate variations led to an increase of the primary production in the Arctic lake setting, as can be seen in the corresponding biogenic silica distribution. The availability of this algae-derived carbon is suggested to be a driver for the observed pattern in the microbial abundance. This work demonstrates the effect of climate changes on the community composition of methanogenic archae. Methanosarcina-related species were abundant throughout the Russian Arctic and were able to adapt to changing environmental conditions. In contrast, members of Methanocellales and Methanomicrobiales were not able to adapt to past climate changes. This PhD thesis provides first evidence that past climatic warming led to an increased abundance of microbial communities in the Arctic, closely linked to the cycling of carbon and methane production. With the predicted climate warming, it may, therefore, be anticipated that extensive amounts of microbial communities will develop. Increasing temperatures in the Arctic will affect the temperature sensitive parts of the current microbiological communities, possibly leading to a suppression of cold adapted species and the prevalence of methanogenic archaea that tolerate or adapt to increasing temperatures. These changes in the composition of methanogenic archaea will likely increase the methane production potential of high latitude terrestrial regions, changing the Arctic from a carbon sink to a source.
Die nichtproteinogene Aminosäure GABA (γ-Aminobuttersäure) gilt als der wichtigste inhibitorische Neurotransmitter im Zentralnervensystem von Vertebraten sowie Invertebraten und vermittelt ihre Wirkung u. a. über die metabotropen GABAB-Rezeptoren. Bisher sind diese Rezeptoren bei Insekten nur rudimentär untersucht. Für die Amerikanische Großschabe als etablierter Modellorganismus konnte pharmakologisch eine modulatorische Rolle der GABAB-Rezeptoren bei der Bildung von Primärspeichel nachgewiesen werden. Ziel dieser Arbeit war eine umfassende Charakterisierung der GABAB-Rezeptor-Subtypen 1 und 2 von Periplaneta americana. Unter Verwendung verschiedenster Klonierungsstrategien sowie der Kooperationsmöglichkeit mit der Arbeitsgruppe von Prof. Dr. T. Miura (Hokkaido, Japan) in Hinsicht auf eine dort etablierte P. americana EST-Datenbank gelang die Klonierung von zwei Rezeptor-cDNAs. Die Analyse der abgeleiteten Aminosäuresequenzen auf GB-spezifische Domänen und konservierte Aminosäure-Reste, sowie der Vergleich zu bekannten GB Sequenzen anderer Arten legen nahe, dass es sich bei den isolierten Sequenzen um die GABAB-Rezeptor-Subtypen 1 und 2 (PeaGB1 und PeaGB2) handelt. Für die funktionelle und pharmakologische Charakterisierung des Heteromers aus PeaGB1 und PeaGB2 wurden Expressionskonstrukte für die Transfektion in HEK-flpTM-Zellen hergestellt. Das Heteromer aus PeaGB1 und PeaGB2 hemmt bei steigenden GABA-Konzentrationen die cAMP-Produktion. Die Substanzen SKF97541 und 3-APPA konnten als Agonisten identifiziert werden. CGP55845 und CGP54626 wirken als vollwertige Antagonisten. Das in vitro ermittelte pharmakologische Profil im Vergleich zur Pharmakologie an der isolierten Drüse bestätigt, dass die GABA-Wirkung in der Speicheldrüse tatsächlich von GBs vermittelt wird. Für die immunhistochemische Charakterisierung konnte ein spezifischer polyklonaler Antikörper gegen die extrazelluläre Schleife 2 des PeaGB1 generiert werden. Ein weiterer Antikörper, welcher gegen den PeaGB2 gerichtet ist, erwies sich hingegen nicht als ausreichend spezifisch. Western-Blot-Analysen bestätigen das Vorkommen beider Subtypen im Zentralnervensystem von P. americana. Zudem wird der PeaGB1 in der Speicheldrüse und in den Geschlechtsdrüsen der Schabenmännchen exprimiert. Immunhistochemische Analysen zeigen eine PeaGB1-ähnliche Markierung in den GABAergen Fasern der Speicheldrüse auf. Demnach fungiert der PeaGB1 hier als Autorezeptor. Weiterhin konnte eine PeaGB1-ähnliche Markierung in nahezu allen Gehirnneuropilen festgestellt werden. Auch die akzessorischen Drüsen der Männchen, Pilzdrüse und Phallusdrüse, sind PeaGB1-immunreaktiv.
The problem under consideration in the thesis is a two level atom in a photonic crystal and a pumping laser. The photonic crystal provides an environment for the atom, that modifies the decay of the exited state, especially if the atom frequency is close to the band gap. The population inversion is investigated als well as the emission spectrum. The dynamics is analysed in the context of open quantum systems. Due to the multiple reflections in the photonic crystal, the system has a finite memory that inhibits the Markovian approximation. In the Heisenberg picture the equations of motion for the system variables form a infinite hierarchy of integro-differential equations. To get a closed system, approximations like a weak coupling approximation are needed. The thesis starts with a simple photonic crystal that is amenable to analytic calculations: a one-dimensional photonic crystal, that consists of alternating layers. The Bloch modes inside and the vacuum modes outside a finite crystal are linked with a transformation matrix that is interpreted as a transfer matrix. Formulas for the band structure, the reflection from a semi-infinite crystal, and the local density of states in absorbing crystals are found; defect modes and negative refraction are discussed. The quantum optics section of the work starts with the discussion of three problems, that are related to the full resonance fluorescence problem: a pure dephasing model, the driven atom and resonance fluorescence in free space. In the lowest order of the system-environment coupling, the one-time expectation values for the full problem are calculated analytically and the stationary states are discussed for certain cases. For the calculation of the two time correlation functions and spectra, the additional problem of correlations between the two times appears. In the Markovian case, the quantum regression theorem is valid. In the general case, the fluctuation dissipation theorem can be used instead. The two-time correlation functions are calculated by the two different methods. Within the chosen approximations, both methods deliver the same result. Several plots show the dependence of the spectrum on the parameters. Some examples for squeezing spectra are shown with different approximations. A projection operator method is used to establish two kinds of Markovian expansion with and without time convolution. The lowest order is identical with the lowest order of system environment coupling, but higher orders give different results.
For the first time the transcriptional reprogramming of distinct root cortex cells during the arbuscular mycorrhizal (AM) symbiosis was investigated by combining Laser Capture Mirodissection and Affymetrix GeneChip® Medicago genome array hybridization. The establishment of cryosections facilitated the isolation of high quality RNA in sufficient amounts from three different cortical cell types. The transcript profiles of arbuscule-containing cells (arb cells), non-arbuscule-containing cells (nac cells) of Rhizophagus irregularis inoculated Medicago truncatula roots and cortex cells of non-inoculated roots (cor) were successfully explored. The data gave new insights in the symbiosis-related cellular reorganization processes and indicated that already nac cells seem to be prepared for the upcoming fungal colonization. The mycorrhizal- and phosphate-dependent transcription of a GRAS TF family member (MtGras8) was detected in arb cells and mycorrhizal roots. MtGRAS shares a high sequence similarity to a GRAS TF suggested to be involved in the fungal colonization processes (MtRAM1). The function of MtGras8 was unraveled upon RNA interference- (RNAi-) mediated gene silencing. An AM symbiosis-dependent expression of a RNAi construct (MtPt4pro::gras8-RNAi) revealed a successful gene silencing of MtGras8 leading to a reduced arbuscule abundance and a higher proportion of deformed arbuscules in root with reduced transcript levels. Accordingly, MtGras8 might control the arbuscule development and life-time. The targeting of MtGras8 by the phosphate-dependent regulated miRNA5204* was discovered previously (Devers et al., 2011). Since miRNA5204* is known to be affected by phosphate, the posttranscriptional regulation might represent a link between phosphate signaling and arbuscule development. In this work, the posttranscriptional regulation was confirmed by mis-expression of miRNA5204* in M. truncatula roots. The miRNA-mediated gene silencing affects the MtGras8 transcript abundance only in the first two weeks of the AM symbiosis and the mis-expression lines seem to mimic the phenotype of MtGras8-RNAi lines. Additionally, MtGRAS8 seems to form heterodimers with NSP2 and RAM1, which are known to be key regulators of the fungal colonization process (Hirsch et al., 2009; Gobbato et al., 2012). These data indicate that MtGras8 and miRNA5204* are linked to the sym pathway and regulate the arbuscule development in phosphate-dependent manner.
Lakes are increasingly being recognized as an important component of the global carbon cycle, yet anthropogenic activities that alter their community structure may change the way they transport and process carbon. This research focuses on the relationship between carbon cycling and community structure of primary producers in small, shallow lakes, which are the most abundant lake type in the world, and furthermore subject to intense terrestrial-aquatic coupling due to their high perimeter:area ratio. Shifts between macrophyte and phytoplankton dominance are widespread and common in shallow lakes, with potentially large consequences to regional carbon cycling. I thus compared a lake with clear-water conditions and a submerged macrophyte community to a turbid, phytoplankton-dominated lake, describing differences in the availability, processing, and export of organic and inorganic carbon. I furthermore examined the effects of increasing terrestrial carbon inputs on internal carbon cycling processes. Pelagic diel (24-hour) oxygen curves and independent fluorometric approaches of individual primary producers together indicated that the presence of a submerged macrophyte community facilitated higher annual rates of gross primary production than could be supported in a phytoplankton-dominated lake at similar nutrient concentrations. A simple model constructed from the empirical data suggested that this difference between regime types could be common in moderately eutrophic lakes with mean depths under three to four meters, where benthic primary production is a potentially major contributor to the whole-lake primary production. It thus appears likely that a regime shift from macrophyte to phytoplankton dominance in shallow lakes would typically decrease the quantity of autochthonous organic carbon available to lake food webs. Sediment core analyses indicated that a regime shift from macrophyte to phytoplankton dominance was associated with a four-fold increase in carbon burial rates, signalling a major change in lake carbon cycling dynamics. Carbon mass balances suggested that increasing carbon burial rates were not due to an increase in primary production or allochthonous loading, but instead were due to a higher carbon burial efficiency (carbon burial / carbon deposition). This, in turn, was associated with diminished benthic mineralization rates and an increase in calcite precipitation, together resulting in lower surface carbon dioxide emissions. Finally, a period of unusually high precipitation led to rising water levels, resulting in a feedback loop linking increasing concentrations of dissolved organic carbon (DOC) to severely anoxic conditions in the phytoplankton-dominated system. High water levels and DOC concentrations diminished benthic primary production (via shading) and boosted pelagic respiration rates, diminishing the hypolimnetic oxygen supply. The resulting anoxia created redox conditions which led to a major release of nutrients, DOC, and iron from the sediments. This further transformed the lake metabolism, providing a prolonged summertime anoxia below a water depth of 1 m, and leading to the near-complete loss of fish and macroinvertebrates. Pelagic pH levels also decreased significantly, increasing surface carbon dioxide emissions by an order of magnitude compared to previous years. Altogether, this thesis adds an important body of knowledge to our understanding of the significance of the benthic zone to carbon cycling in shallow lakes. The contribution of the benthic zone towards whole-lake primary production was quantified, and was identified as an important but vulnerable site for primary production. Benthic mineralization rates were furthermore found to influence carbon burial and surface emission rates, and benthic primary productivity played an important role in determining hypolimnetic oxygen availability, thus controlling the internal sediment loading of nutrients and carbon. This thesis also uniquely demonstrates that the ecological community structure (i.e. stable regime) of a eutrophic, shallow lake can significantly influence carbon availability and processing. By changing carbon cycling pathways, regime shifts in shallow lakes may significantly alter the role of these ecosystems with respect to the global carbon cycle.
Die vorliegende Arbeit beschäftigt sich mit einer klassischen aber noch immer zentralen und aktuellen Frage der Evaluationsforschung, der Hinterfragung der Verwendung bzw. Wirksamkeit von Evaluationsverfahren. Vor dem Hintergrund der seit Ende der 1990er Jahre vor allem in Europa starken Zunahme von institutionalisierten Politik-Evaluationsverfahren sowie der zugleich zunehmenden Kritik dieser Verfahren in Wissenschaft und Praxis, untersucht die Arbeit diese Wirksamkeit am Fallbeispiel der Forschungspolitik der Europäischen Union. Aufbauend auf einer Aufarbeitung des Forschungsstandes zur Evaluationsverwendungsforschung und einer Vorstellung des gewählten Politikfeldes sowie der spezifischen Evaluationspraxis, erfolgt dazu eine systematische Gegenüberstellung der zentralen Evaluationsempfehlungen und der Entwicklung im Politikfeld über die vergangenen 15 Jahre. Im Ergebnis kommt die Arbeit zu der Feststellung eines (überraschend) hohen Ausmaßes an Entsprechung der Evaluationsempfehlungen mit der Politikentwicklung im untersuchten Fallbeispiel. Auf der Basis der Untersuchung des Fallbeispiels aber auch unter Heranziehung weiterer empirischer Beiträge in der Literatur ist damit der Behauptung der fehlenden Wirksamkeit der institutionalisierten Evaluation auf die Politikgestaltung klar zu widersprechen. Eine weitergehende Diskussion des Ergebnisses der Fallstudie legt darüber hinaus nahe, dass einige spezifische Faktoren und Bedingungen die Wirksamkeit der Evaluationsverfahren im untersuchten Fallbeispiel positiv zu beeinflussen scheinen. Im Einzelnen sind dies: der Charakter und die Ausprägung der Evaluationsempfehlungen, das spezifische institutionelle Umfeld der Evaluation sowie das spezifische 'politische Klima'. Aus dem Ergebnis lässt sich andererseits aber auch folgern, dass insbesondere im Hinblick auf die Akzeptanzproblematik eine Verstärkung der Bemühungen zur Wahrnehmung der Evaluations-wirksamkeit auf Seiten aller Beteiligten geboten scheint. Die Arbeit stellt hierzu abschließend einige Vorschläge und Ideen zusammen, die diese Wahrnehmung verbessern können.
The Arctic tundra, covering approx. 5.5 % of the Earth’s land surface, is one of the last ecosystems remaining closest to its untouched condition. Remote sensing is able to provide information at regular time intervals and large spatial scales on the structure and function of Arctic ecosystems. But almost all natural surfaces reveal individual anisotropic reflectance behaviors, which can be described by the bidirectional reflectance distribution function (BRDF). This effect can cause significant changes in the measured surface reflectance depending on solar illumination and sensor viewing geometries. The aim of this thesis is the hyperspectral and spectro-directional reflectance characterization of important Arctic tundra vegetation communities at representative Siberian and Alaskan tundra sites as basis for the extraction of vegetation parameters, and the normalization of BRDF effects in off-nadir and multi-temporal remote sensing data. Moreover, in preparation for the upcoming German EnMAP (Environmental Mapping and Analysis Program) satellite mission, the understanding of BRDF effects in Arctic tundra is essential for the retrieval of high quality, consistent and therefore comparable datasets. The research in this doctoral thesis is based on field spectroscopic and field spectro-goniometric investigations of representative Siberian and Alaskan measurement grids. The first objective of this thesis was the development of a lightweight, transportable, and easily managed field spectro-goniometer system which nevertheless provides reliable spectro-directional data. I developed the Manual Transportable Instrument platform for ground-based Spectro-directional observations (ManTIS). The outcome of the field spectro-radiometrical measurements at the Low Arctic study sites along important environmental gradients (regional climate, soil pH, toposequence, and soil moisture) show that the different plant communities can be distinguished by their nadir-view reflectance spectra. The results especially reveal separation possibilities between the different tundra vegetation communities in the visible (VIS) blue and red wavelength regions. Additionally, the near-infrared (NIR) shoulder and NIR reflectance plateau, despite their relatively low values due to the low structure of tundra vegetation, are still valuable information sources and can separate communities according to their biomass and vegetation structure. In general, all different tundra plant communities show: (i) low maximum NIR reflectance; (ii) a weakly or nonexistent visible green reflectance peak in the VIS spectrum; (iii) a narrow “red-edge” region between the red and NIR wavelength regions; and (iv) no distinct NIR reflectance plateau. These common nadir-view reflectance characteristics are essential for the understanding of the variability of BRDF effects in Arctic tundra. None of the analyzed tundra communities showed an even closely isotropic reflectance behavior. In general, tundra vegetation communities: (i) usually show the highest BRDF effects in the solar principal plane; (ii) usually show the reflectance maximum in the backward viewing directions, and the reflectance minimum in the nadir to forward viewing directions; (iii) usually have a higher degree of reflectance anisotropy in the VIS wavelength region than in the NIR wavelength region; and (iv) show a more bowl-shaped reflectance distribution in longer wavelength bands (>700 nm). The results of the analysis of the influence of high sun zenith angles on the reflectance anisotropy show that with increasing sun zenith angles, the reflectance anisotropy changes to azimuthally symmetrical, bowl-shaped reflectance distributions with the lowest reflectance values in the nadir view position. The spectro-directional analyses also show that remote sensing products such as the NDVI or relative absorption depth products are strongly influenced by BRDF effects, and that the anisotropic characteristics of the remote sensing products can significantly differ from the observed BRDF effects in the original reflectance data. But the results further show that the NDVI can minimize view angle effects relative to the contrary spectro-directional effects in the red and NIR bands. For the researched tundra plant communities, the overall difference of the off-nadir NDVI values compared to the nadir value increases with increasing sensor viewing angles, but on average never exceeds 10 %. In conclusion, this study shows that changes in the illumination-target-viewing geometry directly lead to an altering of the reflectance spectra of Arctic tundra communities according to their object-specific BRDFs. Since the different tundra communities show only small, but nonetheless significant differences in the surface reflectance, it is important to include spectro-directional reflectance characteristics in the algorithm development for remote sensing products.
Diese Arbeit befasst sich mit der Synthese und der Charakterisierung von thermoresponsiven Polymeren und ihrer Immobilisierung auf festen Oberflächen als nanoskalige dünne Schichten. Dabei wurden thermoresponsive Polymere vom Typ der unteren kritischen Entmischungstemperatur (engl.: lower critical solution temperature, LCST) verwendet. Sie sind bei niedrigeren Temperaturen im Lösungsmittel gut und nach Erwärmen oberhalb einer bestimmten kritischen Temperatur nicht mehr löslich; d. h. sie weisen bei einer bestimmten Temperatur einen Phasenübergang auf. Als Basismaterial wurden verschiedene thermoresponsive und biokompatible Polymere basierend auf Diethylenglykolmethylethermethacrylat (MEO2MA) und Oligo(ethylenglykol)methylethermethacrylat (OEGMA475, Mn = 475 g/ mol) über frei radikalische Copolymerisation synthetisiert. Der thermoresponsive Phasenübergang der Copolymere wurde in wässriger Lösung und in gequollenen vernetzten dünnen Schichten beobachtet. Außerdem wurde untersucht, inwiefern eine selektive Proteinbindung an geeignete funktionalisierte Copolymere die Phasenübergangstemperatur beeinflusst. Die thermoresponsiven Copolymere wurden über photovernetzbare Gruppen auf festen Oberflächen immobilisiert. Die nötigen lichtempfindlichen Vernetzereinheiten wurden mittels des polymerisierbaren Benzophenonderivates 2 (4 Benzoylphenoxy)ethylmethacrylat (BPEM) in das Copolymer integriert. Dünne Filme der Copolymere mit ca. 100 nm Schichtdicke wurden über Rotationsbeschichtung auf Siliziumwafer aufgeschleudert und anschließend durch Bestrahlung mit UV Licht vernetzt und auf der Oberfläche immobilisiert. Die Filme sind stabiler je größer der Vernetzeranteil und je größer die Molmasse der Copolymere ist. Bei einem Waschprozess nach der Vernetzung wird beispielsweise aus einem Film mit moderater Molmasse und geringem Vernetzeranteil mehr unvernetztes Copolymer ausgewaschen als bei einem höhermolekularen Copolymer mit hohem Vernetzeranteil. Die Quellbarkeit der Polymerschichten wurde mit Ellipsometrie untersucht. Sie ist größer je geringer der Vernetzeranteil in den Copolymeren ist. Schichten aus thermoresponsiven OEG Copolymeren zeigen einen Volumenphasenübergang vom Typ der LCST. Der thermoresponsive Kollaps der Schichten ist komplett reversibel, die Kollapstemperatur kann über die Zusammensetzung der Copolymere eingestellt werden. Für einen Vergleich dieser Eigenschaften mit dem gut charakterisierten und derzeit wohl am häufigsten untersuchten thermoresponsiven Polymer Poly(N-isopropylacrylamid) (PNIPAM) wurden zusätzlich photovernetzte Schichten aus PNIPAM hergestellt und ebenfalls ellipsometrisch vermessen. Im Vergleich zu PNIPAM verläuft der Phasenübergang der Schichten aus den Copolymeren mit Oligo(ethylenglykol)-seitenketten (OEG Copolymere) über einen größeren Temperaturbereich. Mit Licht einer Wellenlänge > 300 nm wurden die photosensitiven Benzophenongruppen selektiv angeregt. Bei der Verwendung kleinerer Wellenlängen vernetzten die Copolymerschichten auch ohne die Anwesenheit der lichtempfindlichen Benzophenongruppen. Dieser Effekt ließ sich zur kontrollierten Immobilisierung und Vernetzung der OEG Copolymere einsetzen. Als weitere Methode zur Immobilisierung der Copolymere wurde die Anbindung über Amidbindungen untersucht. Dazu wurden OEG Copolymere mit dem carboxylgruppenhaltigen 2 Succinyloxyethylmethacrylat (MES) auf mit 3 Aminopropyldimethylethoxysilan (APDMSi) silanisierte Siliziumwafer rotationsbeschichtet, und mit dem oligomeren α, ω Diamin Jeffamin® ED 900 vernetzt. Die Vernetzungsreaktion erfolgte ohne weitere Zusätze durch Erhitzen der Proben. Die Hydrogelschichten waren anschließend stabil und zeigten neben thermoresponsivem auch pH responsives Verhalten. Um zu untersuchen, ob die Phasenübergangstemperatur durch eine Proteinbindung beeinflusst werden kann, wurde ein polymerisierbares Biotinderivat 2 Biotinyl-aminoethylmethacrylat (BAEMA) in das thermoresponsive Copolymer eingebaut. Der Einfluss des biotinbindenen Proteins Avidin auf das thermoresponsive Verhalten des Copolymers in Lösung wurde untersucht. Die spezifische Bindung von Avidin an das biotinylierte Copolymer verschob die Übergangstemperatur deutlich zu höheren Temperaturen. Kontrollversuche zeigten, dass dieses Verhalten auf eine selektive Proteinbindung zurückzuführen ist. Thermoresponsive OEG Copolymere mit photovernetzbaren Gruppen aus BPEM und Biotingruppen aus BAEMA wurden über Rotationsbeschichtung auf Gold- und auf Siliziumoberflächen aufgetragen und durch UV Strahlung vernetzt. Die spezifische Bindung von Avidin an die Copolymerschicht wurde mit Oberflächenplasmonenresonanz und Ellipsometrie untersucht. Die Bindungskapazität der Schichten war umso größer, je kleiner der Vernetzeranteil, d. h. je größer die Maschenweite des Netzwerkes war. Die Quellbarkeit der Schichten wurde durch die Avidinbindung erhöht. Bei hochgequollenen Systemen verursachte eine Mehrfachbindung des tetravalenten Avidins allerdings eine zusätzliche Quervernetzung des Polymernetzwerkes. Dieser Effekt wirkt der erhöhten Quellbarkeit durch die Avidinbindung entgegen und lässt die Polymernetzwerke schrumpfen.
This thesis presents novel ideas and research findings for the Web of Data – a global data space spanning many so-called Linked Open Data sources. Linked Open Data adheres to a set of simple principles to allow easy access and reuse for data published on the Web. Linked Open Data is by now an established concept and many (mostly academic) publishers adopted the principles building a powerful web of structured knowledge available to everybody. However, so far, Linked Open Data does not yet play a significant role among common web technologies that currently facilitate a high-standard Web experience. In this work, we thoroughly discuss the state-of-the-art for Linked Open Data and highlight several shortcomings – some of them we tackle in the main part of this work. First, we propose a novel type of data source meta-information, namely the topics of a dataset. This information could be published with dataset descriptions and support a variety of use cases, such as data source exploration and selection. For the topic retrieval, we present an approach coined Annotated Pattern Percolation (APP), which we evaluate with respect to topics extracted from Wikipedia portals. Second, we contribute to entity linking research by presenting an optimization model for joint entity linking, showing its hardness, and proposing three heuristics implemented in the LINked Data Alignment (LINDA) system. Our first solution can exploit multi-core machines, whereas the second and third approach are designed to run in a distributed shared-nothing environment. We discuss and evaluate the properties of our approaches leading to recommendations which algorithm to use in a specific scenario. The distributed algorithms are among the first of their kind, i.e., approaches for joint entity linking in a distributed fashion. Also, we illustrate that we can tackle the entity linking problem on the very large scale with data comprising more than 100 millions of entity representations from very many sources. Finally, we approach a sub-problem of entity linking, namely the alignment of concepts. We again target a method that looks at the data in its entirety and does not neglect existing relations. Also, this concept alignment method shall execute very fast to serve as a preprocessing for further computations. Our approach, called Holistic Concept Matching (HCM), achieves the required speed through grouping the input by comparing so-called knowledge representations. Within the groups, we perform complex similarity computations, relation conclusions, and detect semantic contradictions. The quality of our result is again evaluated on a large and heterogeneous dataset from the real Web. In summary, this work contributes a set of techniques for enhancing the current state of the Web of Data. All approaches have been tested on large and heterogeneous real-world input.
Da geologische Störungen können als Grundwasserleiter, -Barrieren oder als gemischte leitende /stauende Fluidsysteme wirken. Aufgrund dessen können Störungen maßgeblich den Grundwasserfluss im Untergrund beeinflussen, welcher deutliche Veränderungen des tiefen thermischen Feldes bewirken kann. Grundwasserdynamik und Temperaturveränderungen sind wiederum entscheidende Faktoren für die Exploration geothermischer Energie. Diese Studie untersuchte den Einfluss von Störungen auf das Fluidsystem und das thermische Feld im Untergrund. Sie erforschte die physikalischen Prozesse, welche das Fluidverhalten und die Temperaturverteilung in Störungen und in den umgebenden Gesteinen. Dazu wurden 3D Finite Elemente Simulationen des gekoppelten Fluid und Wärmetransports für synthetische sowie reale Modelszenarien auf unterschiedlichen Skalen durchgeführt. Um den Einfluss einer schräg einfallenden Störung systematisch durch die schrittweise Veränderung der hydraulischen Öffnungsweite und der Permeabilität, zu untersuchen, wurde ein klein-skaliges synthetisches Modell entwickelt. Ein inverser linearer Zusammenhang wurde festgestellt, welcher zeigt, dass sich die Fluidgeschwindigkeit in der Störung jeweils um ~1e-01 m/s verringert, wenn die Öffnungsweite der Störung um jeweils eine Magnitude vergrößert wird. Ein hoher Permeabilitätskontrast zwischen Störung und umgebender Matrix begünstigt die Fluidadvektion hin zur Störung und führt zu ausgeprägten Druck- und Temperaturveränderungen innerhalb und um die Störung herum. Bei geringem Permeabilitätskontrast zwischen Störung und umgebendem Gestein findet hingegen kein Fluidfluss in der Störung statt, wobei das hydrostatische Druck- sowie das Temperaturfeld unverändert bleiben. Auf Grundlage der synthetischen Modellierungsergebnisse wurde der Einfluss von Störungen auf einer größeren Skala anhand eines komplexeren (realen) geologischen Systems analysiert. Dabei handelt es sich um ein 3D Modell des Geothermiestandortes Groß Schönebeck, der ca. 40 km nördlich von Berlin liegt. Die Integration von einer permeablen und drei impermeablen Hauptstörungen, zeigte unterschiedlich starke Einflüsse auf Fluidzirkulation, Temperatur – und Druckfeld. Die modellierte konvektive Zirkulation in der permeablen Störung verändert das thermische Feld stark (bis zu 15 K). In den gering durchlässigen Störungen wird die Wärme ausschließlich durch Diffusion geleitet. Der konduktive Wärmetransport beeinflusst das thermische Feld nicht, bewirkt jedoch lokale Veränderungen des hydrostatischen Druckfeldes. Um den Einfluss großer Störungszonen mit kilometerweitem vertikalen Versatz auf das geothermische Feld der Beckenskala zu untersuchen, wurden gekoppelte Fluid- und Wärmetransportsimulationen für ein 3D Strukturmodell des Gebietes Brandenburg durchgeführt (Noack et al. 2010; 2013). Bezüglich der Störungspermeabilität wurden verschiedene geologische Szenarien modelliert, von denen zwei Endgliedermodelle ausgewertet wurden. Die Ergebnisse zeigten, dass die undurchlässigen Störungen den Fluidfluss nur lokal beeinflussen. Da sie als hydraulische Barrieren wirken, wird der Fluidfluss mir sehr geringen Geschwindigkeiten entlang der Störungen innerhalb eines Bereichs von ~ 1 km auf jeder Seite umgelenkt. Die modellierten lokalen Veränderungen des Grundwasserzirkulationssystems haben keinen beobachtbaren Effekt auf das Temperaturfeld. Hingegen erzeugen permeable Störungszonen eine ausgeprägte thermische Signatur innerhalb eines Einflussbereichs von ~ 2.4-8.8 km in -1000 m Tiefe und ~6-12 km in -3000 m Tiefe. Diese thermische Signatur, in der sich kältere und wärmere Temperaturbereiche abwechseln, wird durch auf- und abwärts gerichteten Fluidfluss innerhalb der Störung verursacht, der grundsätzlich durch existierende Gradienten in der hydraulischen Druckhöhe angetrieben wird. Alle Studien haben gezeigt, dass Störungen einen beachtlichen Einfluss auf den Fluid-, und Wärmefluss haben. Es stellte sich heraus, dass die Permeabilität in der Störung und in den umgebenden geologischen Schichten so wie der spezifische geologische Rahmen entscheidende Faktoren in der Ausbildung verschiedener Wärmetransportmechanismen sind, die sich in Störungen entwickeln können. Die von permeablen Störungen verursachten Temperaturveränderungen können lokal, jedoch groß sein, genauso wie die durch hydraulisch leitende und nichtleitende Störungen hervorgerufenen Veränderungen des Fluidystems. Letztlich haben die Simulationen für die unterschiedlich skalierten Modelle gezeigt, dass die Ergebnisse sich nicht aufeinander übertragen lassen und dass es notwendig ist, jeden geologischen Rahmen hinsichtlich Konfiguration und Größenskala gesondert zu betrachten. Abschließend hat diese Studie demonstriert, dass die Betrachtung von Störungen in 3D Finiten Elementen Modellen für die Simulation von gekoppeltem Fluid- und Wärmetransport auf unterschiedlichen Skalen möglich ist. Da diese Art von numerischen Simulationen sowohl die geologische Struktur des Untergrunds sowie die im Erdinnern ablaufenden physikalischen Prozesse integriert, können sie einen wertvollen Beitrag leisten, indem sie Feld- und Laborgestützte Untersuchungen vervollständigen.
The supercapacitor is one of the most important energy storage devices as its construction allows for addressing many of the drawbacks related to batteries, but the low energy density of current systems is a major issue. In this doctoral dissertation, with a view to attaining high energy density supercapacitor systems that can be comparable to those for batteries, new heteroatom-containing carbons in the form of particles and three-dimensional films were investigated. A nitrogen-containing material, acrodam, was chosen as the carbon precursor due to the inexpensiveness, high carbonization yield, oligomerizability, etc. The carbon particles were prepared from acrodam together with caesium acetate as a meltable flux agent, and disclosed excellent properties in hydroquinone-loaded sulphuric acid electrolyte with high energy densities (up to 133.0 Wh kg–1) and sufficient cycle stabilities. These properties are already now comparable to those of batteries. Besides, conductive carbon three-dimensional films were fabricated using acrodam oligomer as the precursor by the inexpensive spin coating method. The films were found to be homogeneous, flat, void- and crack-free, and high conductivities (up to 334 S cm–1) could be obtained at the carbonization temperature of 1000 ºC. Furthermore, a porous carbon three-dimensional film could be formed using an organic template at the first attempt. This finding demonstrates the film’s potentiality for various applications such as supercapacitor electrode; the essential absence of contact resistance within the network should contribute to effective transportation of electron within the electrode. The progress made in this dissertation will open a new way to further enhancement of energy density for supercapacitor as well as other applications that exceeds the current properties.
Zur Versorgung ausländischer Märkte bedienen sich Unternehmen unterschiedlicher Versorgungsformen. Die proximity-concentration trade-off-Literatur betrachtet die Wahl zwischen Export und Auslandsproduktion und erklärt die Entstehung von internationalem Handel und horizontalen ausländischen Direktinvestitionen. Das Standardmodell von Brainard (1993) integriert die Auslandsproduktion als alternative Versorgungsform zum Handel in ein allgemeines Gleichgewichtsmodell mit zwei Ländern, monopolistischer Konkurrenz, steigenden Skalenerträgen und Transportkosten. Im Gleichgewicht versorgen Unternehmen ausländische Märkte entweder durch Exporte oder eine Auslandsproduktion. Die real zu beobachtende Ko-Existenz von internationalem Handel und ausländischen Direktinvestitionen auf der Unternehmensebene kann mit diesem Modell nicht erklärt werden. Im Rahmen dieser Arbeit wird die Exportplattform (EP) als mögliche Antwort auf dieses Phänomen herangezogen. Eine Exportplattform ist eine Auslandsproduktion, durch die nicht nur der lokale Auslandsmarkt, sondern auch Drittländer versorgt werden. Im modelltheoretischen Teil dieser Arbeit wird ein partialanalytisches EP-Modell formuliert, dass auf Brainard (1993) aufbaut. Dabei wird ihr Modell um eine Mehr-Länder-Welt mit heterogener Verteilungsstruktur erweitert und die Versorgungsalternative der EP-Exporte nach dem Beispiel von Neary (2002) integriert. Durch die analytische Lösung des partiellen Gleichgewichts lässt sich die substitutive Beziehung zwischen Heimatexporten, Auslandsproduktion und EP-Exporten aufzeigen. Ferner kann die Wirkung der Versorgungskosten auf die Versorgungswahl analysiert werden. Dabei wird neben der analytischen Modellbeschreibung besonders auf die Gleichgewichtsbestimmung und die Existenz der Gleichgewichte eingegangen. Aufbauend auf den analytisch abzuleitenden Hypothesen wird das EP-Modell ferner einem empirischen Signifikanztest unterzogen. Unter Anwendung von nicht-linearen Regressionsverfahren wird die Wahl zwischen EP-Exporten und Auslandsproduktion, zwischen EP- und Heimatexporten sowie zwischen EP-Exporten und der EP-Produktion separat geschätzt. Hierfür wird auf Daten der Automobilindustrie zurückgegriffen, welche die regionalen PKW-Produktions- und -Absatzdaten sämtlicher Automobilhersteller in Osteuropa, Asien und Ozeanien umfassen.
Within a research project about future sustainable water management options in the Elbe River basin, quasi-natural discharge scenarios had to be provided. The semi-distributed eco-hydrological model SWIM was utilised for this task. According to scenario simulations driven by the stochastical climate model STAR, the region would get distinctly drier. However, this thesis focuses on the challenge of meeting the requirement of high model fidelity even for smaller sub-basins. Usually, the quality of the simulations is lower at inner points than at the outlet. Four research paper chapters and the discussion chapter deal with the reasons for local model deviations and the problem of optimal spatial calibration. Besides other assessments, the Markov Chain Monte Carlo method is applied to show whether evapotranspiration or precipitation should be corrected to minimise runoff deviations, principal component analysis is used in an unusual way to evaluate local precipitation alterations by land cover changes, and remotely sensed surface temperatures allow for an independent view on the evapotranspiration landscape. The overall insight is that spatially explicit hydrological modelling of such a large river basin requires a lot of local knowledge. It probably needs more time to obtain such knowledge as is usually provided for hydrological modelling studies.
In dieser Dissertation erfolgt eine Analyse des Schutzes von Biodiversität durch Payments for Environmental Services (PES) und, insbesondere im empirischen Teil, innerhalb des Ansatzes Reducing Emissions from Deforestation and Forest Degradation plus (REDDplus). Die Anwendung von PES-Programmen zum Schutz von Biodiversität gewinnt im umweltpolitischen Bereich immer mehr an Bedeutung. Gleichzeitig ist die Umsetzung solcher Schutzprogramme jedoch mit erheblichen Transaktionskosten und damit der Gefahr von Ineffizienzen verbunden. Die Möglichkeit der Bündelung von Biodiversität mit einer weiteren Ökosystemleistung, hier der Speicherung von Kohlenstoffdioxid, wird hinsichtlich der Wirkungen auf die Schutzniveaus beider Ökosystemleistungen und der Veränderung der Produktionsweise des landwirtschaftlichen Sektors in einem monopsonistischen Modelansatz analysiert. Durch die formale Analyse zeigt sich, dass für einen effizienteren Schutz der beiden Ökosystemleistungen economies of scope bei den Transaktionskosten mit der Bündelung von PES-Programmen realisiert werden müssen. Ein Beispiel für die praktische Umsetzung von Payments for Environmental Services ist der REDDplus-Ansatz. Das Ziel ist die Reduzierung von Treibhausgasemissionen durch den Erhalt und die nachhaltige Bewirtschaftung von tropischen Wäldern, aber auch der Schutz von Biodiversität. Innerhalb des empirischen Teiles der Dissertation wird untersucht, inwiefern es durch die Verfolgung beider Ziele zur Realisierung von economies of scope bei den Transaktionskosten kommt. In die Analyse werden sechs Länder (Costa-Rica, Indonesien, Mexiko, Kambodscha, Peru und Vietnam) einbezogen. Die Analyse erfolgt auf der Grundlage von Szenarien, welche mit Hilfe der Readiness Proposals der Länder für den Zeitraum von 2008 bis 2030 erstellt wurden. Anhand der Ergebnisse kann gezeigt werden, dass es nicht automatisch durch die Zusammenlegung von PES-Programmen zu einer Realisierung von economies of scope kommt. Eine Bündelung solcher Programme ist daher nicht in allen Phasen ihrer Umsetzung ratsam.
Despite the increased attention devoted to sexual aggression among young people in the international scientific literature, Brazil has little research on the subject exclusively among this group. There is evidence that sexual aggression and victimization may start early. Identifying the magnitude and factors that increase the chance for the onset and persistence of sexual victimization are the first steps for prevention efforts among this group. Using both cross-sectional and prospective analyses, this study examined the prevalence of, and vulnerability factors for sexual aggression and victimization in female and male college students (N = 742; M = 20.1 years) in Brazil, of whom a subgroup (n = 354) took part in two measurements six months apart. At Time 1, a Portuguese version of the Short Form of the Sexual Experiences Survey (Koss et al., 2007) was administered to collect information from men and women as both victims and perpetrators of sexual aggression since the age of 14. The students were also asked to provide information on their cognitive representations (sexual scripts) of a consensual sexual encounter, their actual sexual behavior, use of pornography, and experiences of child abuse. At Time 2, the same items from the SES were presented again to assess the incidence of sexual aggression in the 6-month period since T1. The overall prevalence rate of victimization was 27% among men and 29% among women. In contrast, perpetration rates were significantly higher among men (33.7%) than among women (3%). Confirming the hypotheses, cognitive (i.e., risky sexual scripts, normative beliefs), behavioral (i.e., pornography use, sexual behavior patterns) and biographical (i.e., childhood abuse) risk factors were linked to male sexual aggression and to male and female victimization both cross-sectionally and longitudinally with the path models analyses demonstrating good fit with the data. The results supported: a) the role of the sexual script for a first consensual sexual encounter as an underlying factor of real sexual behavior and sexual victimization or perpetration; b) the role of pornography as “inputs” for sexual scripts, increasing indirectly the risk for victimization, and directly and indirectly the risk for perpetration; c) the direct and indirect link between childhood experiences of (sexual) abuse and male sexual aggression and victimization mediated by sexual behavior; and d) the direct link between child sexual abuse and sexual victimization among women. Few gender differences were found in the victimization model. The findings challenge societal beliefs that sexual aggression is restricted to groups with low socio-economic status and that men are unlikely to be sexually coerced. The disparity between male victimization and female perpetration rates is discussed based on traditional gender roles in Brazil. This study is also the first prospective investigation of risk factors for sexual aggression and victimization in Brazil, demonstrating the role of behavioral, cognitive and biographical factors that increase the vulnerability among college students.
A detailed description of the characteristics of antimicrobial peptides (AMPs) is highly demanded, since the resistance against traditional antibiotics is an emerging problem in medicine. They are part of the innate immune system in every organism, and they are very efficient in the protection against bacteria, viruses, fungi and even cancer cells. Their advantage is that their target is the cell membrane, in contrast to antibiotics which disturb the metabolism of the respective cell type. This allows AMPs to be more active and faster. The lack of an efficient therapy for some cancer types and the evolvement of resistance against existing antitumor agents make AMPs promising in cancer therapy besides being an alternative to traditional antibiotics. The aim of this work was the physical-chemical characterization of two fragments of LL-37, a human antimicrobial peptide from the cathelicidin family. The fragments LL-32 and LL-20 exhibited contrary behavior in biological experiments concerning their activity against bacterial cells, human cells and human cancer cells. LL-32 had even a higher activity than LL-37, while LL-20 had almost no effect. The interaction of the two fragments with model membranes was systematically studied in this work to understand their mode of action. Planar lipid films were mainly applied as model systems in combination with IR-spectroscopy and X-ray scattering methods. Circular Dichroism spectroscopy in bulk systems completed the results. In the first approach, the structure of the peptides was determined in aqueous solution and compared to the structure of the peptides at the air/water interface. In bulk, both peptides are in an unstructured conformation. Adsorbed and confined to at the air-water interface, the peptides differ drastically in their surface activity as well as in the secondary structure. While LL-32 transforms into an α-helix lying flat at the water surface, LL-20 stays partly unstructured. This is in good agreement with the high antimicrobial activity of LL-32. In the second approach, experiments with lipid monolayers as biomimetic models for the cell membrane were performed. It could be shown that the peptides fluidize condensed monolayers of negatively charged DPPG which can be related to the thinning of a bacterial cell membrane. An interaction of the peptides with zwitterionic PCs, as models for mammalian cells, was not clearly observed, even though LL-32 is haemolytic. In the third approach, the lipid monolayers were more adapted to the composition of human erythrocyte membranes by incorporating sphingomyelin (SM) into the PC monolayers. Physical-chemical properties of the lipid films were determined and the influence of the peptides on them was studied. It could be shown that the interaction of the more active LL-32 is strongly increased for heterogeneous lipid films containing both gel and fluid phases, while the interaction of LL-20 with the monolayers was unaffected. The results indicate an interaction of LL-32 with the membrane in a detergent-like way. Additionally, the modelling of the peptide interaction with cancer cells was performed by incorporating some negatively charged lipids into the PC/SM monolayers, but the increased charge had no effect on the interaction of LL-32. It was concluded, that the high anti-cancer activity of the peptide originates from the changed fluidity of cell membrane rather than from the increased surface charge. Furthermore, similarities to the physical-chemical properties of melittin, an AMP from the bee venom, were demonstrated.
Cloud computing is a model for enabling on-demand access to a shared pool of computing resources. With virtually limitless on-demand resources, a cloud environment enables the hosted Internet application to quickly cope when there is an increase in the workload. However, the overhead of provisioning resources exposes the Internet application to periods of under-provisioning and performance degradation. Moreover, the performance interference, due to the consolidation in the cloud environment, complicates the performance management of the Internet applications. In this dissertation, we propose two approaches to mitigate the impact of the resources provisioning overhead. The first approach employs control theory to scale resources vertically and cope fast with workload. This approach assumes that the provider has knowledge and control over the platform running in the virtual machines (VMs), which limits it to Platform as a Service (PaaS) and Software as a Service (SaaS) providers. The second approach is a customer-side one that deals with the horizontal scalability in an Infrastructure as a Service (IaaS) model. It addresses the trade-off problem between cost and performance with a multi-goal optimization solution. This approach finds the scale thresholds that achieve the highest performance with the lowest increase in the cost. Moreover, the second approach employs a proposed time series forecasting algorithm to scale the application proactively and avoid under-utilization periods. Furthermore, to mitigate the interference impact on the Internet application performance, we developed a system which finds and eliminates the VMs suffering from performance interference. The developed system is a light-weight solution which does not imply provider involvement. To evaluate our approaches and the designed algorithms at large-scale level, we developed a simulator called (ScaleSim). In the simulator, we implemented scalability components acting as the scalability components of Amazon EC2. The current scalability implementation in Amazon EC2 is used as a reference point for evaluating the improvement in the scalable application performance. ScaleSim is fed with realistic models of the RUBiS benchmark extracted from the real environment. The workload is generated from the access logs of the 1998 world cup website. The results show that optimizing the scalability thresholds and adopting proactive scalability can mitigate 88% of the resources provisioning overhead impact with only a 9% increase in the cost.
Measuring the metabolite profile of plants can be a strong phenotyping tool, but the changes of metabolite pool sizes are often difficult to interpret, not least because metabolite pool sizes may stay constant while carbon flows are altered and vice versa. Hence, measuring the carbon allocation of metabolites enables a better understanding of the metabolic phenotype. The main challenge of such measurements is the in vivo integration of a stable or radioactive label into a plant without perturbation of the system. To follow the carbon flow of a precursor metabolite, a method is developed in this work that is based on metabolite profiling of primary metabolites measured with a mass spectrometer preceded by a gas chromatograph (Wagner et al. 2003; Erban et al. 2007; Dethloff et al. submitted). This method generates stable isotope profiling data, besides conventional metabolite profiling data. In order to allow the feeding of a 13C sucrose solution into the plant, a petiole and a hypocotyl feeding assay are developed. To enable the processing of large numbers of single leaf samples, their preparation and extraction are simplified and optimised. The metabolite profiles of primary metabolites are measured, and a simple relative calculation is done to gain information on carbon allocation from 13C sucrose. This method is tested examining single leaves of one rosette in different developmental stages, both metabolically and regarding carbon allocation from 13C sucrose. It is revealed that some metabolite pool sizes and 13C pools are tightly associated to relative leaf growth, i.e. to the developmental stage of the leaf. Fumaric acid turns out to be the most interesting candidate for further studies because pool size and 13C pool diverge considerably. In addition, the analyses are also performed on plants grown in the cold, and the initial results show a different metabolite pool size pattern across single leaves of one Arabidopsis rosette, compared to the plants grown under normal temperatures. Lastly, in situ expression of REIL genes in the cold is examined using promotor-GUS plants. Initial results suggest that single leaf metabolite profiles of reil2 differ from those of the WT.
This thesis rests on two large Active Galactic Nuclei (AGNs) surveys. The first survey deals with galaxies that host low-level AGNs (LLAGN) and aims at identifying such galaxies by quantifying their variability. While numerous studies have shown that AGNs can be variable at all wavelengths, the nature of the variability is still not well understood. Studying the properties of LLAGNs may help to understand better galaxy evolution, and how AGNs transit between active and inactive states. In this thesis, we develop a method to extract variability properties of AGNs. Using multi-epoch deep photometric observations, we subtract the contribution of the host galaxy at each epoch to extract variability and estimate AGN accretion rates. This pipeline will be a powerful tool in connection with future deep surveys such as PANSTARS. The second study in this thesis describes a survey of X-ray selected AGN hosts at redshifts z>1.5 and compares them to quiescent galaxies. This survey aims at studying environments, sizes and morphologies of star-forming high-redshift AGN hosts in the COSMOS Survey at the epoch of peak AGN activity. Between redshifts 1.5<z<3.8, the COSMOS HST/ACS imaging probes the UV regime, where separating the AGN flux from its host galaxy is very challenging. Nevertheless, we successfully derived the structural properties of 249 AGN hosts using two-dimensional surface-brightness profile fitting with the GALFIT package. This is the largest sample of AGN hosts at redshift z>1.5 to date. We analyzed the evolution of structural parameters of AGN and non-AGN host galaxies with redshift, and compared their disturbance rates to identify the more probable AGN triggering mechanism in the 43.5<log_10 L_X<45 luminosity range. We also conducted mock AGN and quiescent galaxies observations to determine errors and corrections for the derived parameters. We find that the size-absolute magnitude relations of AGN hosts and non-AGN galaxies are very similar, with estimated mean sizes in both samples decreasing by ~50% between redshifts z=1.5 and z=3.5. Morphological classification of both active and quiescent galaxies shows that the majority of the AGN host galaxies are disc-dominated, with disturbance rates that are significantly lower than among the non-AGN galaxies. Such a finding suggests that Major Mergers are probably not responsible for triggering AGN accretion in most of these galaxies. Other secular mechanisms should therefore be responsible.
The nutrient exchange between plant and fungus is the key element of the arbuscular mycorrhizal (AM) symbiosis. The fungus improves the plant’s uptake of mineral nutrients, mainly phosphate, and water, while the plant provides the fungus with photosynthetically assimilated carbohydrates. Still, the knowledge about the mechanisms of the nutrient exchange between the symbiotic partners is very limited. Therefore, transport processes of both, the plant and the fungal partner, are investigated in this study. In order to enhance the understanding of the molecular basis underlying this tight interaction between the roots of Medicago truncatula and the AM fungus Rhizophagus irregularis, genes involved in transport processes of both symbiotic partners are analysed here. The AM-specific regulation and cell-specific expression of potential transporter genes of M. truncatula that were found to be specifically regulated in arbuscule-containing cells and in non-arbusculated cells of mycorrhizal roots was confirmed. A model for the carbon allocation in mycorrhizal roots is suggested, in which carbohydrates are mobilized in non-arbusculated cells and symplastically provided to the arbuscule-containing cells. New insights into the mechanisms of the carbohydrate allocation were gained by the analysis of hexose/H+ symporter MtHxt1 which is regulated in distinct cells of mycorrhizal roots. Metabolite profiling of leaves and roots of a knock-out mutant, hxt1, showed that it indeed does have an impact on the carbohydrate balance in the course of the symbiosis throughout the whole plant, and on the interaction with the fungal partner. The primary metabolite profile of M. truncatula was shown to be altered significantly in response to mycorrhizal colonization. Additionally, molecular mechanisms determining the progress of the interaction in the fungal partner of the AM symbiosis were investigated. The R. irregularis transcriptome in planta and in extraradical tissues gave new insight into genes that are differentially expressed in these two fungal tissues. Over 3200 fungal transcripts with a significantly altered expression level in laser capture microdissection-collected arbuscules compared to extraradical tissues were identified. Among them, six previously unknown specifically regulated potential transporter genes were found. These are likely to play a role in the nutrient exchange between plant and fungus. While the substrates of three potential MFS transporters are as yet unknown, two potential sugar transporters are might play a role in the carbohydrate flow towards the fungal partner. In summary, this study provides new insights into transport processes between plant and fungus in the course of the AM symbiosis, analysing M. truncatula on the transcript and metabolite level, and provides a dataset of the R. irregularis transcriptome in planta, providing a high amount of new information for future works.
Adipositas gilt seit einigen Jahren als eine der häufigsten chronischen Erkrankungen des Kindes- und Jugendalters. Welche Faktoren zu einer erfolgreichen Behandlung der Adipositas im Kindes- und Jugendalter führen, sind jedoch noch immer nicht ausreichend geklärt. Ein wichtiger – bisher jedoch weitgehend unbeachteter – Faktor, welcher möglicherweise wegweisend für den Therapieverlauf sein kann, ist das subjektive Krankheitskonzept der betroffenen Kinder. Das bedeutsamste theoretische Modell, welches den Einfluss der individuellen Krankheitsvorstellungen auf den Regulationsprozess eines Menschen im Umgang mit Erkrankungen beschreibt, ist das Common Sense Model of Illness Representation (CSM) von Howard Leventhal. Ziel der vorliegenden Arbeit war es die subjektiven Krankheitskonzepte adipöser Kinder zu erfassen und ihren Einfluss auf den Regulationsprozess zu analysieren. In einer ersten Untersuchung wurde mittels Daten von 168 adipösen Kindern im Alter von 8 bis 12 Jahren zunächst ein Fragebogen zur Erfassung der subjektiven Krankheitskonzepte entwickelt. Die Ergebnisse weisen darauf hin, dass der Fragebogen als reliabel und valide eingeschätzt werden kann. Mit Hilfe dieses Fragebogens konnte nachgewiesen werden, dass adipöse Kinder Konstrukte über ihre Erkrankung haben, welche in eigenständigen Dimensionen gespeichert werden. Die gefundenen initialen Krankheitskonzepte adipöser Kinder ergeben ein homogenes erwartungskonformes Bild. In einer zweiten Untersuchung wurden anschließend die subjektiven Krankheitskonzepte adipöser Kinder, die Bewältigungsstrategien sowie gesundheits- und krankheitsrelevante Kriteriumsvariablen untersucht. Die Befragungen erfolgten vor Beginn einer stationären Reha (T1), am Ende der Reha (T2) sowie sechs Monate nach Reha-Ende (T3). Von 107 Kindern liegen Daten zu allen drei Messzeitpunkten vor. Es konnte ein Zusammenhang zwischen Krankheitskonzepten, Bewältigungsstrategien und spezifischen Kriteriumsvariablen bei adipösen Kindern nachgewiesen werden. Die Analyse der Wirkzusammenhänge konnte zeigen, dass die kindlichen Krankheitskonzepte – neben den indirekten Einflüssen über die Bewältigungsstrategien – die Kriteriumsvariablen vor allem auch direkt beeinflussen können. Der Einfluss der initialen Krankheitskonzepte adipöser Kinder konnte hierbei sowohl im querschnittlichen als auch im längsschnittlichen Design bestätigt werden. Zudem konnten vielfältige Einflüsse der Veränderung der subjektiven Krankheitskonzepte während der Therapie gefunden werden. Die Veränderungen der Krankheitskonzepte wirken sowohl mittelfristig auf die individuellen Bewältigungsstrategien am Ende der Reha als auch längerfristig auf die adipositasspezifischen Kriteriumsvariablen Gewicht, Ernährung, Bewegung und Lebensqualität. Die Befunde stärken die Relevanz und das Potential der zielgerichteten Modifikation adaptiver bzw. maladaptiver Krankheitskonzepte innerhalb der stationären Therapie der kindlichen Adipositas. Zudem konnte bestätigt werden, dass subjektive Krankheitskonzepte und ihre Veränderung innerhalb der Therapie einen relevanten Beitrag zur Vorhersage des kindlichen Therapieerfolgs über einen längerfristigen Zeitraum leisten können.
Challenging Khmer citizenship : minorities, the state, and the international community in Cambodia
(2013)
The idea of a distinctly ‘liberal’ form of multiculturalism has emerged in the theory and practice of Western democracies and the international community has become actively engaged in its global dissemination via international norms and organizations. This thesis investigates the internationalization of minority rights, by exploring state-minority relations in Cambodia, in light of Will Kymlicka’s theory of multicultural citizenship. Based on extensive empirical research, the analysis explores the situation and aspirations of Cambodia’s ethnic Vietnamese, highland peoples, Muslim Cham, ethnic Chinese and Lao and the relationships between these groups and the state. All Cambodian regimes since independence have defined citizenship with reference to the ethnicity of the Khmer majority and have - often violently - enforced this conception through the assimilation of highland peoples and the Cham and the exclusion of ethnic Vietnamese and Chinese. Cambodia’s current constitution, too, defines citizenship ethnically. State-sponsored Khmerization systematically privileges members of the majority culture and marginalizes minority members politically, economically and socially. The thesis investigates various international initiatives aimed at promoting application of minority rights norms in Cambodia. It demonstrates that these initiatives have largely failed to accomplish a greater degree of compliance with international norms in practice. This failure can be explained by a number of factors, among them Cambodia’s neo-patrimonial political system, the geo-political fears of a ‘minoritized’ Khmer majority, the absence of effective regional security institutions, the lack of minority access to political decision-making, the significant differences between international and Cambodian conceptions of modern statehood and citizenship and the emergence of China as Cambodia’s most important bilateral donor and investor. Based on this analysis, the dissertation develops recommendations for a sequenced approach to minority rights promotion, with pragmatic, less ambitious shorter-term measures that work progressively towards achievement of international norms in the longer-term.
Die professionalisierte Kommunikation komplexer Gebilde wie Staaten und Nationen, die ihre Hinwendung politischer Fragestellungen in die Sphären von Image und Einfluss verlegt, kommt vor dem Hintergrund wachsenden Wettbewerbs an der Bedeutung der Reputation nicht vorbei. Denn neben ihrer ökonomischen Bedeutung legitimiert Reputation als mittel- oder langfristiges öffentliches Ansehen, das ihren Trägern Definitions- und Überzeugungsmacht verschafft, Macht- und Herrschaftspositionen. In einer mediatisierten Gesellschaft wächst die Bedeutung der Kommunikation mit der Öffentlichkeit sowohl für Erwerb und Erhalt von Reputation – wie auch für deren Aberkennung. Dabei spielt eine zunehmende Skandalisierung als Eigenheit der Mediengesellschaft eine Rolle, die eine erhöhte Fragilisierung der Reputation zur Folge hat und als wirksamster Mechanismus bei der Aberkennung von Reputation gilt, wie das Beispiel der dänischen „Karikaturen-Affäre“ veranschaulicht. In einer kommunikativ schnelllebigen Welt, zunehmend frei verfügbarer Information, geistern durch die Außenministerien des Global Village Begriffe wie Public Diplomacy, Nation Branding, Country Branding oder Place Branding, deren gemeinsamer Nenner zunächst die nach außen gerichtete Kommunikation ist. Aber schon die Frage nach Absender und Adressat, nach Akteur und Rezipient, Botschaften und Zielgruppen verweist auf die Komplexität der Kommunikation eines Landes. Ziel der Untersuchung ist es in den Kommunikationsbemühungen von Ländern, Faktoren zu identifizieren, die Image und Reputation nachhaltig beeinflussen können. Dabei stehen die folgenden Fragen im Mittelpunkt der Untersuchung: Wie werden Länder wahrgenommen und Reputation gebildet? Können die Bezugsgruppen eines Landes durch die Stakeholdertheorie (Freeman 1984) beschrieben werden – und wenn ja, welche Konsequenzen hat eine solche Berücksichtigung der Anspruchs- und Adressatengruppen auf die Kommunikation eines Landes? Welche Aspekte der theoretischen Ansätze können für die Kommunikation von Ländern als zentral bewertet werden? Und schließlich: Kann die Reflexion durch die Praxis, am Fallbeispiel der Schweiz, die Relevanz der eruierten Aspekte bestätigen bzw. um weitere Aspekte ergänzen und können auf dieser Grundlage Erfolgsfaktoren identifiziert und geeignete Instrumente für die Reputationskommunikation aufgezeigt werden?
Die kumulative Dissertation zur Projektdidaktik trägt den Titel „Von der Konzeption zur Praxis: Zur Entwicklung der Projektdidaktik am Oberstufen-Kolleg Bielefeld und ihre Impulsgebung und Modellbildung für das deutsche Regelschulwesen“. Die Dissertation versteht sich als beispielgebende Umsetzung und Implementierung der Projektdidaktik für das Regelschulsystem. Auf der Basis von 22 bereits erschienenen Publikationen und einer Monographie werden mit fünf methodischen Zugriffen (bildungshistorisch, dichte Beschreibung, Aktionsforschung, empirische Untersuchung an Regelschulen und Implementierungsforschung, s. Kapitel 1) in sieben Kapiteln (2- 8) des systematischen ersten Teils die Entwicklung der Unterrichtsform Projektunterricht in der BRD, Projektbegriff und Weiterentwicklung des Konzepts, Methodik, Bewertung sowie Organisation des Projektunterrichts am Oberstufen-Kolleg, der Versuchsschule des Landes NRW, in Auseinandersetzung mit der allgemeinen Projektdidaktik dargestellt sowie Formen und Verfahren der erprobten Implementierung in das Regelschulsystem präsentiert.
Ein Schlusskapitel (9) fasst die Ergebnisse zusammen. Im umfangreichen Anhang finden sich verschiedene Publikationen zu Aspekten der Projektdidaktik, auf die der systematische Teil jeweils Bezug nimmt.
Die bildungshistorische Analyse (Kapitel 2) untersucht das Verhältnis von pädagogischer Theorie und schulischer Praxis, die weder in Literatur und noch in Praxis genügend verbunden sind. Nach der Rezeption der gut erforschten Konzeptgeschichte pädagogischer Theorie in Anlehnung an Dewey und Kilpatrick wird durch eine erste Analyse der „Praxisgeschichte“ des Projektunterrichts auf ein Forschungsdesiderat hingewiesen, dies auch um die Projektpraxis am Oberstufen-Kolleg in Beziehung zu der in den Regelschulen setzen zu können. Dabei wurden seit 1975 sechs Entwicklungslinien herausgearbeitet: Start, Krise und ihre Überwindung durch Öffnung und Vernetzung (1975-1990), didaktisch-methodische Differenzierung und Notwendigkeit von Professionalisierung (ab 1990) sowie Schulentwicklung und Institutionalisierung (seit Ende der 1990er Jahre).
Projektunterricht besteht am Oberstufen-Kolleg seit der Gründung 1974 als fest eingerichtete Unterrichtsform (seit 2002 zweimal jährlich 2 Wochen) mit dem Ziel, für das Regelschulsystem die Projektdidaktik zu erproben und weiterzuentwickeln. Als wichtige praxisorientierte Ziele wurden ein praxistauglicher Begriff, Bildungswert und Kompetenzen im Unterschied zum Lehrgang herausgearbeitet (z.B. handlungs- und anwendungsorientierte Kompetenzen) und das Verhältnis zum Fachunterricht bestimmt (Kapitel 3). Letzteres wurde am Beispiel des Fachs Geschichte entwickelt und exemplarisch in Formen der Verzahnung dargestellt (Kapitel 6).
Auch für die methodische Dimension galt, die allgemeine Projektdidaktik weiterzuentwickeln durch ihre Abgrenzung zu anderen Methoden der Öffnung von Schule und Unterricht (Kapitel 4). Dabei wurde als zentrales methodisches Prinzip die Handlungsorientierung bestimmt sowie sieben Phasen und jeweilige Handlungsschritte festgelegt. Besonders Planung und Rollenwechsel bedürfen dabei besonderer Beachtung, um Selbsttätigkeit der ProjektteilnehmerInnen zu erreichen. Verschiedene methodische „Etüden“ ( z.B. Gruppenarbeit, recherchieren, sich öffentlich verhalten), handlungsorientierte Vorformen und projektorientiertes Arbeiten sollten die Vollform Projektunterricht vorbereiten helfen.
Die Bewertung von Projekten (Kapitel 5) stellt andere Anforderungen als der Lehrgang, weil sie unterschiedliche Bewertungsebenen (z.B. Prozessbedeutung, Produktbeurteilung, Gruppenbewertung) umfasst. Dazu sind am Oberstufen-Kolleg andere Bewertungsformen als die Ziffernnote entwickelt worden: z.B. ein „Reflexionsbericht“ als individuelle Rückmeldung von SchülerInnen und LehrerInnen und ein „Zertifikat“ für besondere Leistungen im Projekt.
Zentral für die Entwicklung von Projektunterricht ist jedoch die Organisationsfrage (Kapitel 7). Dazu bedarf es einer Organisationsgruppe Projekt, die die Unterrichtsform didaktisch betreut und in einem Hearing die angemeldeten Projekte berät. Das Oberstufen-Kolleg hat damit eine entwickelte „Projektkultur“ organisatorisch umgesetzt. Für eine empirische Untersuchung an sechs Regelschulen in Ostwestfalen ist dann eine idealtypische Merkmalsliste von schulischer „Projektkultur“ als Untersuchungsinstrument entstanden, das zugleich als Leitlinie für Schulentwicklung im Bereich Projektlernen in den Regelschulen dienen kann. Zu dieser Implementierung (Kapitel 8) wurden Konzepte und Erfahrungen vom Oberstufen-Kolleg für schulinterne und schulexterne Fortbildungsformen sowie eine exemplarische Fortbildungseinheit entwickelt. So konnten in zahlreichen Lehrerfortbildungen durch die Versuchsschule Impulse für das Regelschulsystem gegeben werden.
An important strand of research has investigated the question of how children acquire a morphological system using offline data from spontaneous or elicited child language. Most of these studies have found dissociations in how children apply regular and irregular inflection (Marcus et al. 1992, Weyerts & Clahsen 1994, Rothweiler & Clahsen 1993). These studies have considerably deepened our understanding of how linguistic knowledge is acquired and organised in the human mind. Their methodological procedures, however, do not involve measurements of how children process morphologically complex forms in real time. To date, little is known about how children process inflected word forms. The aim of this study is to investigate children’s processing of inflected words in a series of on-line reaction time experiments. We used a cross-modal priming experiment to test for decompositional effects on the central level. We used a speeded production task and a lexical decision task to test for frequency effects on access level in production and recognition. Children’s behaviour was compared to adults’ behaviour towards three participle types (-t participles, e.g. getanzt ‘danced’ vs. -n participles with stem change, e.g. gebrochen ‘broken’ vs.-n participles without stem change, e.g. geschlafen ‘slept’). For the central level, results indicate that -t participles but not -n participles have decomposed representations. For the access level, results indicate that -t participles are represented according to their morphemes and additionally as full forms, at least from the age of nine years onwards (Pinker 1999 and Clahsen et al. 2004). Further evidence suggested that -n participles are represented as full-form entries on access level and that -n participles without stem change may encode morphological structure (cf. Clahsen et al. 2003). Out data also suggests that processing strategies for -t participles are differently applied in recognition and production. These results provide evidence that children (within the age range tested) employ the same mechanisms for processing participles as adults. The child lexicon grows as children form additional full-form representations for -t participles on access level and elaborate their full-form lexical representations of -n participles on central level. These results are consistent with processing as explained in dual-system theories.
Permafrost-affected ecosystems including peat wetlands are among the most obvious regions in which current microbial controls on organic matter decomposition are likely to change as a result of global warming. Wet tundra ecosystems in particular are ideal sites for increased methane production because of the waterlogged, anoxic conditions that prevail in seasonally increasing thawed layers. The following doctoral research project focused on investigating the abundance and distribution of the methane-cycling microbial communities in four different polygons on Herschel Island and the Yukon Coast. Despite the relevance of the Canadian Western Arctic in the global methane budget, the permafrost microbial communities there have thus far remained insufficiently characterized. Through the study of methanogenic and methanotrophic microbial communities involved in the decomposition of permafrost organic matter and their potential reaction to rising environmental temperatures, the overarching goal of the ensuing thesis is to fill the current gap in understanding the fate of the organic carbon currently stored in Artic environments and its implications regarding the methane cycle in permafrost environments. To attain this goal, a multiproxy approach including community fingerprinting analysis, cloning, quantitative PCR and next generation sequencing was used to describe the bacterial and archaeal community present in the active layer of four polygons and to scrutinize the diversity and distribution of methane-cycling microorganisms at different depths. These methods were combined with soil properties analyses in order to identify the main physico-chemical variables shaping these communities. In addition a climate warming simulation experiment was carried-out on intact active layer cores retrieved from Herschel Island in order to investigate the changes in the methane-cycling communities associated with an increase in soil temperature and to help better predict future methane-fluxes from polygonal wet tundra environments in the context of climate change. Results showed that the microbial community found in the water-saturated and carbon-rich polygons on Herschel Island and the Yukon Coast was diverse and showed a similar distribution with depth in all four polygons sampled. Specifically, the methanogenic community identified resembled the communities found in other similar Arctic study sites and showed comparable potential methane production rates, whereas the methane oxidizing bacterial community differed from what has been found so far, being dominated by type-II rather than type-I methanotrophs. After being subjected to strong increases in soil temperature, the active-layer microbial community demonstrated the ability to quickly adapt and as a result shifts in community composition could be observed. These results contribute to the understanding of carbon dynamics in Arctic permafrost regions and allow an assessment of the potential impact of climate change on methane-cycling microbial communities. This thesis constitutes the first in-depth study of methane-cycling communities in the Canadian Western Arctic, striving to advance our understanding of these communities in degrading permafrost environments by establishing an important new observatory in the Circum-Arctic.
Escherichia (E.) coli ist als kommensales Bakterium ein wichtiger Bestandteil des Mikrobioms von Säugern, jedoch zudem der häufigste Infektionserreger des Menschen. Entsprechend des Infektionsortes werden intestinal (InPEC) und extraintestinal pathogene E. coli (ExPEC) unterschieden. Die Pathogenese von E. coli-Infektionen ist durch Virulenzfaktoren determiniert, welche von jeweils spezifischen virulenzassoziierten Genen (inVAGs und exVAGs) kodiert werden. Häufig werden exVAGs auch in E. coli-Isolaten aus dem Darm gesunder Wirte nachgewiesen. Dies führte zu der Vermutung, dass exVAGs die intestinale Kolonisierung des Wirtes durch E. coli unterstützen. Das Hauptziel dieser Arbeit bestand darin, das Wissen über den Einfluss von exVAGs auf die Besiedlung und damit die Adhäsion von E. coli an Epithelzellen des Darmtraktes zu erweitern. Die Durchführung einer solch umfassenden E. coli-Populationsstudie erforderte die Etablierung neuer Screeningmethoden. Für die genotypische Charakterisierung wurden mikropartikelbasierte Multiplex-PCR-Assays zum Nachweis von 44 VAGs und der Phylogenie etabliert. Für die phänotypische Charakterisierung wurden Adhäsions- und Zytotoxizitätsassays etabliert. Die Screeningmethoden basieren auf der VideoScan-Technologie, einem automatisierten bildbasierten Multifluoreszenzdetektionssystem. Es wurden 398 E. coli-Isolate aus 13 Wildsäugerarten und 5 Wildvogelarten sowie aus gesunden und harnwegserkrankten Menschen und Hausschweinen charakterisiert. Die Adhäsionsassays hatten zum Ziel, sowohl die Adhäsionsraten als auch die Adhäsionsmuster der 317 nicht hämolytischen Isolate auf 5 Epithelzelllinien zu bestimmen. Die Zytotoxizität der 81 hämolytischen Isolate wurde in Abhängigkeit der Inkubationszeit auf 4 Epithelzelllinien geprüft. In den E. coli-Isolaten wurde eine Reihe von VAGs nachgewiesen. Potentielle InPEC, insbesondere shigatoxinproduzierende und enteropathogene E. coli wurden aus Menschen, Hausschweinen und Wildtieren, vor allem aus Rehen und Feldhasen isoliert. exVAGs wurden mit stark variierender Prävalenz in Isolaten aus allen Arten detektiert. Die größte Anzahl und das breiteste Spektrum an exVAGs wurde in Isolaten aus Urin harnwegserkrankter Menschen, gefolgt von Isolaten aus Dachsen und Rehen nachgewiesen. In Isolaten der phylogenetischen Gruppe B2 wurden mehr exVAGs detektiert als in den Isolaten der phylogenetischen Gruppen A, B1 und D. Die Ergebnisse der Adhäsionsassays zeigten, dass die meisten Isolate zelllinien-, gewebe- oder wirtsspezifisch adhärierten. Ein Drittel der Isolate adhärierte an keiner Zelllinie und nur zwei Isolate adhärierten stark an allen Zelllinien. Grundsätzlich adhärierten mehr Isolate an humanen sowie an intestinalen Zelllinien. Besonders Isolate aus Eichhörnchen und Amseln sowie aus Urin harnwegserkrankter Menschen und Hausschweine waren in der Lage, stark zu adhärieren. Hierbei bildeten die Isolate als Adhäsionsmuster diffuse Adhäsion, Mikrokolonien, Ketten und Agglomerationen. Mittels statistischer Analysen wurden Assoziationen zwischen exVAGs und einer hohen Adhäsionsrate ersichtlich. So war beispielsweise das Vorkommen von afa/dra mit einer höheren Adhäsionsrate auf Caco-2- und 5637-Zellen und von sfa/foc auf IPEC-J2-Zellen assoziiert. Die Ergebnisse der Zytotoxizitätsassays zeigten eine sehr starke und zeitabhängige Zerstörung der Monolayer aller Epithelzelllinien durch die α-Hämolysin-positiven Isolate. Auffallend war die hohe Toxizität hämolytischer Isolate aus Wildtieren gegenüber den humanen Zelllinien. Mit den innerhalb dieser Arbeit entwickelten Screeningmethoden war es möglich, große Mengen an Bakterien zu charakterisieren. Es konnte ein Überblick über die Verbreitung von VAGs in E. coli aus unterschiedlichen Wirten gewonnen werden. Besonders Wildtiere wurden sowohl durch den Nachweis von VAGs in den entsprechenden Isolaten, verbunden mit deren Adhäsionsfähigkeit und ausgeprägter Zytotoxizität als Reservoire pathogener E. coli identifiziert. Ebenso wurde eine zelllinienspezifische Adhäsion von Isolaten mit bestimmten exVAGs deutlich. Damit konnte der mögliche Einfluss von exVAGs auf die intestinale Kolonisierung bestätigt werden. In weiterführenden Arbeiten sind jedoch Expressions- und Funktionsanalysen der entsprechenden Proteine unerlässlich. Es wird anhand der Mikrokoloniebildung durch kommensale E. coli vermutet, dass Adhäsionsmuster und demzufolge Kolonisierungsstrategien, die bisher pathogenen E. coli zugeschrieben wurden, eher als generelle Kolonisierungsstrategien zu betrachten sind. Das E. coli-α-Hämolysin wirkt im Allgemeinen zytotoxisch auf Epithelzellen. Ein in der Fachliteratur diskutierter adhäsionsunterstützender Mechanismus dieses Toxins ist demnach fragwürdig. Innerhalb dieser Arbeit konnte gezeigt werden, dass die entwickelten Screeningmethoden umfassende Analysen einer großen Anzahl an E. coli-Isolaten ermöglichen.
In sedimentary basins, rock thermal conductivity can vary both laterally and vertically, thus altering the basin’s thermal structure locally and regionally. Knowledge of the thermal conductivity of geological formations and its spatial variations is essential, not only for quantifying basin evolution and hydrocarbon maturation processes, but also for understanding geothermal conditions in a geological setting. In conjunction with the temperature gradient, thermal conductivity represents the basic input parameter for the determination of the heat-flow density; which, in turn, is applied as a major input parameter in thermal modeling at different scales. Drill-core samples, which are necessary to determine thermal properties by laboratory measurements, are rarely available and often limited to previously explored reservoir formations. Thus, thermal conductivities of Mesozoic rocks in the North German Basin (NGB) are largely unknown. In contrast, geophysical borehole measurements are often available for the entire drilled sequence. Therefore, prediction equations to determine thermal conductivity based on well-log data are desirable. In this study rock thermal conductivity was investigated on different scales by (1) providing thermal-conductivity measurements on Mesozoic rocks, (2) evaluating and improving commonly applied mixing models which were used to estimate matrix and pore-filled rock thermal conductivities, and (3) developing new well-log based equations to predict thermal conductivity in boreholes without core control. Laboratory measurements are performed on sedimentary rock of major geothermal reservoirs in the Northeast German Basin (NEGB) (Aalenian, Rhaethian-Liassic, Stuttgart Fm., and Middle Buntsandstein). Samples are obtained from eight deep geothermal wells that approach depths of up to 2,500 m. Bulk thermal conductivities of Mesozoic sandstones range between 2.1 and 3.9 W/(m∙K), while matrix thermal conductivity ranges between 3.4 and 7.4 W/(m∙K). Local heat flow for the Stralsund location averages 76 mW/m², which is in good agreement to values reported previously for the NEGB. For the first time, in-situ bulk thermal conductivity is indirectly calculated for entire borehole profiles in the NEGB using the determined surface heat flow and measured temperature data. Average bulk thermal conductivity, derived for geological formations within the Mesozoic section, ranges between 1.5 and 3.1 W/(m∙K). The measurement of both dry- and water-saturated thermal conductivities allow further evaluation of different two-component mixing models which are often applied in geothermal calculations (e.g., arithmetic mean, geometric mean, harmonic mean, Hashin-Shtrikman mean, and effective-medium theory mean). It is found that the geometric-mean model shows the best correlation between calculated and measured bulk thermal conductivity. However, by applying new model-dependent correction, equations the quality of fit could be significantly improved and the error diffusion of each model reduced. The ‘corrected’ geometric mean provides the most satisfying results and constitutes a universally applicable model for sedimentary rocks. Furthermore, lithotype-specific and model-independent conversion equations are developed permitting a calculation of water-saturated thermal conductivity from dry-measured thermal conductivity and porosity within an error range of 5 to 10%. The limited availability of core samples and the expensive core-based laboratory measurements make it worthwhile to use petrophysical well logs to determine thermal conductivity for sedimentary rocks. The approach followed in this study is based on the detailed analyses of the relationships between thermal conductivity of rock-forming minerals, which are most abundant in sedimentary rocks, and the properties measured by standard logging tools. By using multivariate statistics separately for clastic, carbonate and evaporite rocks, the findings from these analyses allow the development of prediction equations from large artificial data sets that predict matrix thermal conductivity within an error of 4 to 11%. These equations are validated successfully on a comprehensive subsurface data set from the NGB. In comparison to the application of earlier published approaches formation-dependent developed for certain areas, the new developed equations show a significant error reduction of up to 50%. These results are used to infer rock thermal conductivity for entire borehole profiles. By inversion of corrected in-situ thermal-conductivity profiles, temperature profiles are calculated and compared to measured high-precision temperature logs. The resulting uncertainty in temperature prediction averages < 5%, which reveals the excellent temperature prediction capabilities using the presented approach. In conclusion, data and methods are provided to achieve a much more detailed parameterization of thermal models.
African states are often called corrupt indicating that the political system in Africa differs from the one prevalent in the economically advanced democracies. This however does not give us any insight into what makes corruption the ruling norm of African statehood. Thus we must turn to the overly neglected theoretical work on the political economy of Africa in order to determine how the poverty of governance in Africa is firmly anchored both in Africa’s domestic socioeconomic reality, as well as in the region’s role in the international economic order. Instead of focusing on increased monitoring, enforcement and formal democratic procedures, this book integrates economic analysis with political theory in order to arrive at a better understanding of the political-economic roots of corruption in Sub-Saharan Africa.
Initiation and perpetuation of inflammatory bowel diseases (IBD) may result from an exaggerated mucosal immune response to the luminal microbiota in a susceptible host. We proposed that this may be caused either 1) by an abnormal microbial composition or 2) by weakening of the protective mucus layer due to excessive mucus degradation, which may lead to an easy access of luminal antigens to the host mucosa triggering inflammation. We tested whether the probiotic Enterococcus faecium NCIMB 10415 (NCIMB) is capable of reducing chronic gut inflammation by changing the existing gut microbiota composition and aimed to identify mechanisms that are involved in possible beneficial effects of the probiotic. To identify health-promoting mechanisms of the strain, we used interleukin (IL)-10 deficient mice that spontaneously develop gut inflammation and fed these mice a diet containing NCIMB (106 cells g-1) for 3, 8 and 24 weeks, respectively. Control mice were fed an identically composed diet but without the probiotic strain. No clear-cut differences between the animals were observed in pro-inflammatory cytokine gene expression and in intestinal microbiota composition after probiotic supplementation. However, we observed a low abundance of the mucin-degrading bacterium Akkermansia muciniphila in the mice that were fed NCIMB for 8 weeks. These low cell numbers were associated with significantly lower interferon gamma (IFN-γ) and IFN-γ-inducible protein (IP-10) mRNA levels as compared to the NCIMB-treated mice that were killed after 3 and 24 weeks of intervention. In conclusion, NCIMB was not capable of reducing gut inflammation in the IL-10-/- mouse model. To further identify the exact role of A. muciniphila and uncover a possible interaction between this bacterium, NCIMB and the host in relation to inflammation, we performed in vitro studies using HT-29 colon cancer cells. The HT-29 cells were treated with bacterial conditioned media obtained by growing either A. muciniphila (AM-CM) or NCIMB (NCIMB-CM) or both together (COMB-CM) in Dulbecco’s Modified Eagle Medium (DMEM) for 2 h at 37 °C followed by bacterial cell removal. HT-29 cells treated with COMB-CM displayed reduced cell viability after 18 h (p<0.01) and no viable cells were detected after 24 h of treatment, in contrast to the other groups or heated COMB-CM. Detection of activated caspase-3 in COMB-CM treated groups indicated that death of the HT-29 cells was brought about by apoptosis. It was concluded that either NCIMB or A. muciniphila produce a soluble and heat-sensitive factor during their concomitant presence that influences cell viability in an in vitro system. We currently hypothesize that this factor is a protein, which has not yet been identified. Based on the potential effect of A. muciniphila on inflammation (in vivo) and cell-viability (in vitro) in the presence of NCIMB, we investigated how the presence of A. muciniphila affects the severity of an intestinal Salmonella enterica Typhimurium (STm)-induced gut inflammation using gnotobiotic C3H mice with a background microbiota of eight bacterial species (SIHUMI, referred to as simplified human intestinal microbiota). Presence of A. muciniphila in STm-infected SIHUMI (SIHUMI-AS) mice caused significantly increased histopathology scores and elevated mRNA levels of IFN-γ, IP-10, tumor necrosis factor alpha (TNF-α), IL-12, IL-17 and IL-6 in cecal and colonic tissue. The number of mucin filled goblet cells was 2- to 3- fold lower in cecal tissue of SIHUMI-AS mice compared to SIHUMI mice associated with STm (SIHUMI-S) or A. muciniphila (SIHUMI-A) or SIHUMI mice. Reduced goblet cell numbers significantly correlated with increased IFN-γ (r2 = -0.86, ***P<0.001) in all infected mice. In addition, loss of cecal mucin sulphation was observed in SIHUMI-AS mice. Concomitant presence of A. muciniphila and STm resulted in a drastic change in microbiota composition of the SIHUMI consortium. The proportion of Bacteroides thetaiotaomicron in SIHUMI, SIHUMI-A and SIHUMI-S mice made up to 80-90% but was completely taken over by STm in SIHUMI-AS mice contributing 94% to total bacteria. These results suggest that A. muciniphila exacerbates STm-induced intestinal inflammation by its ability to disturb host mucus homeostasis. In conclusion, abnormal microbiota composition together with excessive mucus degradation contributes to severe intestinal inflammation in a susceptible host.
Interactive generation of effective discourse in situated context : a planning-based approach
(2013)
As our modern-built structures are becoming increasingly complex, carrying out basic tasks such as identifying points or objects of interest in our surroundings can consume considerable time and cognitive resources. In this thesis, we present a computational approach to converting contextual information about a person's physical environment into natural language, with the aim of helping this person identify given task-related entities in their environment. Using efficient methods from automated planning - the field of artificial intelligence concerned with finding courses of action that can achieve a goal -, we generate discourse that interactively guides a hearer through completing their task. Our approach addresses the challenges of controlling, adapting to, and monitoring the situated context. To this end, we develop a natural language generation system that plans how to manipulate the non-linguistic context of a scene in order to make it more favorable for references to task-related objects. This strategy distributes a hearer's cognitive load of interpreting a reference over multiple utterances rather than one long referring expression. Further, to optimize the system's linguistic choices in a given context, we learn how to distinguish speaker behavior according to its helpfulness to hearers in a certain situation, and we model the behavior of human speakers that has been proven helpful. The resulting system combines symbolic with statistical reasoning, and tackles the problem of making non-trivial referential choices in rich context. Finally, we complement our approach with a mechanism for preventing potential misunderstandings after a reference has been generated. Employing remote eye-tracking technology, we monitor the hearer's gaze and find that it provides a reliable index of online referential understanding, even in dynamically changing scenes. We thus present a system that exploits hearer gaze to generate rapid feedback on a per-utterance basis, further enhancing its effectiveness. Though we evaluate our approach in virtual environments, the efficiency of our planning-based model suggests that this work could be a step towards effective conversational human-computer interaction situated in the real world.
Unter geeigneten Wachstumsbedingungen weisen Algenkulturen oft eine größere Produktivität der Zellen auf, als sie bei höheren Pflanzen zu beobachten ist. Chlamydomonas reinhardtii-Zellen sind vergleichsweise klein. So beträgt das Zellvolumen während des vegetativen Zellzyklus etwa 50–3500 µm³. Im Vergleich zu höheren Pflanzen ist in einer Algensuspension die Konzentration der Biomasse allerdings gering. So enthält beispielsweise 1 ml einer üblichen Konzentration zwischen 10E6 und 10E7 Algenzellen. Quantifizierungen von Metaboliten oder Makromolekülen, die zur Modellierung von zellulären Prozessen genutzt werden, werden meist im Zellensemble vorgenommen. Tatsächlich unterliegt jedoch jede Algenzelle einer individuellen Entwicklung, die die Identifizierung charakteristischer allgemeingültiger Systemparameter erschwert. Ziel dieser Arbeit war es, biochemisch relevante Messgrößen in-vivo und in-vitro mit Hilfe optischer Verfahren zu identifizieren und zu quantifizieren. Im ersten Teil der Arbeit wurde ein Puls-Amplituden-Modulation(PAM)-Fluorimetriemessplatz zur Messung der durch äußere Einflüsse bedingten veränderlichen Chlorophyllfluoreszenz an einzelnen Zellen vorgestellt. Die Verwendung eines kommerziellen Mikroskops, die Implementierung empfindlicher Nachweiselektronik und einer geeignete Immobilisierungsmethode ermöglichten es, ein Signal-zu-Rauschverhältnis zu erreichen, mit dem Fluoreszenzsignale einzelner lebender Chlamydomonas-Zellen gemessen werden konnten. Insbesondere wurden das Zellvolumen und der als Maß für die Effizienz des Photosyntheseapparats bzw. die Zellfitness geltende Chlorophyllfluoreszenzparameter Fv/Fm ermittelt und ein hohes Maß an Heterogenität dieser zellulären Parameter in verschiedenen Entwicklungsstadien der synchronisierten Chlamydomonas-Zellen festgestellt. Im zweiten Teil der Arbeit wurden die bildgebende Laser-Scanning-Mikroskopie und anschließende Bilddatenanalyse zur quantitativen Erfassung der wachstumsabhängigen zellulären Parameter angewandt. Ein kommerzielles konfokales Mikroskop wurde um die Möglichkeit der nichtlinearen Mikroskopie erweitert. Diese hat den Vorteil einer lokalisierten Anregung, damit verbunden einer höheren Ortsauflösung und insgesamt geringeren Probenbelastung. Weiterhin besteht neben der Signalgewinnung durch Fluoreszenzanregung die Möglichkeit der Erzeugung der Zweiten Harmonischen (SHG) an biophotonischen Strukturen, wie der zellulären Stärke. Anhand der Verteilungsfunktionen war es möglich mit Hilfe von modelltheoretischen Ansätzen zelluläre Parameter zu ermitteln, die messtechnisch nicht unmittelbar zugänglich sind. Die morphologischen Informationen der Bilddaten ermöglichten die Bestimmung der Zellvolumina und die Volumina subzellularer Strukturen, wie Nuclei, extranucleäre DNA oder Stärkegranula. Weiterhin konnte die Anzahl subzellulärer Strukturen innerhalb einer Zelle bzw. eines Zellverbunds ermittelt werden. Die Analyse der in den Bilddaten enthaltenen Signalintensitäten war Grundlage einer relativen Konzentrationsbestimmung von zellulären Komponenten, wie DNA bzw. Stärke. Mit dem hier vorgestellten Verfahren der nichtlinearen Mikroskopie und nachfolgender Bilddatenanalyse konnte erstmalig die Verteilung des zellulären Stärkegehalts in einer Chlamydomonas-Population während des Wachstums bzw. nach induziertem Stärkeabbau verfolgt werden. Im weiteren Verlauf wurde diese Methode auch auf Gefrierschnitte höherer Pflanzen, wie Arabidopsis thaliana, angewendet. Im Ergebnis wurde gezeigt, dass viele zelluläre Parameter, wie das Volumen, der zelluläre DNA- und Stärkegehalt bzw. die Anzahl der Stärkegranula durch eine Lognormalverteilung, mit wachstumsabhängiger Parametrisierung, beschrieben werden. Zelluläre Parameter, wie Stoffkonzentration und zelluläres Volumen, zeigen keine signifikanten Korrelationen zueinander, woraus geschlussfolgert werden muss, dass es ein hohes Maß an Heterogenität der zellulären Parameter innerhalb der synchronisierten Chlamydomonas-Populationen gibt. Diese Aussage gilt sowohl für die als homogenste Form geltenden Synchronkulturen von Chlamydomonas reinhardtii als auch für die gemessenen zellulären Parameter im intakten Zellverbund höherer Pflanzen. Dieses Ergebnis ist insbesondere für modelltheoretische Betrachtungen von Relevanz, die sich auf empirische Daten bzw. zelluläre Parameter stützen welche im Zellensemble gemessen wurden und somit nicht notwendigerweise den zellulären Status einer einzelnen Zelle repräsentieren.
This dissertation is about factors that contribute to the surface forms of tones in connected speech in Akan. Akan is an African tone language, which is spoken in Ghana. It has two level tones (low and high), automatic and non-automatic downstep. Downstep is the major factor that influences the surface forms of tones. The thesis shows that downstep is caused by declination. It is argued that declination is an intonational property of Akan, which serves to signal coherence. A phonological representation using a high and a low register tone, associating to the left and right edge of an intonational phrase (IP), respectively, is proposed. Declination/downstep is modelled using a (phonetic) pitch implementation algorithm (Liberman & Pierrehumbert, 1984). An innovative application of the algorithm is presented, which naturally captures the relation between declination and downstep in Akan. Another important factor is the prosodic manifestation of sentence level pragmatic meanings, such as sentence mode and focus. Regarding the former, the thesis shows that a post-lexical low tone, which associates with the right edge of an IP, signals interrogativity. Additionally, lexical tones in Yes – No questions are realized in a higher pitch register, which does not lead to a reduction of declination. It is claimed that the higher register is not part of the phonological representation in Akan, but that it emerges at the phonetic level to compensate for the ‘unnatural’ form of the question morpheme and to satisfy the Frequency code (Gussenhoven, 2002; 2004). An extension of Rialland’s (2007) typology in terms of a new category called “low tense” question prosody is proposed. Concerning focus marking, it is argued that the use of the morpho-syntactic focus marking strategy is related to extra grammatical factors, such as hearer expectation, discourse expectability (Zimmermann, 2007) and emphasis (Hartmann, 2008). If a speaker of Akan wants to highlight a particular element in a sentence, in-situ, i.e. by means of prosody, the default prosodic structure is modified in such a way that the focused element forms its own phonological phrase (pP). If it is already contained in a pP, the boundary deliminating the focused element is enhanced (Féry, 2012). This restructuring/enhancement is accompanied by an interruption of the otherwise continuous melody due to insertion of a pause and/or a glottal stop. Beside declination and intonation, raising of H tones applies in Akan. H raising is analyzed as a local anticipatory planning effect, employed at the phonetic level, which enhances the perceptual distance between low and high tones. Low tones are raised, if they are wedged between two high tones. L raising is argued to be a local carryover effect (co-articulation). Further, it is demonstrated that global anticipatory raising takes place. It is shown that Akan speakers anticipate the length of an IP. Preplanning (anticipatory raising) is argued to be an important process at the level of pitch implementation. It serves to ensure that declination can be maintained throughout the IP, which prevents pitch resetting.
The melody of an Akan sentence is largely determined by the choice of words. The inventory of post-lexical tones is small. It consists of post-lexical register tones, which trigger declination and post-lexical intonational tones, which signal sentence type. The overall melodic shape is falling. At the local level, H raising and L raising occur. At the global level, initial low and high tones are realized higher if they occur in a long and/or complex sentence. This dissertation shows that many factors, which emerge at different levels of the tone production process, contribute to the surface form of tones in Akan.
Cellulose is the most abundant biopolymer on earth. In this work it has been used, in various forms ranging from wood to fully processed laboratory grade microcrystalline cellulose, to synthesise a variety of metal and metal carbide nanoparticles and to establish structuring and patterning methodologies that produce highly functional nano-hybrids. To achieve this, the mechanisms governing the catalytic processes that bring about graphitised carbons in the presence of iron have been investigated. It was found that, when infusing cellulose with an aqueous iron salt solution and heating this mixture under inert atmosphere to 640 °C and above, a liquid eutectic mixture of iron and carbon with an atom ratio of approximately 1:1 forms. The eutectic droplets were monitored with in-situ TEM at the reaction temperature where they could be seen dissolving amorphous carbon and leaving behind a trail of graphitised carbon sheets and subsequently iron carbide nanoparticles. These transformations turned ordinary cellulose into a conductive and porous matrix that is well suited for catalytic applications. Despite these significant changes on the nanometre scale the shape of the matrix as a whole was retained with remarkable precision. This was exemplified by folding a sheet of cellulose paper into origami cranes and converting them via the temperature treatment in to magnetic facsimiles of those cranes. The study showed that the catalytic mechanisms derived from controlled systems and described in the literature can be transferred to synthetic concepts beyond the lab without loss of generality. Once the processes determining the transformation of cellulose into functional materials were understood, the concept could be extended to other metals and metal-combinations. Firstly, the procedure was utilised to produce different ternary iron carbides in the form of MxFeyC (M = W, Mn). None of those ternary carbides have thus far been produced in a nanoparticle form. The next part of this work encompassed combinations of iron with cobalt, nickel, palladium and copper. All of those metals were also probed alone in combination with cellulose. This produced elemental metal and metal alloy particles of low polydispersity and high stability. Both features are something that is typically not associated with high temperature syntheses and enables to connect the good size control with a scalable process. Each of the probed reactions resulted in phase pure, single crystalline, stable materials. After showing that cellulose is a good stabilising and separating agent for all the investigated types of nanoparticles, the focus of the work at hand is shifted towards probing the limits of the structuring and pattering capabilities of cellulose. Moreover possible post-processing techniques to further broaden the applicability of the materials are evaluated. This showed that, by choosing an appropriate paper, products ranging from stiff, self-sustaining monoliths to ultra-thin and very flexible cloths can be obtained after high temperature treatment. Furthermore cellulose has been demonstrated to be a very good substrate for many structuring and patterning techniques from origami folding to ink-jet printing. The thereby resulting products have been employed as electrodes, which was exemplified by electrodepositing copper onto them. Via ink-jet printing they have additionally been patterned and the resulting electrodes have also been post functionalised by electro-deposition of copper onto the graphitised (printed) parts of the samples. Lastly in a preliminary test the possibility of printing several metals simultaneously and thereby producing finely tuneable gradients from one metal to another have successfully been made. Starting from these concepts future experiments were outlined. The last chapter of this thesis concerned itself with alternative synthesis methods of the iron-carbon composite, thereby testing the robustness of the devolved reactions. By performing the synthesis with partly dissolved scrap metal and pieces of raw, dry wood, some progress for further use of the general synthesis technique were made. For example by using wood instead of processed cellulose all the established shaping techniques available for wooden objects, such as CNC milling or 3D prototyping, become accessible for the synthesis path. Also by using wood its intrinsic well defined porosity and the fact that large monoliths are obtained help expanding the prospect of using the composite. It was also demonstrated in this chapter that the resulting material can be applied for the environmentally important issue of waste water cleansing. Additionally to being made from renewable resources and by a cheap and easy one-pot synthesis, the material is recyclable, since the pollutants can be recovered by washing with ethanol. Most importantly this chapter covered experiments where the reaction was performed in a crude, home-built glass vessel, fuelled – with the help of a Fresnel lens – only by direct concentrated sunlight irradiation. This concept carries the thus far presented synthetic procedures from being common laboratory syntheses to a real world application. Based on cellulose, transition metals and simple equipment, this work enabled the easy one-pot synthesis of nano-ceramic and metal nanoparticle composites otherwise not readily accessible. Furthermore were structuring and patterning techniques and synthesis routes involving only renewable resources and environmentally benign procedures established here. Thereby it has laid the foundation for a multitude of applications and pointed towards several future projects reaching from fundamental research, to application focussed research and even and industry relevant engineering project was envisioned.
One of the central questions in psycholinguistic is understanding whether and how prosodic phrase boundaries are used to resolve syntactic ambiguities in sentence processing. The present work aimed to answer both, first, the effects of φ- and ι-boundaries on syntactic ambiguity resolution, and second, how the prosodic correlates of the auditory input are taken for the phonetic-phonology mapping in order to attain a meaningful sentence interpretation.
With regard to the first aim, we investigated locally syntactic ambiguities involving either φ- or ι-phrase boundaries in German and the structural preference that listeners have, based on the prosodic content. The experiments described in this work show that German listeners exploit both types of prosodic phrase boundaries to resolve local syntactic ambiguities, that however, their disambiguation altered by the presence or absence of prosodic cues correlated with the corresponding boundary. Specifically, the perception data revealed that the phonetically measured prosodic correlates of each prosodic boundary such as pitch accents, boundary tones, deaccentuation and durational properties do not contribute to ambiguity resolution in equal measure. Rather, it is the case that listeners rely primarily on prefinal lengthening as a correlate of phrasing in the vicinity of φ-phrase boundaries, while at the level of the ι-phrase boundary, boundary tones serve as phrasal cues. This way the results of the present work take account of the as yet missing information on individual contributions of prosodic correlates on listeners’ disambiguation of syntactically ambiguous sentences in German. It further implies that the question of how German listeners resolve syntactic ambiguities cannot simply be attributed to the presence or absence of prosodic correlates. The interpretation of the phrasal structure rather depends on a more general picture of cohesion between prosodic correlates and prosodic boundary sizes.
With respect to the second aim, the processing models proposed in the present work describe a specific phonetics-phonology mapping in the vicinity of both phrase boundaries. It is assumed that auditory sentence processing proceeds in several successively organized steps, during which listeners transform overt phonetic forms into language specific abstract surface forms. This process is referred to as phonetics-phonology mapping in the present work. Perceptual evidence resulting from the experiments of the present work suggest that the phonetics-phonology mapping is guided by the above mentioned boundary related prosodic correlates. The resulting abstract phonological structure is subjected to the syntax-prosody mapping, in turn. The outcome of the presented perception experiments are modulated in an Optimality-Theoretic framework. The offered OT-models are grounded on the assumption that single prosodic correlates are used by listeners as a signal to syntax in sentence processing. This is in line with studies arguing that the prosodic phrase structure determines the syntactic parse (Cutler et al., 1997; Warren et al., 1995; Pynte & Prieur, 1996; Snedeker & Trueswell, 2003; Kjelgaard & Speer, 1999), to name just a few.
Passive plant actuators have fascinated many researchers in the field of botany and structural biology since at least one century. Up to date, the most investigated tissue types in plant and artificial passive actuators are fibre-reinforced composites (and multilayered assemblies thereof) where stiff, almost inextensible cellulose microfibrils direct the otherwise isotropic swelling of a matrix. In addition, Nature provides examples of actuating systems based on lignified, low-swelling, cellular solids enclosing a high-swelling cellulosic phase. This is the case of the Delosperma nakurense seed capsule, in which a specialized tissue promotes the reversible opening of the capsule upon wetting. This tissue has a diamond-shaped honeycomb microstructure characterized by high geometrical anisotropy: when the cellulosic phase swells inside this constraining structure, the tissue deforms up to four times in one principal direction while maintaining its original dimension in the other. Inspired by the example of the Delosoperma nakurense, in this thesis we analyze the role of architecture of 2D cellular solids as models for natural hygromorphs. To start off, we consider a simple fluid pressure acting in the cells and try to assess the influence of several architectural parameters onto their mechanical actuation. Since internal pressurization is a configurational type of load (that is the load direction is not fixed but it “follows” the structure as it deforms) it will result in the cellular structure acquiring a “spontaneous” shape. This shape is independent of the load but just depends on the architectural characteristics of the cells making up the structure itself. Whereas regular convex tiled cellular solids (such as hexagonal, triangular or square lattices) deform isotropically upon pressurization, we show through finite element simulations that by introducing anisotropic and non-convex, reentrant tiling large expansions can be achieved in each individual cell. The influence of geometrical anisotropy onto the expansion behaviour of a diamond shaped honeycomb is assessed by FEM calculations and a Born lattice approximation. We found that anisotropic expansions (eigenstrains) comparable to those observed in the keels tissue of the Delosoperma nakurense are possible. In particular these depend on the relative contributions of bending and stretching of the beams building up the honeycomb. Moreover, by varying the walls’ Young modulus E and internal pressure p we found that both the eigenstrains and 2D elastic moduli scale with the ratio p/E. Therefore the potential of these pressurized structures as soft actuators is outlined. This approach was extended by considering several 2D cellular solids based on two types of non-convex cells. Each honeycomb is build as a lattice made of only one non-convex cell. Compared to usual honeycombs, these lattices have kinked walls between neighbouring cells which offers a hidden length scale allowing large directed deformations. By comparing the area expansion in all lattices, we were able to show that less convex cells are prone to achieve larger area expansions, but the direction in which the material expands is variable and depends on the local cell’s connectivity. This has repercussions both at the macroscopic (lattice level) and microscopic (cells level) scales. At the macroscopic scale, these non-convex lattices can experience large anisotropic (similarly to the diamond shaped honeycomb) or perfectly isotropic principal expansions, large shearing deformations or a mixed behaviour. Moreover, lattices that at the macroscopic scale expand similarly can show quite different microscopic deformation patterns that include zig-zag motions and radical changes of the initial cell shape. Depending on the lattice architecture, the microscopic deformations of the individual cells can be equal or not, so that they can build up or mutually compensate and hence give rise to the aforementioned variety of macroscopic behaviours. Interestingly, simple geometrical arguments involving the undeformed cell shape and its local connectivity enable to predict the results of the FE simulations. Motivated by the results of the simulations, we also created experimental 3D printed models of such actuating structures. When swollen, the models undergo substantial deformation with deformation patterns qualitatively following those predicted by the simulations. This work highlights how the internal architecture of a swellable cellular solid can lead to complex shape changes which may be useful in the fields of soft robotics or morphing structures.
User-centered design processes are the first choice when new interactive systems or services are developed to address real customer needs and provide a good user experience. Common tools for collecting user research data, conducting brainstormings, or sketching ideas are whiteboards and sticky notes. They are ubiquitously available, and no technical or domain knowledge is necessary to use them. However, traditional pen and paper tools fall short when saving the content and sharing it with others unable to be in the same location. They are also missing further digital advantages such as searching or sorting content. Although research on digital whiteboard and sticky note applications has been conducted for over 20 years, these tools are not widely adopted in company contexts. While many research prototypes exist, they have not been used for an extended period of time in a real-world context. The goal of this thesis is to investigate what the enablers and obstacles for the adoption of digital whiteboard systems are. As an instrument for different studies, we developed the Tele-Board software system for collaborative creative work. Based on interviews, observations, and findings from former research, we tried to transfer the analog way of working to the digital world. Being a software system, Tele-Board can be used with a variety of hardware and does not depend on special devices. This feature became one of the main factors for adoption on a larger scale. In this thesis, I will present three studies on the use of Tele-Board with different user groups and foci. I will use a combination of research methods (laboratory case studies and data from field research) with the overall goal of finding out when a digital whiteboard system is used and in which cases not. Not surprisingly, the system is used and accepted if a user sees a main benefit that neither analog tools nor other applications can offer. However, I found that these perceived benefits are very different for each user and usage context. If a tool provides possibilities to use in different ways and with different equipment, the chances of its adoption by a larger group increase. Tele-Board has now been in use for over 1.5 years in a global IT company in at least five countries with a constantly growing user base. Its use, advantages, and disadvantages will be described based on 42 interviews and usage statistics from server logs. Through these insights and findings from laboratory case studies, I will present a detailed analysis of digital whiteboard use in different contexts with design implications for future systems.