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Dieser Beitrag stellt das Lehr-Lern-Konzept zur Kompetenzförderung im Software Engineering im Studiengang Mechatronik der Hochschule Aschaffenburg dar. Dieses Konzept ist mehrstufig mit Vorlesungs-, Seminar- und Projektsequenzen. Dabei werden Herausforderungen und Verbesserungspotentiale identifiziert und dargestellt. Abschließend wird ein Überblick gegeben, wie im Rahmen eines gerade gestarteten Forschungsprojektes Lehr-Lernkonzepte weiterentwickelt werden können.
Der traditionelle Weg in der Informatik besteht darin, Kompetenzen entweder normativ durch eine Expertengruppe festzulegen oder als Ableitungsergebnis eines Bildungsstandards aus einem externen Feld. Dieser Artikel stellt einen neuartigen und alternativen Ansatz vor, der sich der Methodik der Qualitativen Inhaltsanalyse (QI) bedient. Das Ziel war die Ableitung von informatischen Schlüsselkompetenzen anhand bereits etablierter und erprobter didaktischer Ansätze der Informatikdidaktik. Dazu wurde zunächst aus einer Reihe von Informatikdidaktikbüchern eine Liste mit möglichen Kandidaten für Kompetenzen generiert. Diese Liste wurde als QI-Kategoriensystem verwendet, mit der sechs verschiedene didaktische Ansätze analysiert wurden. Ein abschließender Verfeinerungsschritt erfolgte durch die Überprüfung, welche der gefundenen Kompetenzen in allen vier Kernbereichen der Informatik (theoretische, technische, praktische und angewandte Informatik) Anwendung finden. Diese Methode wurde für die informatische Schulausbildung exemplarisch entwickelt und umgesetzt, ist aber ebenfalls ein geeignetes Vorgehen für die Identifizierung von Schlüsselkompetenzen in anderen Gebieten, wie z. B. in der informatischen Hochschulausbildung, und soll deshalb hier kurz vorgestellt werden.
Informatik im Alltag
(2013)
Die Fachwissenschaft Informatik stellt Mittel bereit, deren Nutzung für Studierende heutzutage selbstverständlich ist. Diese Tatsache darf uns allerdings nicht dar- über hinwegtäuschen, dass Studierende in der Regel keine Grundlage im Sinne einer informatischen Allgemeinbildung gemäÿ der Bildungsstandards der Gesellschaft für Informatik besitzen. Das Schulfach Informatik hat immer noch keinen durchgängigen Platz in den Stundentafeln der allgemein bildenden Schule gefunden. Zukünftigen Lehrkräften ist im Rahmen der bildungswissenschaftlichen Anteile im Studium eine hinreichende Medienkompetenz zu vermitteln. Mit der überragenden Bedeutung der digitalen Medien kann dies nur auf der Grundlage einer ausreichenden informatischen Grundbildung erfolgen. Damit ist es angezeigt, ein Studienangebot bereitzustellen, das allen Studierenden ein Eintauchen in Elemente (Fachgebiete) der Fachwissenschaft Informatik aus der Sicht des Alltags bietet. An diesen Elementen werden exemplarisch verschiedene Aspekte der Fachwissenschaft beleuchtet, um einen Einblick in die Vielgestaltigkeit der Fragen und Lösungsstrategien der Informatik zu erlauben und so die informatische Grundbildung zu befördern.
The aim of our article is to collect and present information about contemporary programming environments that are suitable for primary education. We studied the ways they implement (or do not implement) some programming concepts, the ways programs are represented and built in order to support young and novice programmers, as well as their suitability to allow different forms of sharing the results of pupils’ work. We present not only a short description of each considered environment and the taxonomy in the form of a table, but also our understanding and opinions on how and why the environments implement the same concepts and ideas in different ways and which concepts and ideas seem to be important to the creators of such environments.
A comparison of current trends within computer science teaching in school in Germany and the UK
(2013)
In the last two years, CS as a school subject has gained a lot of attention worldwide, although different countries have differing approaches to and experiences of introducing CS in schools. This paper reports on a study comparing current trends in CS at school, with a major focus on two countries, Germany and UK. A survey was carried out of a number of teaching professionals and experts from the UK and Germany with regard to the content and delivery of CS in school. An analysis of the quantitative data reveals a difference in foci in the two countries; putting this into the context of curricular developments we are able to offer interpretations of these trends and suggest ways in which curricula in CS at school should be moving forward.
This article is a summary of the work carried out by the Ministry of Education in Turkey, in terms of the development of a new ICT Curriculum, together with the e-Training of teachers who will play an important role in the forthcoming pilot study. Based on recent literature on the topic, the article starts by introducing the “F@tih Project”, a national project that aims to effectively integrate technology into schools. After assessing teachers’ and students’ ICT competencies, as defined internationally, the review continues with the proposed model for the e-training of teachers. Summarizing the process of development of the new ICT curriculum, researchers underline key points of the curriculum such as dimensions, levels and competencies. Then teachers’ e-training approaches, together with selected tools, are explained in line with the importance and stages of action research that will be used throughout the pilot implementation of the curriculum and e-training process.
Japan launched the new Course of Study in April 2012, which has been carried out in elementary schools and junior high schools. It will also be implemented in senior high schools from April 2013. This article presents an overview of the information studies education in the new Course of Study for K-12. Besides, the authors point out what role experts of informatics and information studies education should play in the general education centered around information studies that is meant to help people of the nation to lead an active, powerful, and flexible life until the satisfying end.
The traditional purpose of algorithm in education is to prepare students for programming. In our effort to introduce the practically missing computing science into Czech general secondary education, we have revisited this purpose.We propose an approach, which is in better accordance with the goals of general secondary education in Czechia. The importance of programming is diminishing, while recognition of algorithmic procedures and precise (yet concise) communication of algorithms is gaining importance. This includes expressing algorithms in natural language, which is more useful for most of the students than programming. We propose criteria to evaluate such descriptions. Finally, an idea about the limitations is required (inefficient algorithms, unsolvable problems, Turing’s test). We describe these adjusted educational goals and an outline of the resulting course. Our experience with carrying out the proposed intentions is satisfactory, although we did not accomplish all the defined goals.
We launched an original large-scale experiment concerning informatics learning in French high schools. We are using the France-IOI platform to federate resources and share observation for research. The first step is the implementation of an adaptive hypermedia based on very fine grain epistemic modules for Python programming learning. We define the necessary traces to be built in order to study the trajectories of navigation the pupils will draw across this hypermedia. It may be browsed by pupils either as a course support, or an extra help to solve the list of exercises (mainly for algorithmics discovery). By leaving the locus of control to the learner, we want to observe the different trajectories they finally draw through our system. These trajectories may be abstracted and interpreted as strategies and then compared for their relative efficiency. Our hypothesis is that learners have different profiles and may use the appropriate strategy accordingly. This paper presents the research questions, the method and the expected results.
We shall examine the Pedagogical Content Knowledge (PCK) of Computer Science (CS) teachers concerning students’ Computational Thinking (CT) problem solving skills within the context of a CS course in Dutch secondary education and thus obtain an operational definition of CT and ascertain appropriate teaching methodology. Next we shall develop an instrument to assess students’ CT and design a curriculum intervention geared toward teaching and improving students’ CT problem solving skills and competences. As a result, this research will yield an operational definition of CT, knowledge about CT PCK, a CT assessment instrument and teaching materials and accompanying teacher instructions. It shall contribute to CS teacher education, development of CT education and to education in other (STEM) subjects where CT plays a supporting role, both nationally and internationally.
Informatics as a school subject has been virtually absent from bilingual education programs in German secondary schools. Most bilingual programs in German secondary education started out by focusing on subjects from the field of social sciences. Teachers and bilingual curriculum experts alike have been regarding those as the most suitable subjects for bilingual instruction – largely due to the intercultural perspective that a bilingual approach provides. And though one cannot deny the gain that ensues from an intercultural perspective on subjects such as history or geography, this benefit is certainly not limited to social science subjects. In consequence, bilingual curriculum designers have already begun to include other subjects such as physics or chemistry in bilingual school programs. It only seems a small step to extend this to informatics. This paper will start out by addressing potential benefits of adding informatics to the range of subjects taught as part of English-language bilingual programs in German secondary education. In a second step it will sketch out a methodological (= didactical) model for teaching informatics to German learners through English. It will then provide two items of hands-on and tested teaching material in accordance with this model. The discussion will conclude with a brief outlook on the chances and prerequisites of firmly establishing informatics as part of bilingual school curricula in Germany.
In this paper we report on our experiments in teaching computer science concepts with a mix of tangible and abstract object manipulations. The goal we set ourselves was to let pupils discover the challenges one has to meet to automatically manipulate formatted text. We worked with a group of 25 secondary school pupils (9-10th grade), and they were actually able to “invent” the concept of mark-up language. From this experiment we distilled a set of activities which will be replicated in other classes (6th grade) under the guidance of maths teachers.
We present a concept of better integration of practical teaching in student teacher education in Computer Science. As an introduction to the workshop different possible scenarios are discussed on the basis of examples. Afterwards workshop participants will have the opportunity to discuss the application of the aconcepts in other settings.
Relating to students
(2013)
Deepening understanding
(2013)
Bereits seit Mitte der 1990er Jahre greift die schulische Sprachförderung im Land Berlin vor allem auf das Merkmal der „nichtdeutschen Herkunftssprache“ (ndH) zurück. Mit der Einführung dieses Merkmals entschied sich der Landesgesetzgeber dafür, die – aus seiner Sicht weiterhin dringend notwendige – Sprachförderung von Kindern und Jugendlichen mit Migrationshintergrund in der Schule nicht mehr an eine ausländische Staatsbürgerschaft, sondern, ungeachtet der Staatsbürgerschaft der Schüler, an das Vorherrschen einer nichtdeutschen Kommunikationssprache in der Familie anzuknüpfen. An diesem Ansatz hat sich auch durch die Novellierung des Berliner Schulgesetzes im Jahre 2004 nichts Grundsätzliches geändert. Neben der Bedeutung des Merkmals ‚ndH‘ für die individuelle Sprachförderung in Schulen kommt diesem Merkmal – zusammen mit dem erst unlängst aufgewerteten weiteren Sprachfördermerkmal „Lernmittelbefreiung“ (LmB) – jedoch nunmehr auch eine zentrale Rolle bei der Zumessung von Sprachfördermitteln und Personalressourcen zu. In der Vergangenheit ist das Merkmal ‚ndH‘ allerdings wegen seiner angeblich diskriminierenden und vermeintlich segregierenden Wirkung mehrfach in die Kritik geraten, die sich, ausgelöst durch einen Vorfall an einer Kreuzberger Grundschule im Jahre 2012, noch einmal verstärkt hat. So wird neben der Tatsache, dass das Merkmal ‚ndH‘ überhaupt erhoben und der Sprachförderung zugrunde gelegt wird, auch die Praxis der Berliner Senatsverwaltung für Bildung, Jugend und Wissenschaft, auf den sog. Schulporträts im Internet ‚ndH‘-Quoten zu veröffentlichen, angegriffen und die Abschaffung dieser Praxis gefordert. Ziel der vorliegenden Arbeit ist die Beantwortung der Frage nach der Berechtigung dieser Kritik. Ausgehend von einer Darstellung zur Einführung und Entwicklung des Merkmals ‚ndH‘ unter Berücksichtigung der zuvor geltenden Rechtslage und einer Darstellung der aktuellen rechtlichen Grundlagen der schulischen Sprachförderung im Land Berlin wird dieses Merkmal einer näheren Betrachtung unterzogen. Nach einer Bestimmung des Merkmals ‚ndH‘, einer Erläuterung der einschlägigen Regelungen zur ‚ndH‘-Sprachförderung und einem Vergleich mit dem zusätzlich bestehenden Fördermerkmal ‚LmB‘ im Kontext der aktuellen Bestimmungen wird zunächst ein Überblick über wesentliche Aspekte der schulischen Sprachförderung auf der Grundlage des Merkmals ‚ndH‘ in der Praxis gegeben, in den wiederum das Vergleichsmerkmal ‚LmB‘ einbezogen wird. Daran knüpft die Untersuchung der These an, das Merkmal ‚ndH‘ bzw. zumindest seine Veröffentlichung im Rahmen der Schulporträts der Senatsschulverwaltung habe diskriminierende Wirkung und führe zu einer Segregation der Schülerschaft. Im Anschluss daran wird als zusätzliche Überlegung der Frage nach der tatsächlichen Notwendigkeit einer sich an dem Merkmal ‚ndH‘ und damit einer familiären Kommunikationssprache orientierenden Sprachförderung nachgegangen, die, wenn sie denn bejaht werden könnte, etwaige Diskriminierungs- und Segregationswirkungen rechtfertigte.
Information flows in EU policy-making are heavily dependent on personal networks, both within the Brussels sphere but also reaching outside the narrow limits of the Belgian capital. These networks develop for example in the course of formal and informal meetings or at the sidelines of such meetings. A plethora of committees at European, transnational and regional level provides the basis for the establishment of pan-European networks. By studying affiliation to those committees, basic network structures can be uncovered. These affiliation network structures can then be used to predict EU information flows, assuming that certain positions within the network are advantageous for tapping into streams of information while others are too remote and peripheral to provide access to information early enough. This study has tested those assumptions for the case of the reform of the Common Fisheries Policy for the time after 2012. Through the analysis of an affiliation network based on participation in 10 different fisheries policy committees over two years (2009 and 2010), network data for an EU-wide network of about 1300 fisheries interest group representatives and more than 200 events was collected. The structure of this network showed a number of interesting patterns, such as – not surprisingly – a rather central role of Brussels-based committees but also close relations of very specific interests to the Brussels-cluster and stronger relations between geographically closer maritime regions. The analysis of information flows then focused on access to draft EU Commission documents containing the upcoming proposal for a new basic regulation of the Common Fisheries Policy. It was first documented that it would have been impossible to officially obtain this document and that personal networks were thus the most likely sources for fisheries policy actors to obtain access to these “leaks” in early 2011. A survey of a sample of 65 actors from the initial network supported these findings: Only a very small group had accessed the draft directly from the Commission. Most respondents who obtained access to the draft had received it from other actors, highlighting the networked flow of informal information in EU politics. Furthermore, the testing of the hypotheses connecting network positions and the level of informedness indicated that presence in or connections to the Brussels sphere had both advantages for overall access to the draft document and with regard to timing. Methodologically, challenges of both the network analysis and the analysis of information flows but also their relevance for the study of EU politics have been documented. In summary, this study has laid the foundation for a different way to study EU policy-making by connecting topical and methodological elements – such as affiliation network analysis and EU committee governance – which so far have not been considered together, thereby contributing in various ways to political science and EU studies.
Im September 2009 fand der 5. Potsdamer Lateintag statt. Er war Bestandteil des auf drei Jahre angelegten Brandenburger Antike-Denkwerks (BrAnD), das von der Robert Bosch Stiftung gefördert wurde. Thema war dieses Mal: Macht und Ohnmacht der Worte – Gesellschaft und Rhetorik. Aus der Antike stammen nicht nur die heute noch benutzten Rhetoriktheorien und -anweisungen. Auch das reziproke Verhältnis von Gesellschaft und Rhetorik wurde hier vorgelebt und vorgedacht. Es sollte mit antiken Rhetoriklehren vertraut gemacht werden, antike Reden auf deren Umsetzung und auf ihre Wirkung betrachtet und die Möglichkeit einer heutigen Umsetzung überprüft werden. Der Band versammelt die Vorträge des Lateintags von Herrn Prof. Dr. P. Riemer und Herrn Prof. A. Fritsch, die Darstellung zum Ablauf des gesamten Projekts sowie eine Auswahl der Berichte zu den Schulprojekten.
In the presence of a solid-liquid or liquid-air interface, bacteria can choose between a planktonic and a sessile lifestyle. Depending on environmental conditions, cells swimming in close proximity to the interface can irreversibly attach to the surface and grow into three-dimensional aggregates where the majority of cells is sessile and embedded in an extracellular polymer matrix (biofilm). We used microfluidic tools and time lapse microscopy to perform experiments with the polarly flagellated soil bacterium Pseudomonas putida (P. putida), a bacterial species that is able to form biofilms. We analyzed individual trajectories of swimming cells, both in the bulk fluid and in close proximity to a glass-liquid interface. Additionally, surface related growth during the early phase of biofilm formation was investigated. In the bulk fluid, P.putida shows a typical bacterial swimming pattern of alternating periods of persistent displacement along a line (runs) and fast reorientation events (turns) and cells swim with an average speed around 24 micrometer per second. We found that the distribution of turning angles is bimodal with a dominating peak around 180 degrees. In approximately six out of ten turning events, the cell reverses its swimming direction. In addition, our analysis revealed that upon a reversal, the cell systematically changes its swimming speed by a factor of two on average. Based on the experimentally observed values of mean runtime and rotational diffusion, we presented a model to describe the spreading of a population of cells by a run-reverse random walker with alternating speeds. We successfully recover the mean square displacement and, by an extended version of the model, also the negative dip in the directional autocorrelation function as observed in the experiments. The analytical solution of the model demonstrates that alternating speeds enhance a cells ability to explore its environment as compared to a bacterium moving at a constant intermediate speed. As compared to the bulk fluid, for cells swimming near a solid boundary we observed an increase in swimming speed at distances below d= 5 micrometer and an increase in average angular velocity at distances below d= 4 micrometer. While the average speed was maximal with an increase around 15% at a distance of d= 3 micrometer, the angular velocity was highest in closest proximity to the boundary at d=1 micrometer with an increase around 90% as compared to the bulk fluid. To investigate the swimming behavior in a confinement between two solid boundaries, we developed an experimental setup to acquire three-dimensional trajectories using a piezo driven objective mount coupled to a high speed camera. Results on speed and angular velocity were consistent with motility statistics in the presence of a single boundary. Additionally, an analysis of the probability density revealed that a majority of cells accumulated near the upper and lower boundaries of the microchannel. The increase in angular velocity is consistent with previous studies, where bacteria near a solid boundary were shown to swim on circular trajectories, an effect which can be attributed to a wall induced torque. The increase in speed at a distance of several times the size of the cell body, however, cannot be explained by existing theories which either consider the drag increase on cell body and flagellum near a boundary (resistive force theory) or model the swimming microorganism by a multipole expansion to account for the flow field interaction between cell and boundary. An accumulation of swimming bacteria near solid boundaries has been observed in similar experiments. Our results confirm that collisions with the surface play an important role and hydrodynamic interactions alone cannot explain the steady-state accumulation of cells near the channel walls. Furthermore, we monitored the number growth of cells in the microchannel under medium rich conditions. We observed that, after a lag time, initially isolated cells at the surface started to grow by division into colonies of increasing size, while coexisting with a comparable smaller number of swimming cells. After 5:50 hours, we observed a sudden jump in the number of swimming cells, which was accompanied by a breakup of bigger clusters on the surface. After approximately 30 minutes where planktonic cells dominated in the microchannel, individual swimming cells reattached to the surface. We interpret this process as an emigration and recolonization event. A number of complementary experiments were performed to investigate the influence of collective effects or a depletion of the growth medium on the transition. Similar to earlier observations on another bacterium from the same family we found that the release of cells to the swimming phase is most likely the result of an individual adaption process, where syntheses of proteins for flagellar motility are upregulated after a number of division cycles at the surface.
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 Arbeit widmet sich dem kontroversen Diskurs über den Schutz von Urheberrechten einerseits und den freien Zugang zu Ressourcen über das Internet andererseits. Auf Grundlage eines Korpus aus mündlichen sowie schriftlichen Textdaten werden drei zentrale Ziele verfolgt: Erstens werden die Identitätskonstruktionen der Teilnehmer innerhalb des gewählten Diskursausschnittes analysiert. Zweitens werden Zusammenhänge zwischen Mikro- und Makroebene, d. h. zwischen Identitätskonstruktion auf lokaler Gesprächsebene und solcher auf der globaleren Ebene des schriftlichen Datenmaterials untersucht. Drittens werden die eingesetzten Analyseinstrumente aus verschiedenen sprachwissenschaftlichen Disziplinen auf ihre Anwendbarkeit für eine ebenenübergreifende Studie bewertet. Die Arbeit bewegt sich damit in ihrer Methodik zwischen zwei kommunikationslinguistischen Forschungsperspektiven, der Konversationsanalyse und der Diskursanalyse, die bisher im deutschen Forschungsraum noch eher getrennte Wege gegangen sind.
In this work, thermosensitive hydrogels having tunable thermo-mechanical properties were synthesized. Generally the thermal transition of thermosensitive hydrogels is based on either a lower critical solution temperature (LCST) or critical micelle concentration/ temperature (CMC/ CMT). The temperature dependent transition from sol to gel with large volume change may be seen in the former type of thermosensitive hydrogels and is negligible in CMC/ CMT dependent systems. The change in volume leads to exclusion of water molecules, resulting in shrinking and stiffening of system above the transition temperature. The volume change can be undesired when cells are to be incorporated in the system. The gelation in the latter case is mainly driven by micelle formation above the transition temperature and further colloidal packing of micelles around the gelation temperature. As the gelation mainly depends on concentration of polymer, such a system could undergo fast dissolution upon addition of solvent. Here, it was envisioned to realize a thermosensitive gel based on two components, one responsible for a change in mechanical properties by formation of reversible netpoints upon heating without volume change, and second component conferring degradability on demand. As first component, an ABA triblockcopolymer (here: Poly(ethylene glycol)-b-poly(propylene glycol)-b-poly(ethylene glycol) (PEPE) with thermosensitive properties, whose sol-gel transition on the molecular level is based on micellization and colloidal jamming of the formed micelles was chosen, while for the additional macromolecular component crosslinking the formed micelles biopolymers were employed. The synthesis of the hydrogels was performed in two ways, either by physical mixing of compounds showing electrostatic interactions, or by covalent coupling of the components. Biopolymers (here: the polysaccharides hyaluronic acid, chondroitin sulphate, or pectin, as well as the protein gelatin) were employed as additional macromolecular crosslinker to simultaneously incorporate an enzyme responsiveness into the systems. In order to have strong ionic/electrostatic interactions between PEPE and polysaccharides, PEPE was aminated to yield predominantly mono- or di-substituted PEPEs. The systems based on aminated PEPE physically mixed with HA showed an enhancement in the mechanical properties such as, elastic modulus (G′) and viscous modulus (G′′) and a decrease of the gelation temperature (Tgel) compared to the PEPE at same concentration. Furthermore, by varying the amount of aminated PEPE in the composition, the Tgel of the system could be tailored to 27-36 °C. The physical mixtures of HA with di-amino PEPE (HA·di-PEPE) showed higher elastic moduli G′ and stability towards dissolution compared to the physical mixtures of HA with mono-amino PEPE (HA·mono-PEPE). This indicates a strong influence of electrostatic interaction between –COOH groups of HA and –NH2 groups of PEPE. The physical properties of HA with di-amino PEPE (HA·di-PEPE) compare beneficially with the physical properties of the human vitreous body, the systems are highly transparent, and have a comparable refractive index and viscosity. Therefore,this material was tested for a potential biological application and was shown to be non-cytotoxic in eluate and direct contact tests. The materials will in the future be investigated in further studies as vitreous body substitutes. In addition, enzymatic degradation of these hydrogels was performed using hyaluronidase to specifically degrade the HA. During the degradation of these hydrogels, increase in the Tgel was observed along with decrease in the mechanical properties. The aminated PEPE were further utilised in the covalent coupling to Pectin and chondroitin sulphate by using EDC as a coupling agent. Here, it was possible to adjust the Tgel (28-33 °C) by varying the grafting density of PEPE to the biopolymer. The grafting of PEPE to Pectin enhanced the thermal stability of the hydrogel. The Pec-g-PEPE hydrogels were degradable by enzymes with slight increase in Tgel and decrease in G′ during the degradation time. The covalent coupling of aminated PEPE to HA was performed by DMTMM as a coupling agent. This method of coupling was observed to be more efficient compared to EDC mediated coupling. Moreover, the purification of the final product was performed by ultrafiltration technique, which efficiently removed the unreacted PEPE from the final product, which was not sufficiently achieved by dialysis. Interestingly, the final products of these reaction were in a gel state and showed enhancement in the mechanical properties at very low concentrations (2.5 wt%) near body temperature. In these hydrogels the resulting increase in mechanical properties was due to the combined effect of micelle packing (physical interactions) by PEPE and covalent netpoints between PEPE and HA. PEPE alone or the physical mixtures of the same components were not able to show thermosensitive behavior at concentrations below 16 wt%. These thermosensitive hydrogels also showed on demand solubilisation by enzymatic degradation. The concept of thermosensitivity was introduced to 3D architectured porous hydrogels, by covalently grafting the PEPE to gelatin and crosslinking with LDI as a crosslinker. Here, the grafted PEPE resulted in a decrease in the helix formation in gelatin chains and after fixing the gelatin chains by crosslinking, the system showed an enhancement in the mechanical properties upon heating (34-42 °C) which was reversible upon cooling. A possible explanation of the reversible changes in mechanical properties is the strong physical interactions between micelles formed by PEPE being covalently linked to gelatin. Above the transition temperature, the local properties were evaluated by AFM indentation of pore walls in which an increase in elastic modulus (E) at higher temperature (37 °C) was observed. The water uptake of these thermosensitive architectured porous hydrogels was also influenced by PEPE and temperature (25 °C and 37 °C), showing lower water up take at higher temperature and vice versa. In addition, due to the lower water uptake at high temperature, the rate of hydrolytic degradation of these systems was found to be decreased when compared to pure gelatin architectured porous hydrogels. Such temperature sensitive architectured porous hydrogels could be important for e.g. stem cell culturing, cell differentiation and guided cell migration, etc. Altogether, it was possible to demonstrate that the crosslinking of micelles by a macromolecular crosslinker increased the shear moduli, viscosity, and stability towards dissolution of CMC-based gels. This effect could be likewise be realized by covalent or non-covalent mechanisms such as, micelle interactions, physical interactions of gelatin chains and physical interactions between gelatin chains and micelles. Moreover, the covalent grafting of PEPE will create additional net-points which also influence the mechanical properties of thermosensitive architectured porous hydrogels. Overall, the physical and chemical interactions and reversible physical interactions in such thermosensitive architectured porous hydrogels gave a control over the mechanical properties of such complex system. The hydrogels showing change of mechanical properties without a sol-gel transition or volume change are especially interesting for further study with cell proliferation and differentiation.
It was the goal of this work to explore two different synthesis pathways using green chemistry. The first part of this thesis is focusing on the use of the urea-glass route towards single phase manganese nitride and manganese nitride/oxide nano-composites embedded in carbon, while the second part of the thesis is focusing on the use of the “saccharide route” (namely cellulose, sucrose, glucose and lignin) towards metal (Ni0), metal alloy (Pd0.9Ni0.1, Pd0.5Ni0.5, Fe0.5Ni0.5, Cu0.5Ni0.5 and W0.15Ni0.85) and ternary carbide (Mn0.75Fe2.25C) nanoparticles embedded in carbon. In the interest of battery application, MnN0.43 nanoparticles surrounded by a graphitic shell and embedded in carbon with a high surface area (79 m^2/g) were synthesized, following a previously set route.The comparison of the material characteristics before and after the discharge showed no remarkable difference in terms of composition and just slight differences in the morphological point of view, meaning the particles are stable but agglomerate. The graphitic shell is contributing to the resistance of the material and leads to a fine cyclic stability over 140 cycles of 230 mAh/g after the first charge/discharge and coulombic efficiencies close to 100%. Due to the low voltage towards Li/Li+ and the low polarization, it might be an attractive anode material for lithium ion batteries. However, the capacity is still noticeably lower than the theoretical value for MnN0.43. A mixture of MnN0.43 and MnO nanoparticles embedded in carbon (surface area 93 m^2/g) was able to improve the cyclic stability to over 160 cycles giving a capacity of 811 mAh/g, which is considerably higher than the capacity of the conventional material graphite (372 mAh/g). This nano-composite seems to agglomerate less during the process of discharge. Interestingly, although the capacity is much higher than of the single phase manganese nitride, the nano-composite seems to only contain MnN0.43 nanoparticles after the process of discharge with no oxide phase to be found. Concerning catalysis application, different metal, metal alloy, and metal carbide nanoparticles were synthesized using the saccharide route. At first, systems that were already investigated before, being Pd0.9Ni0.1, Pd0.5Ni0.5, Fe0.5Ni0.5 and Mn0.75Fe2.25C using cellulose as the carbon source were prepared and tested in an alkylation reaction of toluene with benzylchloride. Unexpectedly, the metal alloys did not show any catalytic activity, but the ternary carbide Mn0.75Fe2.25C showed fine catalytic activity of 98% conversion after 9 hour reaction time (110 °C). In a second step, the saccharide route was modified towards other carbon sources and carbon to metal ratios in order to improve the homogeneity of the samples and accessibility of the particle surfaces. The used carbon sources sucrose and glucose are similar in their basic structure of carbohydrates, but reducing the (polymeric) chain length. Indeed, the cellulose could be successfully replaced by sucrose and glucose. A lower carbon to metal ratio was found to influence the size, homogeneity and accessibility (as evidenced by TEM) of the samples. Since sucrose is an aliment, glucose is the better choice as a carbon source. Using glucose, the synthesis of Cu0.5Ni0.5 and W0.15Ni0.85 nano-composites was also possible, although the later was never obtained as pure phase. These alloy nano-composites were tested, along with nickel0 nanoparticles also prepared with glucose and on their catalytic activity towards the reduction of phenylacetylene. The results obtained let believe that any (poly) saccharide, including lignin, could be used as carbon source. The nickel0 nano-composites prepared with lignin as a carbon source were tested along with those prepared with cellulose and sucrose for their catalytic activity in the transfer hydrogenation of nitrobenzene (results compared with exposed nickel nanoparticles and nickel supported on carbon) leading to very promising results. Based on the urea-glass route and the saccharide route, simple equipment and transition metals, it was possible to have a one-pot synthesize with scale-up possibilities towards new material that can be applied in catalysis and battery systems.
The Prussian geologist Leopold von Buch was a lifelong friend of Alexander von Humboldt and had a significant influence on Humboldt’s geological ideas. In a talk, held in Berlin in 1831, which is published here for the first time, von Buch presented the Duria Antiquior of 1830 by the English geologist Henry De La Beche. The Duria Antiquior is widely regarded as the earliest depiction of a scene of prehistoric life from deep time. The print raised new questions about the processes of geohistorical change. The talk reveals that Leopold von Buch was a true scientist of the Romantic Age. His descriptions of geohistorical organismic transformations are taken from pictorial examples of organismic transformation from the classical literature. The talk also illustrates how influential English geologists were for geo-historical reconstructions in Germany.
This thesis gives formal definitions of discourse-givenness, coreference and reference, and reports on experiments with computational models of discourse-givenness of noun phrases for English and German. Definitions are based on Bach's (1987) work on reference, Kibble and van Deemter's (2000) work on coreference, and Kamp and Reyle's Discourse Representation Theory (1993). For the experiments, the following corpora with coreference annotation were used: MUC-7, OntoNotes and ARRAU for Englisch, and TueBa-D/Z for German. As for classification algorithms, they cover J48 decision trees, the rule based learner Ripper, and linear support vector machines. New features are suggested, representing the noun phrase's specificity as well as its context, which lead to a significant improvement of classification quality.
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.
Intensive Forschung hat in den vergangenen Jahrzehnten zu einer sehr detaillierten Charakterisierung des Geschmackssystems der Säugetiere geführt. Dennoch sind mit den bislang eingesetzten Methoden wichtige Fragestellungen unbeantwortet geblieben. Eine dieser Fragen gilt der Unterscheidung von Bitterstoffen. Die Zahl der Substanzen, die für den Menschen bitter schmecken und in Tieren angeborenes Aversionsverhalten auslösen, geht in die Tausende. Diese Substanzen sind sowohl von der chemischen Struktur als auch von ihrer Wirkung auf den Organismus sehr verschieden. Während viele Bitterstoffe potente Gifte darstellen, sind andere in den Mengen, die mit der Nahrung aufgenommen werden, harmlos oder haben sogar positive Effekte auf den Körper. Zwischen diesen Gruppen unterscheiden zu können, wäre für ein Tier von Vorteil. Ein solcher Mechanismus ist jedoch bei Säugetieren nicht bekannt. Das Ziel dieser Arbeit war die Untersuchung der Verarbeitung von Geschmacksinformation in der ersten Station der Geschmacksbahn im Mausgehirn, dem Nucleus tractus solitarii (NTS), mit besonderem Augenmerk auf der Frage nach der Diskriminierung verschiedener Bitterstoffe. Zu diesem Zweck wurde eine neue Untersuchungsmethode für das Geschmackssystem etabliert, die die Nachteile bereits verfügbarer Methoden umgeht und ihre Vorteile kombiniert. Die Arc-catFISH-Methode (cellular compartment analysis of temporal activity by fluorescent in situ hybridization), die die Charakterisierung der Antwort großer Neuronengruppen auf zwei Stimuli erlaubt, wurde zur Untersuchung geschmacksverarbeitender Zellen im NTS angewandt. Im Zuge dieses Projekts wurde erstmals eine stimulusinduzierte Arc-Expression im NTS gezeigt. Die ersten Ergebnisse offenbarten, dass die Arc-Expression im NTS spezifisch nach Stimulation mit Bitterstoffen auftritt und sich die Arc exprimierenden Neurone vornehmlich im gustatorischen Teil des NTS befinden. Dies weist darauf hin, dass Arc-Expression ein Marker für bitterverarbeitende gustatorische Neurone im NTS ist. Nach zweimaliger Stimulation mit Bittersubstanzen konnten überlappende, aber verschiedene Populationen von Neuronen beobachtet werden, die unterschiedlich auf die drei verwendeten Bittersubstanzen Cycloheximid, Chininhydrochlorid und Cucurbitacin I reagierten. Diese Neurone sind vermutlich an der Steuerung von Abwehrreflexen beteiligt und könnten so die Grundlage für divergentes Verhalten gegenüber verschiedenen Bitterstoffen bilden.
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.
In this work, the development of temperature- and protein-responsive sensor materials based on biocompatible, inverse hydrogel opals (IHOs) is presented. With these materials, large biomolecules can be specifically recognised and the binding event visualised. The preparation of the IHOs was performed with a template process, for which monodisperse silica particles were vertically deposited onto glass slides as the first step. The obtained colloidal crystals with a thickness of 5 μm displayed opalescent reflections because of the uniform alignment of the colloids. As a second step, the template was embedded in a matrix consisting of biocompatible, thermoresponsive hydrogels. The comonomers were selected from the family of oligo(ethylene glycol)methacrylates. The monomer solution was injected into a polymerisation mould, which contained the colloidal crystals as a template. The space in-between the template particles was filled with the monomer solution and the hydrogel was cured via UV-polymerisation. The particles were chemically etched, which resulted in a porous inner structure. The uniform alignment of the pores and therefore the opalescent reflection were maintained, so these system were denoted as inverse hydrogel opals. A pore diameter of several hundred nanometres as well as interconnections between the pores should facilitate a diffusion of bigger (bio)molecules, which was always a challenge in the presented systems until now. The copolymer composition was chosen to result in a hydrogel collapse over 35 °C. All hydrogels showed pronounced swelling in water below the critical temperature. The incorporation of a reactive monomer with hydroxyl groups ensured a potential coupling group for the introduction of recognition units for analytes, e.g. proteins. As a test system, biotin as a recognition unit for avidin was coupled to the IHO via polymer-analogous Steglich esterification. The amount of accessible biotin was quantified with a colorimetric binding assay. When avidin was added to the biotinylated IHO, the wavelength of the opalescent reflection was significantly shifted and therefore the binding event was visualised. This effect is based on the change in swelling behaviour of the hydrogel after binding of the hydrophilic avidin, which is amplified by the thermoresponsive nature of the hydrogel. A swelling or shrinking of the pores induces a change in distance of the crystal planes, which are responsible for the colour of the reflection. With these findings, the possibility of creating sensor materials or additional biomolecules in the size range of avidin is given.
Landslides are one of the biggest natural hazards in Georgia, a mountainous country in the Caucasus. So far, no systematic monitoring and analysis of the dynamics of landslides in Georgia has been made. Especially as landslides are triggered by extrinsic processes, the analysis of landslides together with precipitation and earthquakes is challenging. In this thesis I describe the advantages and limits of remote sensing to detect and better understand the nature of landslide in Georgia. The thesis is written in a cumulative form, composing a general introduction, three manuscripts and a summary and outlook chapter. In the present work, I measure the surface displacement due to active landslides with different interferometric synthetic aperture radar (InSAR) methods. The slow landslides (several cm per year) are well detectable with two-pass interferometry. In same time, the extremely slow landslides (several mm per year) could be detected only with time series InSAR techniques. I exemplify the success of InSAR techniques by showing hitherto unknown landslides, located in the central part of Georgia. Both, the landslide extent and displacement rate is quantified. Further, to determine a possible depth and position of potential sliding planes, inverse models were developed. Inverse modeling searches for parameters of source which can create observed displacement distribution. I also empirically estimate the volume of the investigated landslide using displacement distributions as derived from InSAR combined with morphology from an aerial photography. I adapted a volume formula for our case, and also combined available seismicity and precipitation data to analyze potential triggering factors. A governing question was: What causes landslide acceleration as observed in the InSAR data? The investigated area (central Georgia) is seismically highly active. As an additional product of the InSAR data analysis, a deformation area associated with the 7th September Mw=6.0 earthquake was found. Evidences of surface ruptures directly associated with the earthquake could not be found in the field, however, during and after the earthquake new landslides were observed. The thesis highlights that deformation from InSAR may help to map area prone landslides triggering by earthquake, potentially providing a technique that is of relevance for country wide landslide monitoring, especially as new satellite sensors will emerge in the coming years.
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.
Under standard conditions the cross metathesis of allyl alcohols and methyl acrylate is accompanied by the formation of ketones, resulting from uncontrolled and undesired double bond isomerization. By conducting the CM in the presence of phenol, the catalyst loading and the reaction time required for quantiative conversion can be reduced, and isomerization can be suppressed. On the other hand, consecutive isomerization can be deliberately promoted by evaporating excess methyl acrylate after completing cross metathesis and by adding a base or silane as chemical triggers.
With the present theoretical study of the photochemical switching of E-methylfurylfulgide we contribute an important step towards the understanding of the photochemical processes in furylfulgide-related molecules. We have carried out large-scale, full-dimensional direct semiempirical configuration-interaction surface-hopping dynamics of the photoinduced ring-closure reaction. Simulated static and dynamical UV/Vis-spectra show good agreement with experimental data of the same molecule. By a careful investigation of our dynamical data, we were able to identify marked differences to the dynamics of the previously studied E-isopropylfurylfulgide. With our simulations we can not only reproduce the experimentally observed quantum yield differences qualitatively but we can also pinpoint two reasons for them: kinematics and pre-orientation. With our analysis, we thus offer straightforward molecular explanations for the high sensitivity of the photodynamics towards seemingly minor changes in molecular constitution. Beyond the realm of furylfulgides, these insights provide additional guidance to the rational design of photochemically switchable molecules.
Intracellular photoactivation of caged cGMP induces myosin II and actin responses in motile cells
(2013)
Cyclic GMP (cGMP) is a ubiquitous second messenger in eukaryotic cells. It is assumed to regulate the association of myosin II with the cytoskeleton of motile cells. When cells of the social amoeba Dictyostelium discoideum are exposed to chemoattractants or to increased osmotic stress, intracellular cGMP levels rise, preceding the accumulation of myosin II in the cell cortex. To directly investigate the impact of intracellular cGMP on cytoskeletal dynamics in a living cell, we released cGMP inside the cell by laser-induced photo-cleavage of a caged precursor. With this approach, we could directly show in a live cell experiment that an increase in intracellular cGMP indeed induces myosin II to accumulate in the cortex. Unexpectedly, we observed for the first time that also the amount of filamentous actin in the cell cortex increases upon a rise in the cGMP concentration, independently of cAMP receptor activation and signaling. We discuss our results in the light of recent work on the cGMP signaling pathway and suggest possible links between cGMP signaling and the actin system.
Continuous synthesis of pyridocarbazoles and initial photophysical and bioprobe characterization
(2013)
Pyridocarbazoles when ligated to transition metals yield high affinity kinase inhibitors. While batch photocyclizations enable the synthesis of these heterocycles, the non-oxidative Mallory reaction only provides modest yields and difficult to purify mixtures. We demonstrate here that a flow-based Mallory cyclization provides superior results and enables observation of a clear isobestic point. The flow method allowed us to rapidly synthesize ten pyridocarbazoles and for the first time to document their interesting photophysical attributes. Preliminary characterization reveals that these molecules might be a new class of fluorescent bioprobe.
Dispositive zeichnen sich aus durch einen phantasmatischen und affektorientierten Bezug, den das Subjekt zu ihnen herstellt und in dem es sich konstituiert. Dispositive stellen das Movens zur Verfügung, das zur immer neuen Aktualisierung dieses Bezugs verführt. Paris, Berlin, Charleroi - die Beiträge dieses Bandes lassen die Stadt als Dispositiv der Literatur zutage treten. Sie verhandeln dessen Hybridität und Heterogenität, sie reflektieren es als Produktions- und Rezeptionsstätte von Literatur, Philosophie und Kritik. Schriftsteller erfinden und zerstören Städte. Ihre Texte sind auch dort städtisch, wo gar nicht von der Stadt gesprochen wird. Die Stadt als Dispositiv manifestiert sich auch als Non-Dit des literarischen und philosophischen Diskurses.
In den romanischen Sprachen stehen Verbalmodi, Modalverben, Modaladverbien und Modalpartikeln zum Ausdruck von Modalität zur Verfügung, die schon häufig mit dem Deutschen verglichen wurden. In diesem Beitrag soll es um Entsprechungen versteckter, sogenannter coverter Modalität gehen (vgl. Abraham / Leiss 2012, Haßler 2012). Zunächst soll das Verständnis von Modalität dargelegt werden, um dann ihre coverten Formen einzuordnen. Die gegenseitigen Entsprechungen werden an Beispielen analysiert und schließlich wird ein Vorschlag entwickelt, wie die Mittel der Modalisierung als sprachspezifisch und zu einem Kontinuum gehörend beschrieben werden können.
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.
Les représentants du relativisme linguistique du XXème siècle qui se réclament de l’histoire de leur théorie mentionnent normalement Guillaume de Humboldt comme initiateur de l’idée que la manière particulière de penser d’un peuple dépendrait de sa langue. La théorie de Humboldt s’avère, cependant, difficilement maniable dans la recherche linguistique. Malgré une similitude évidente dans certaines positions, comme par exemple les concepts d’‘articulation’ et de ‘valeur’, le renouvellement de la linguistique sur une base saussurienne, au début du XXème siècle, se passait des idées de Humboldt. Il n’y avait que quelques philologues ‘idéalistes’ qui poursuivaient ce type de recherche. Ainsi, Karl Vossler constatait un parallélisme entre la langue et la culture et les considérait comme résultats de la création humaine. Le mécontentement quant à la description des langues selon le paradigme positiviste des néogrammairiens s’articulait nettement.
Le concept d’une vision linguistique du monde fut développé dans la théorie des néohumboldtiens (Weisgerber, Trier et autres) qui affirmaient que l’individu s’approprie le monde à travers la langue. Des différences entre des langues influeraient considérablement sur les facultés cognitives des hommes et sur leur comportement. L’idée humboldtienne de l’energeia se trouvait exclue de ces théories qui aspiraient à un renouvellement de la langue maternelle dans le sens d’une ‘grammaire à partir du contenu’ (inhaltbezogene Grammatik). Ce type de réflexion linguistique se prêtait aussi à une utilisation politique sous le national-socialisme. La théorie de Weisgerber, déclarée comme antiraciste et anti-national-socialiste par l’auteur lui-même, fut considérée comme « mother-tongue fascism » par Christopher Hutton. La relation entre le relativisme linguistique et la doctrine nationale-socialiste est évidente dans les écrits de plusieurs auteurs, par exemple dans « notre langue maternelle comme arme et instrument de la pensée allemande » de Georg Schmidt-Rohr. Il y eut des implications racistes de la théorie de quelques indo-germanistes bien avant 1933.
L’influence des néohumboldtiens s’est poursuivie jusqu’aux années 60, époque où ils durent faire place à des linguistes structuralistes et générativistes. On trouve dans quelques vérifications plus récentes du relativisme linguistique des références à des textes antérieurs à Humboldt. Par exemple, Gumperz et Levison (1996) citent le concours de l’Académie de Berlin sur la question suivante : Quelle est l'influence réciproque des opinions du peuple sur le langage et du langage sur les opinions? Est-ce que cet élargissement de l’horizon de rétrospection a quelque chose à voir avec la conscience d’une portée sociale possible de cette théorie ?
Von wegen Kinderspiel
(2013)
Chillen gestern
(2013)
Folgt tatsächlich aus einem liberalen Wertekanon eine generative Selbstbestimmung, eine weitgehende elterliche Handlungsfreiheit bei eugenischen Maßnahmen, wie es Vertreter einer „liberalen Eugenik“ versichern? Diese Arbeit diskutiert die Rolle Staates und die Handlungsspielräume der Eltern bei der genetischen Gestaltung von Nachkommen im Rahmen eines liberalen Wertverständnisses.
Den Schwerpunkt/Fokus der Betrachtungen liegt hier Maßnahmen des genetic enhancement.
Darüber hinaus wird auch das Verhältnis der „liberalen Eugenik“ zur „autoritären Eugenik“ neu beleuchtet.
Die Untersuchung beginnt bei der Analyse zentraler liberaler Werte und Normen, wie Freiheit, Autonomie und Gerechtigkeit und deren Funktionen in der „liberalen Eugenik“. Wobei nur sehr eingeschränkt von der „liberalen Eugenik“ gesprochen werden kann, sondern viel mehr von Varianten einer „liberalen Eugenik“.
Darüber hinaus wird in dieser Arbeit die historische Entwicklung der „liberalen“ und der „autoritären Eugenik“, speziell des Sozialdarwinismus, untersucht und verglichen, insbesondere im Hinblick auf liberale Werte und Normen und der generativen Selbstbestimmung.
Den Kern der Arbeit bildet der Vergleich der „liberalen Eugenik“ mit der „liberalen Erziehung“. Da hier die grundlegenden Aufgaben der Eltern, aber auch des Staates, analysiert und deren Verhältnis diskutiert wird.
Es zeigt sich, dass sich aus einem liberalen Wertverständnisses heraus keine umfangreiche generative Selbstbestimmung ableiten lässt, sondern sich viel mehr staatlich kontrollierte enge Grenzen bei eugenischen Maßnahmen zum Wohle der zukünftigen Person, begründen.
Zudem wurde der Weg zur autoritären Eugenik nicht durch die Abkehr von der generativen Selbstbestimmung geebnet, sondern viel mehr durch die Übertragung des Fortschrittsgedankens auf den Menschen selbst. Damit verliert die generative Selbstbestimmung auch ihre Funktion als Brandmauer gegen eine autoritäre Eugenik. Nicht der Verlust der generativen Selbstbestimmung, sondern viel mehr die Idee der Perfektionierung des Menschen muss kritisch betrachtet und letztlich abgelehnt werden.
Ohne generative Selbstbestimmung und einer Perfektionierung des Menschen, bleibt nur eine Basis-Eugenik, bei der die Entwicklungsfähigkeit des Menschen sichergestellt wird, nicht jedoch seine Verbesserung.
Darüber hinaus muss auch über eine Entwicklungsmöglichkeit des zukünftigen Menschen gesprochen werden, d. h. ein minimales Potential zu gesellschaftlicher Integration muss gegeben sein. Nur wenn tatsächlich keine Möglichkeiten seitens der Gesellschaft bestehen eine Person zu integrieren und dieser eine Entwicklungsmöglichkeit zu bieten, wären eugenische Maßnahmen als letztes Mittel akzeptabel.
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.
Ein konstruktivistischer Lehransatz für die Einführungsveranstaltung der Theoretische Informatik
(2013)
The PSM-leadership fit
(2013)
This article examines the use of performance information by public managers. It conceptualizes purposeful data use as a type of extra-role behaviour which requires additional effort on the part of the managers and which is not extrinsically rewarded. The article sheds light on one potential antecedent of performance information use – the motivation of the users. It argues that we can observe high levels of data use if managers driven by public service motivation (PSM) work under transformational leaders. Using a needs-supply perspective on supervisors and followers we suggest that there is a PSM-leadership fit which fosters the performance of this extra-role behaviour. The article is based on data from German local government and its findings contribute to the literatures on PSM as well as on performance management.
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.
Adipositas ist eine chronische Erkrankung mit erheblichen Komorbiditäten und Folgeschäden, die bereits im Kindes- und Jugendalter weit verbreitet ist. Unterschiedliche Faktoren sind an der Ätiologie dieser Störung beteiligt. Die Ernährung stellt dabei eine der Hauptsäulen dar, auf welche immer wieder Bezug genommen wird. Der Einfluss der Eltern auf die kindliche Ernährung spielt unbestritten eine zentrale Rolle – hinsichtlich genetischer Dispositionen, aber auch als Gestalter der Lebensumwelten und Vorbilder im Ernährungsbereich. Die vorliegende Arbeit hat zum Ziel, Übereinstimmungen elterlicher und kindlicher Ernährung zu untersuchen und dabei zu prüfen, inwiefern Prozesse des Modelllernens für die Zusammenhänge verantwortlich zeichnen. Grundlage ist die sozial-kognitive Theorie Albert Banduras mit dem Fokus auf seinen Ausführungen zum Beobachtungs- oder Modelllernen. Die Zusammenhänge elterlicher und kindlicher Ernährung wurden anhand einer Stichprobe 7 – 13-jähriger adipöser Kinder und ihrer Eltern in Beziehung gesetzt zu den Bedingungen des Modelllernens, die zuvor auch in anderen Studien gefunden worden waren. Eine hohe Ähnlichkeit oder gute Beziehung zwischen Modell (Mutter bzw. Vater) und Lernendem (Kind) sollte demnach moderierend auf die Stärke des Zusammenhangs wirken. Aus Banduras Ausführungen zu den Phasen des Modelllernens ergibt sich zudem ein dritter Aspekt, der in das Untersuchungsmodell einbezogen wurde. Die von Bandura postulierte Aneignungsphase setzt voraus, dass das zu lernende Verhalten auch beobachtet werden kann. Aus diesem Grund sollte die Analyse von Zusammenhängen im Verhalten nicht losgelöst von der Zeit betrachtet werden, die Modell und Beobachter miteinander verbringen bzw. verbracht haben. Zudem wurde die Wahrnehmung eines Elternteils als Vorbild beim Kind erfragt und als Moderator aufgenommen. In die Analysen eingeschlossen wurden vollständige Mutter-Vater-Kind-Triaden. Im Querschnitt der Fragebogenerhebung waren die Daten von 171 Mädchen und 176 Jungen, in einem 7 Monate darauf folgenden Längsschnitt insgesamt 75 Triaden (davon 38 Mädchen) enthalten. Es zeigte sich ein positiver Zusammenhang zwischen der kindlichen und mütterlichen Ernährung ebenso wie zwischen der kindlichen und väterlichen Ernährung. Die Übereinstimmungen zwischen Mutter und Kind waren größer als zwischen Vater und Kind. Überwiegend bestätigt werden konnten der moderierende Einfluss der Beziehungsqualität und der Vorbildwahrnehmung auf die Zusammenhänge elterlicher und kindlicher gesunder Ernährung und der Einfluss gemeinsam verbrachter Zeit vor allem in Bezug auf Vater-Kind-Zusammenhänge problematischer Ernährung. Der väterliche Einfluss, der sowohl in Studien als auch in präventiven oder therapeutischen Angeboten oft noch vernachlässigt wird und in vorliegender Arbeit besondere bzw. gleichberechtigte Beachtung fand, zeigte sich durch den Einbezug moderierender Variablen verstärkt. Eine Ansprache von Müttern und Vätern gleichermaßen ist somit unbedingtes Ziel bei der Prävention und Therapie kindlicher Adipositas. Auch jenseits des Adipositaskontextes sollten Eltern für die Bedeutung elterlicher Vorbildwirkung sensibilisiert werden, um eine gesunde Ernährungsweise ihrer Kinder zu fördern.
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.
Brasilien ist sowohl politisch als auch wirtschaftlich ein aufstrebendes Land. Seit Jahren regiert in Brasília eine linke Regierung.Trotz Fortschritten im sozialen Bereich gibt es zahlreiche Reformbaustellen. Die gesellschaftliche Spaltung ist tief. Darüber kann auch die anstehende Fußball-WM nicht hinwegtäuschen. Im Gegenteil! Die Brasilianer machten sich unerwartet Luft. Welche Konsequenzen wird Präsidentin Rousseff daraus ziehen und was bedeutet dies für die anderen Linksregierungen in Südamerika?
Tod in den Anden
(2013)
Der Forschungsreisende Francis Hall kam als Soldat nach Südamerika und betätigte sich hier auch als Pflanzensammler, Reiseschriftsteller und Bergsteiger. Er war Freund und Briefpartner Jeremy Benthams und versuchte gemeinsam mit Jean-Baptiste Boussingault den Chimborazo zu besteigen. Der liberale Journalist wurde 1833 in bürgerkriegsähnlichen Unruhen in Ecuador ermordet. Der einzige Brief Halls an Humboldt, in dem er diesen für die Naturerschließung des Landes zu gewinnen versucht, eine Sammlung andiner Pflanzen übersendet und seine Einschätzung zur politischen Lage und Zukunft Südamerikas kundtut, wird hier veröffentlicht und kommentiert.
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.
This thesis deals with Einstein metrics and the Ricci flow on compact mani- folds. We study the second variation of the Einstein-Hilbert functional on Ein- stein metrics. In the first part of the work, we find curvature conditions which ensure the stability of Einstein manifolds with respect to the Einstein-Hilbert functional, i.e. that the second variation of the Einstein-Hilbert functional at the metric is nonpositive in the direction of transverse-traceless tensors. The second part of the work is devoted to the study of the Ricci flow and how its behaviour close to Einstein metrics is influenced by the variational be- haviour of the Einstein-Hilbert functional. We find conditions which imply that Einstein metrics are dynamically stable or unstable with respect to the Ricci flow and we express these conditions in terms of stability properties of the metric with respect to the Einstein-Hilbert functional and properties of the Laplacian spectrum.
Die Arbeit unternimmt den Versuch, Kubricks „2001: Odyssee im Weltraum“ als Metapher für das Ringen mit den Fragen des Lebens unter wesentlicher Betonung der Eigenverantwortung zu lesen. In dieser Hinsicht bestehen erstaunliche Parallelen zum Werk Friedrich Nietzsches. Der Film greift wesentliche Gedanken des deutschen Philosophen auf, indem er seine Kritik zunächst gegen die abendländisch christliche Religion richtet, um sie anschließend konsequent auf die Überhöhung der Wissenschaft, der Vernunft, des Logos auszudehnen. Letztere äußert Kubrick nicht zuletzt durch die Darstellung des scheinbar omnipräsenten und omnipotenten Bordcomputers und die blinde Technologiegläubigkeit, die ihm entgegen gebracht wird. Nachdem die Maschine überwunden ist, tritt der Kern der zunächst vordergründig kulturell-zivilisatorisch wirkenden Entwicklungsgeschichte zu Tage: das Individuum. Der Mensch durchläuft Nietzsches Verwandlungen in Kamel, Löwe und Kind, wodurch er letztlich zu sich selbst findet. Kubricks berühmter Monolith, der gemeinhin als größtes Rätsel des Films gilt, reiht sich dabei ebenso nahtlos in das Gesamtbild ein, wie die nicht weniger Fragen aufwerfende Reise des Protagonisten durch den Lichttunnel oder das schwer verständliche Ende, bei dem sich Bowman mitsamt der Raumkapsel an einem unwirklichen Ort wiederfindet. Nietzsche und Kubrick sind sich in ihrer offenen Vielschichtigkeit so ähnlich, dass die Arbeit weder für den Einen noch für den Anderen in Anspruch nimmt, eine abschließende Deutung vorzulegen. Die Betrachtung versteht sich daher lediglich als Angebot einer kohärenten Lesart des Science-Fiction-Klassikers, deren Gedankengang auch über den für Nietzsche äußerst bedeutsamen Schopenhauer schließlich zu dem deutschen Philosophen führt, der die Schlagworte vom „Übermenschen“ und dem „Willen zur Macht“ prägte.
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.
We introduce the notion of coupling distances on the space of Lévy measures in order to quantify rates of convergence towards a limiting Lévy jump diffusion in terms of its characteristic triplet, in particular in terms of the tail of the Lévy measure. The main result yields an estimate of the Wasserstein-Kantorovich-Rubinstein distance on path space between two Lévy diffusions in terms of the couping distances. We want to apply this to obtain precise rates of convergence for Markov chain approximations and a statistical goodness-of-fit test for low-dimensional conceptual climate models with paleoclimatic data.
Gegenstand dieser Arbeit sind die (Selbst-)Darstellungen von Gründer_innen von Nichtregierungsorganisationen (NGOs) im Bereich Kinder- und Frauenrechte in Tamil Nadu, Südindien. Um diese (Selbst-)Darstellungen angemessen analysieren zu können, wird zuerst eine analytische Herangehensweise entworfen, die davon ausgeht, dass bestehende soziologische Konzepte, die in erster Linie in Auseinandersetzung mit einem spezifischen (west-europäischen) Kontext entstanden sind, nicht unhinterfragt auf andere Kontexte übertragen werden können. Das erschwert die Verwendung von Begrifflichkeiten wie „Zivilgesellschaft“, „Entwicklung“ oder auch der scheinbar klaren Dichotomie von Moderne und Tradition. Eisenstadt machte diese Problematik in der von ihm begonnenen Debatte um „Multiple Modernities“ deutlich. In der vorliegenden Arbeit wird an diese Diskussion mit handlungstheoretischen Argumenten angeknüpft, um auch Akteursperspektiven angemessen analysieren zu können. Nachdem der theoretische Rahmen und die methodische Grundlage der Arbeit erläutert wurden, wird Kontextwissen erarbeitet, um die Analyse der Interviews einzubetten. Es werden Diskurse um Kaste und den Status von Frauen sowie Aspekte der aktuellen politischen Situation Tamil Nadus betrachtet. Die (Selbst-)Darstellungen lassen sich dann anhand der im Titel angedeuteten Dreiteilung aufschlüsseln: Die Gründer_innen setzen sich zum ersten mit der eigenen Rolle auseinander. Sie beschreiben sich als „social worker“ und greifen in den Selbstbeschreibungen zum Teil auf populistische Elemente des politischen Umfeldes zurück. Zum zweiten beschreiben sie die eigene Position gegenüber ihren „Zielgruppen“. Dabei wird deutlich, dass die Beziehungen zwischen NGO und „community“ zwischen Partizipation und Paternalismus schwanken. Zum dritten formulieren sie Zielsetzungen in Abgrenzung zu anderen (lokalen) politischen Akteuren: Sie grenzen sich zum Beispiel von einem ihrem Verständnis nach „westlichen“ Begriff von Entwicklung ab und formulieren demgegenüber „eigene“ Ziele. Sie reflektieren über lokale Kooperationen, z.B. mit politischen Persönlichkeiten, Kastenassoziationen, aber auch über Abgrenzungen oder Zusammenstöße, die sich dabei ergeben. Insgesamt wird deutlich, dass die (Selbst-)Darstellungen der Gründer_innen sich spannungsgeladen und ambivalent auf unterschiedliche Diskurse, Ideen und soziale Praktiken beziehen. Sie lassen sich insbesondere nicht in eine Perspektive von „Entwicklung“ einordnen, welche auf der Dichotomie von Moderne und Tradition aufbaut.
In der vorliegenden Arbeit werden verschiedene Spektrometer für die Analyse von Gasen bzw. Gasgemischen vorgestellt und deren Design, Aufbau, Charakterisierung und Optimierung beschrieben. Das Resultat der Optimierung und Weiterentwicklungen ist ein spektral breitbandiges Cavity-Ring-Down-Spektrometer (CRD-Spektrometer). Ausgangspunkt der hier vorgestellten Arbeit ist ein Spektrometer auf Basis klassischer Absorptionsspektroskopie in einer Multireflexionszelle. Für dieses Spektrometer wurde als Strahlquelle ein Superkontinuumlaser verwendet. Der Vorteil dieses Spektrometers liegt in seiner Kompaktheit. Mit diesem Spektrometer wurden Absorptionsspektren von mehreren Reingasen und einem Gasgemisch über einen Wellenlängenbereich von 1500 nm – 1700 nm aufgenommen. Der qualitative Vergleich mit zu erwartenden Spektren, welche auf der HITRAN-Datenbank basieren, zeigte eine gute Übereinstimmung. Die quantitative Interpretierbarkeit der Daten war jedoch stark eingeschränkt aufgrund des hohen zufälligen und systematischen Fehlers der Messungen. Als Konsequenz aus der als nicht zufriedenstellend bewerteten quantitativen Interpretierbarkeit der Daten wurde eine alternative Messmethode gesucht, welche eine höhere Sensitivität und Genauigkeit ermöglicht. Die Wahl fiel auf die Cavity-Ring-Down-Spektroskopie, eine resonatorgestützte Variante der Absorptionsspektroskopie. Wesentliche Vorteile dieser Technik sind a) die Unabhängigkeit von Leistungsschwankungen der Strahlquelle, b) ein effektiver Absorptionsweg von bis zu mehreren Kilometern, welcher sich unmittelbar auf die Sensitivität der Messungen auswirkt, c) die Ermittlung absoluter Absorberkonzentrationen, ohne die Notwendigkeit einer Kalibrierung oder den Vergleich mit einer Referenzzelle und d) die Vernachlässigbarkeit von Absorptionen außerhalb des Resonators. Als notwendiger Zwischenschritt auf dem Weg zu einem breitbandigen CRD-Spektrometer wurde zunächst ein monochromatisches CRD-Spektrometer designt, aufgebaut und charakterisiert. Für die effektive Einkopplung von Strahlungsenergie in einen Resonator ist die Anpassung der Strahlparameter an die Mode des Resonators notwendig. Voraussetzung dieser Anpassung ist die Kenntnis der Strahlparameter, welche experimentell ermittelt wurden. Im Laufe des Aufbaus des Spektrometers ergab sich, dass trotz der Modenanpassung die Einkopplung der Strahlungsenergie in den Resonator gestört wurde. Daraufhin wurden systematisch mögliche Ursachen dieser Störung untersucht und das Spektrometer optimiert. Mit diesem optimierten Spektrometer wurden Spektren gemessen, welche sowohl qualitativ als auch quantitativ gut mit den zu erwartenden Spektren übereinstimmen. Als Nachweisgrenze dieses Spektrometers wurde ein Wert für den Absorptionskoeffizienten alpha von 10^-8 cm-1 bestimmt. Mit dem monochromatischen CRD-Spektrometer war es zudem möglich, isotopenspezifische Messungen durchzuführen. Für das breitbandige Spektrometer wurde als Strahlquelle eine ASE-Diode (amplified spontaneous emission) verwendet. Dabei handelt es sich um eine inkohärente Strahlquelle. Mittels Messungen nach dem Prinzip der Cavity-Enhanced-Absorptionsspektroskopie wurde die generelle Funktionalität des resonatorgestützten Spektrometers überprüft. Anschließend wurden die wellenlängenabhängigen Abklingsignale des leeren und des mit einem CO2-Luft-Gemisch gefüllten Resonators gemessen und ebenfalls mit den zu erwartenden Spektren verglichen. Qualitativ stimmen die experimentellen Spektren gut mit den zu erwartenden Spektren überein. Für die quantitative Interpretation der Daten wurde ein spezieller Algorithmus entwickelt, der die spektrale Auflösung des Systems berücksichtigt. Mit dem vorgestellten Spektrometer ist so die qualitative und quantitative Interpretation der Spektren möglich. Die Nachweisgrenze des breitbandigen Cavity-Ring-Down-Spektrometers wurde zu einem Wert von alpha = 8x10^-7 cm-1 bestimmt. Der systematischen und der zufällige Fehler der Messungen lagen bei Werten von ca. 1%. Bei diesem Spektrometer handelt es sich um einen Prototyp. Mittels Optimierung des Systems lassen sich sowohl der Wert der Nachweisgrenze als auch die Fehler der Messungen verbessern.
This book deals with the inner life of the capitalist firm. There we find numerous conflicts, the most important of which concerns the individual employment relationship which is understood as a principal-agent problem between the manager, the principal, who issues orders that are to be followed by the employee, the agent. Whereas economic theory traditionally analyses this relationship from a (normative) perspective of the firm in order to support the manager in finding ways to influence the behavior of the employees, such that the latter – ideally – act on behalf of their superior, this book takes a neutral stance. It focusses on explaining individual behavioral patterns and the resulting interactions between the actors in the firm by taking sociological, institutional, and above all, psychological research into consideration. In doing so, insights are gained which challenge many assertions economists take for granted.
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.
The phenolic compounds as food components represent the largest group of secondary metabolites in plant foods. The phenolic compounds, e.g. chlorogenic acid (CQA), are susceptible to oxidation by enzymes specially, polyphenol oxidase (PPO) and at alkaline conditions. Both enzymatic and non-enzymatic oxidations occur in the presence of oxygen and produce quinone, which normally further react with other quinone to produce colored compounds (dimers), as well as is capable of undergoing a nucleophilic addition to proteins. The interactions of proteins with the phenolic compounds have received considerable attention in the recent years where, plant phenolic compounds have drawn increasing attention due to their antioxidant properties and their noticeable effects in the prevention of various oxidative stress associated diseases. Green coffee beans are one of the richest sources of chlorogenic acids. Therefore, a green coffee extract would provide an eligible food relevant source for phenolic compounds for modification of proteins. The interaction between 5-CQA and amino acid lysine showed decrease in both free CQA and amino acid groups and only a slight effect on the antioxidative capacity depending on the reaction time was found. Furthermore, this interaction showed a large number of intermediary substances of low intensities. The reaction of lysine with 5-CQA in a model system initially leads to formation of 3-CQA and 4-CQA (both are isomers of 5-CQA), oxidation giving rise to the formation of a dimer which subsequently forms an adduct with lysine to finally result in a benzacridine derivative as reported and confirmed with the aid of HPLC coupled with ESI-MSn. The benzacridine derivative containing a trihydroxy structural element, was found to be yellow, being very reactive with oxygen yielding semiquinone and quinone type of products with characteristic green colors. Finally, the optimal conditions for this interaction as assessed by both the loss of CQA and free amino groups of lysine can be given at pH 7 and 25°C, the interaction increasing with incubation time and depending also on the amount of tyrosinase present. Green coffee bean has a higher diversity and content of phenolics, where besides the CQA isomers and their esters, other conjugates like feruloylquinic acids were also identified, thus documenting differences in phenolic profiles for the two coffee types (Coffea arabica and Coffea robusta). Coffee proteins are modified by interactions with phenolic compounds during the extraction, where those from C. arabica are more susceptible to these interactions compared to C. robusta, and the polyphenol oxidase activity seems to be a crucial factor for the formation of these addition products. Moreover, In-gel digestion combined with MALDI-TOF-MS revealed that the most reactive and susceptible protein fractions to covalent reactions are the α-chains of the 11S storage protein. Thus, based on these results and those supplied by other research groups, a tentative list of possible adduct structures was derived. The diversity of the different CQA derivatives present in green coffee beans complicates the series of reactions occurring, providing a broad palette of reaction products. These interactions influence the properties of protein, where they exposed changes in the solubility and hydrophobicity of proteins compared to faba bean proteins (as control). Modification of milk whey protein products (primarily b-lactoglobulin) with coffee specific phenolics and commercial CQA under enzymatic and alkaline conditions seems to be affecting their chemical, structural and functional properties, where both modifications led to reduced free amino-,thiol groups and tryptophan content. We propose that the disulfide-thiol exchange in the C-terminus of b-lactoglobulin may be initiated by the redox conditions provided in the presence of CQA. The protein structure b-lactoglobulin thereupon becomes more disordered as simulated by molecular dynamic calculation. This unfolding process may additionally be supported by the reaction of the CQA at the proposed sites of modification of -amino groups of lysine (K77, K91, K138, K47) and the thiol group of cysteine (C121). These covalent modifications also decreased the solubility and hydrophobicity of b-lactoglobulin, moreover they provide modified protein samples with a high antioxidative power, thermally more stable as reflected by a higher Td, require less amount of energy to unfold and when emulsified with lutein esters, exhibit their higher stability against UV light. The MALDI-TOF and SDS-PAGE results revealed that proteins treated at alkaline conditions were more strongly modified than those treated under enzymatic conditions. Finally, the results showed a slight change in emulsifying properties of modified proteins.
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.
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.
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 main intention of the PhD project was to create a varve chronology for the Suigetsu Varves 2006' (SG06) composite profile from Lake Suigetsu (Japan) by thin section microscopy. The chronology was not only to provide an age-scale for the various palaeo-environmental proxies analysed within the SG06 project, but also and foremost to contribute, in combination with the SG06 14C chronology, to the international atmospheric radiocarbon calibration curve (IntCal). The SG06 14C data are based on terrestrial leaf fossils and therefore record atmospheric 14C values directly, avoiding the corrections necessary for the reservoir ages of the marine datasets, which are currently used beyond the tree-ring limit in the IntCal09 dataset (Reimer et al., 2009). The SG06 project is a follow up of the SG93 project (Kitagawa & van der Plicht, 2000), which aimed to produce an atmospheric calibration dataset, too, but suffered from incomplete core recovery and varve count uncertainties. For the SG06 project the complete Lake Suigetsu sediment sequence was recovered continuously, leaving the task to produce an improved varve count. Varve counting was carried out using a dual method approach utilizing thin section microscopy and micro X-Ray Fluorescence (µXRF). The latter was carried out by Dr. Michael Marshall in cooperation with the PhD candidate. The varve count covers 19 m of composite core, which corresponds to the time frame from ≈10 to ≈40 kyr BP. The count result showed that seasonal layers did not form in every year. Hence, the varve counts from either method were incomplete. This rather common problem in varve counting is usually solved by manual varve interpolation. But manual interpolation often suffers from subjectivity. Furthermore, sedimentation rate estimates (which are the basis for interpolation) are generally derived from neighbouring, well varved intervals. This assumes that the sedimentation rates in neighbouring intervals are identical to those in the incompletely varved section, which is not necessarily true. To overcome these problems a novel interpolation method was devised. It is computer based and automated (i.e. avoids subjectivity and ensures reproducibility) and derives the sedimentation rate estimate directly from the incompletely varved interval by statistically analysing distances between successive seasonal layers. Therefore, the interpolation approach is also suitable for sediments which do not contain well varved intervals. Another benefit of the novel method is that it provides objective interpolation error estimates. Interpolation results from the two counting methods were combined and the resulting chronology compared to the 14C chronology from Lake Suigetsu, calibrated with the tree-ring derived section of IntCal09 (which is considered accurate). The varve and 14C chronology showed a high degree of similarity, demonstrating that the novel interpolation method produces reliable results. In order to constrain the uncertainties of the varve chronology, especially the cumulative error estimates, U-Th dated speleothem data were used by linking the low frequency 14C signal of Lake Suigetsu and the speleothems, increasing the accuracy and precision of the Suigetsu calibration dataset. The resulting chronology also represents the age-scale for the various palaeo-environmental proxies analysed in the SG06 project. One proxy analysed within the PhD project was the distribution of event layers, which are often representatives of past floods or earthquakes. A detailed microfacies analysis revealed three different types of event layers, two of which are described here for the first time for the Suigetsu sediment. The types are: matrix supported layers produced as result of subaqueous slope failures, turbidites produced as result of landslides and turbidites produced as result of flood events. The former two are likely to have been triggered by earthquakes. The vast majority of event layers was related to floods (362 out of 369), which allowed the construction of a respective chronology for the last 40 kyr. Flood frequencies were highly variable, reaching their greatest values during the global sea level low-stand of the Glacial, their lowest values during Heinrich Event 1. Typhoons affecting the region represent the most likely control on the flood frequency, especially during the Glacial. However, also local, non-climatic controls are suggested by the data. In summary, the work presented here expands and revises knowledge on the Lake Suigetsu sediment and enabls the construction of a far more precise varve chronology. The 14C calibration dataset is the first such derived from lacustrine sediments to be included into the (next) IntCal dataset. References: Kitagawa & van der Plicht, 2000, Radiocarbon, Vol 42(3), 370-381 Reimer et al., 2009, Radiocarbon, Vol 51(4), 1111-1150
Der Aufsatz rekonstruiert Daniel Heinsius’ Verachtung der Philologie, wie sie in seinen „Orationes” zum Ausdruck kommt. Die These lautet, dass diese Verachtung in Heinsius’ neuplatonischer Poetik mit ihrer Sakralisierung der Dichtung begründet ist. In seinem Kommentar zur aristotelischen „Poetik“, der „Constitutio tragoediae“, ordnet Heinsius das technische Wissen der aristotelischen „Poetik“ der neuplatonischen Inspirationstheorie unter. Dadurch transformiert er den traditionellen, historisch-philologischen Kommentar in eine neue Form des technischen Handbuchs, wie es die „Constitutio tragoediae“ darstellt.
In der Diskussion über Freiheit und Verantwortung vertritt die Hirnforschung die These, dass wir determiniert sind und unser Gehirn es ist, das denkt und entscheidet. Aus diesem Grunde könne uns für unsere Entscheidungen und Handlungen auch keine Verantwortung zugewiesen werden. Die Philosophie versucht in dieser Diskussion zu klären, ob wir trotz Determiniertheit für unsere Entscheidungen und Urteile verantwortlich sind oder ob Vereinbarkeit von Freiheit und Determinismus grundsätzlich nicht möglich ist. Diese Fragen stellt diese Untersuchung über Freiheit und Verantwortung nicht. In dieser Untersuchung wird ein gewisses Maß an Freiheit vorausgesetzt, weil diese Annahme der erste Schritt für unsere Freiheit ist. In dieser Arbeit geht es um die Verbindung von Freiheit und Verantwortung und was diese Verbindung in unserem Menschsein und Miteinander bedeutet. Ziel ist es, zu zeigen, dass wir uns zusätzliche Freiheit aneignen können, dass Bildung für unsere Freiheit nötig und dass Freiheit ohne Verantwortung nicht möglich ist. Die Untersuchung schließt sich Peter Bieris Thesen an, dass Aneignung von Freiheit und Bildung, die weder als Schul- noch als Ausbildung zu verstehen ist, möglich und nötig sind, um verantwortlich entscheiden und handeln zu können, lehnt jedoch Peter Bieris These ab, dass bedingte Freiheit Voraussetzung für unsere Freiheit ist. Zudem geht diese Arbeit über Peter Bieri hinaus, indem sie eine Lösungsmöglichkeit für unsere Freiheit und der damit verbundenen Verantwortlichkeit anbietet. Als Lösung wird eine Bildung vorgeschlagen, die uns die Verbundenheit mit den anderen und die Abhängigkeit von den anderen zeigt und die die Rechte und Bedürfnisse der anderen ebenso anerkennen lässt wie unsere eigenen. Es ist eine Bildung, die nicht nur Wissen, sondern auch bestimmte rationale und emotionale Kompetenzen beinhaltet. Es ist eine Bildung, die als lern- und lehrbar angesehen wird. Um diese Bildung als eine Notwendigkeit für unsere Freiheit und Verantwortlichkeit uns und den anderen gegenüber vermitteln zu können, ist es wichtig, uns in unserem Wesen verstehen. Deshalb werden in dieser Arbeit Faktoren dargestellt, die auf uns wirken und die uns als Menschen ausmachen. Es sind Faktoren, die auf unsere Freiheit und Verantwortung Einfluss nehmen, indem sie unsere Entscheidungen, unser Urteilsvermögen und in diesem Sinne auch unsere Handlungen ermöglichen oder einschränken. Durch die Darstellung dieser Faktoren werden wir auf unsere Möglichkeiten hingewiesen, die uns unser Leben in Selbstverantwortung und in Verantwortlichkeit den anderen gegenüber gestalten lassen. In dieser Untersuchung wird gezeigt, dass Freiheit ohne Verantwortung nicht möglich ist und es wird gezeigt, dass wir, wenn wir unsere Verantwortung abgeben, unsere Freiheit verlieren.
Water management and environmental protection is vulnerable to extreme low flows during streamflow droughts. During the last decades, in most rivers of Central Europe summer runoff and low flows have decreased. Discharge projections agree that future decrease in runoff is likely for catchments in Brandenburg, Germany. Depending on the first-order controls on low flows, different adaption measures are expected to be appropriate. Small catchments were analyzed because they are expected to be more vulnerable to a changing climate than larger rivers. They are mainly headwater catchments with smaller ground water storage. Local characteristics are more important at this scale and can increase vulnerability. This thesis mutually evaluates potential adaption measures to sustain minimum runoff in small catchments of Brandenburg, Germany, and similarities of these catchments regarding low flows. The following guiding questions are addressed: (i) Which first-order controls on low flows and related time scales exist? (ii) Which are the differences between small catchments regarding low flow vulnerability? (iii) Which adaption measures to sustain minimum runoff in small catchments of Brandenburg are appropriate considering regional low flow patterns? Potential adaption measures to sustain minimum runoff during periods of low flows can be classified into three categories: (i) increase of groundwater recharge and subsequent baseflow by land use change, land management and artificial ground water recharge, (ii) increase of water storage with regulated outflow by reservoirs, lakes and wetland water management and (iii) regional low flow patterns have to be considered during planning of measures with multiple purposes (urban water management, waste water recycling and inter-basin water transfer). The question remained whether water management of areas with shallow groundwater tables can efficiently sustain minimum runoff. Exemplary, water management scenarios of a ditch irrigated area were evaluated using the model Hydrus-2D. Increasing antecedent water levels and stopping ditch irrigation during periods of low flows increased fluxes from the pasture to the stream, but storage was depleted faster during the summer months due to higher evapotranspiration. Fluxes from this approx. 1 km long pasture with an area of approx. 13 ha ranged from 0.3 to 0.7 l\s depending on scenario. This demonstrates that numerous of such small decentralized measures are necessary to sustain minimum runoff in meso-scale catchments. Differences in the low flow risk of catchments and meteorological low flow predictors were analyzed. A principal component analysis was applied on daily discharge of 37 catchments between 1991 and 2006. Flows decreased more in Southeast Brandenburg according to meteorological forcing. Low flow risk was highest in a region east of Berlin because of intersection of a more continental climate and the specific geohydrology. In these catchments, flows decreased faster during summer and the low flow period was prolonged. A non-linear support vector machine regression was applied to iteratively select meteorological predictors for annual 30-day minimum runoff in 16 catchments between 1965 and 2006. The potential evapotranspiration sum of the previous 48 months was the most important predictor (r²=0.28). The potential evapotranspiration of the previous 3 months and the precipitation of the previous 3 months and last year increased model performance (r²=0.49, including all four predictors). Model performance was higher for catchments with low yield and more damped runoff. In catchments with high low flow risk, explanatory power of long term potential evapotranspiration was high. Catchments with a high low flow risk as well as catchments with a considerable decrease in flows in southeast Brandenburg have the highest demand for adaption. Measures increasing groundwater recharge are to be preferred. Catchments with high low flow risk showed relatively deep and decreasing groundwater heads allowing increased groundwater recharge at recharge areas with higher altitude away from the streams. Low flows are expected to stay low or decrease even further because long term potential evapotranspiration was the most important low flow predictor and is projected to increase during climate change. Differences in low flow risk and runoff dynamics between catchments have to be considered for management and planning of measures which do not only have the task to sustain minimum runoff.
The life of microorganisms is characterized by two main tasks, rapid growth under conditions permitting growth and survival under stressful conditions. The environments, in which microorganisms dwell, vary in space and time. The microorganisms innovate diverse strategies to readily adapt to the regularly fluctuating environments. Phenotypic heterogeneity is one such strategy, where an isogenic population splits into subpopulations that respond differently under identical environments. Bacterial persistence is a prime example of such phenotypic heterogeneity, whereby a population survives under an antibiotic attack, by keeping a fraction of population in a drug tolerant state, the persister state. Specifically, persister cells grow more slowly than normal cells under growth conditions, but survive longer under stress conditions such as the antibiotic administrations. Bacterial persistence is identified experimentally by examining the population survival upon an antibiotic treatment and the population resuscitation in a growth medium. The underlying population dynamics is explained with a two state model for reversible phenotype switching in a cell within the population. We study this existing model with a new theoretical approach and present analytical expressions for the time scale observed in population growth and resuscitation, that can be easily used to extract underlying model parameters of bacterial persistence. In addition, we recapitulate previously known results on the evolution of such structured population under periodically fluctuating environment using our simple approximation method. Using our analysis, we determine model parameters for Staphylococcus aureus population under several antibiotics and interpret the outcome of cross-drug treatment. Next, we consider the expansion of a population exhibiting phenotype switching in a spatially structured environment consisting of two growth permitting patches separated by an antibiotic patch. The dynamic interplay of growth, death and migration of cells in different patches leads to distinct regimes in population propagation speed as a function of migration rate. We map out the region in parameter space of phenotype switching and migration rate to observe the condition under which persistence is beneficial. Furthermore, we present an extended model that allows mutation from the two phenotypic states to a resistant state. We find that the presence of persister cells may enhance the probability of resistant mutation in a population. Using this model, we explain the experimental results showing the emergence of antibiotic resistance in a Staphylococcus aureus population upon tobramycin treatment. In summary, we identify several roles of bacterial persistence, such as help in spatial expansion, development of multidrug tolerance and emergence of antibiotic resistance. Our study provides a theoretical perspective on the dynamics of bacterial persistence in different environmental conditions. These results can be utilized to design further experiments, and to develop novel strategies to eradicate persistent infections.
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.
Die Arbeit beleuchtet die Beziehungen zwischen der DDR und der Volksrepublik China in den Jahren 1978 bis 1990. Dabei werden sowohl die innen-, wie auch die außenpolitischen Bedingungen dieser Beziehungen in der DDR und China beleuchtet. Besonderes Augenmerk wird auch auf die Sowjetunion gelegt. Die Beziehungen Moskaus gegenüber Beijing und Ostberlin werden dargestellt und mit den daraus resultierenden Folgen für die DDR-Führung in Bezug gesetzt.
The fragmentation of natural habitat caused by anthropogenic land use changes is one of the main drivers of the current rapid loss of biodiversity. In face of this threat, ecological research needs to provide predictions of communities' responses to fragmentation as a prerequisite for the effective mitigation of further biodiversity loss. However, predictions of communities' responses to fragmentation require a thorough understanding of ecological processes, such as species dispersal and persistence. Therefore, this thesis seeks an improved understanding of community dynamics in fragmented landscapes. In order to approach this overall aim, I identified key questions on the response of plant diversity and plant functional traits to variations in species' dispersal capability, habitat fragmentation and local environmental conditions. All questions were addressed using spatially explicit simulations or statistical models. In chapter 2, I addressed scale-dependent relationships between dispersal capability and species diversity using a grid-based neutral model. I found that the ratio of survey area to landscape size is an important determinant of scale-dependent dispersal-diversity relationships. With small ratios, the model predicted increasing dispersal-diversity relationships, while decreasing dispersal-diversity relationships emerged, when the ratio approached one, i.e. when the survey area approached the landscape size. For intermediate ratios, I found a U-shaped pattern that has not been reported before. With this study, I unified and extended previous work on dispersal-diversity relationships. In chapter 3, I assessed the type of regional plant community dynamics for the study area in the Southern Judean Lowlands (SJL). For this purpose, I parameterised a multi-species incidence-function model (IFM) with vegetation data using approximate Bayesian computation (ABC). I found that the type of regional plant community dynamics in the SJL is best characterized as a set of isolated “island communities” with very low connectivity between local communities. Model predictions indicated a significant extinction debt with 33% - 60% of all species going extinct within 1000 years. In general, this study introduces a novel approach for combining a spatially explicit simulation model with field data from species-rich communities. In chapter 4, I first analysed, if plant functional traits in the SJL indicate trait convergence by habitat filtering and trait divergence by interspecific competition, as predicted by community assembly theory. Second, I assessed the interactive effects of fragmentation and the south-north precipitation gradient in the SJL on community-mean plant traits. I found clear evidence for trait convergence, but the evidence for trait divergence fundamentally depended on the chosen null-model. All community-mean traits were significantly associated with the precipitation gradient in the SJL. The trait associations with fragmentation indices (patch size and connectivity) were generally weaker, but statistically significant for all traits. Specific leaf area (SLA) and plant height were consistently associated with fragmentation indices along the precipitation gradient. In contrast, seed mass and seed number were interactively influenced by fragmentation and precipitation. In general, this study provides the first analysis of the interactive effects of climate and fragmentation on plant functional traits. Overall, I conclude that the spatially explicit perspective adopted in this thesis is crucial for a thorough understanding of plant community dynamics in fragmented landscapes. The finding of contrasting responses of local diversity to variations in dispersal capability stresses the importance of considering the diversity and composition of the metacommunity, prior to implementing conservation measures that aim at increased habitat connectivity. The model predictions derived with the IFM highlight the importance of additional natural habitat for the mitigation of future species extinctions. In general, the approach of combining a spatially explicit IFM with extensive species occupancy data provides a novel and promising tool to assess the consequences of different management scenarios. The analysis of plant functional traits in the SJL points to important knowledge gaps in community assembly theory with respect to the simultaneous consequences of habitat filtering and competition. In particular, it demonstrates the importance of investigating the synergistic consequences of fragmentation, climate change and land use change on plant communities. I suggest that the integration of plant functional traits and of species interactions into spatially explicit, dynamic simulation models offers a promising approach, which will further improve our understanding of plant communities and our ability to predict their dynamics in fragmented and changing landscapes.
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.
St. Petersburg – wie es isst
(2013)
Das Eigene und das Fremde
(2013)