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Recent estimates have confirmed that inland waters emit a considerable amount of CH4 and CO2 to the atmosphere at the regional and global scale. But these estimates are based on extrapolated measured data and lack of data from inland waters in arid and semi-arid regions and carbon sources from wastewater treatment plants (WWTPs) as well insufficient resolution of the spatiotemporal variability of these emissions.
Through this study, we analyzed monthly hydrological, meteorological and water quality data from three irrigation and drinking water reservoirs in the lower Jordan River basin and estimated the atmospheric emission rates of CO2. We investigated the effect of WWTPs on surrounding aquatic systems in term of CH4 and CO2 emission by presenting seasonally resolved data for dissolved concentrations of both gases in the effluents and in the receiving streams at nine WWTPs in Germany.
We investigated spatiotemporal variability of CH4 and CO2 emission from aquatic ecosystems by using of simple low-cost tools for measuring CO2 flux and bubble release rate from freshwater systems. Our estimates showed that reservoirs in semi-arid regions are oversaturated with CO2 and acted as net sources to the atmosphere. The magnitude of observed fluxes at the three water reservoirs in Jordan is comparable to those from tropical reservoirs (3.3 g CO2 m-2 d-1). The CO2 emission rate from these reservoirs is linked to changes of water surface area, which is the result of water management practices. WWTPs have been shown to discharge a considerable amount of CH4 (30.9±40.7 kg yr-1) and CO2 (0.06±0.05 Gg yr-1) to their surrounding streams, and emission rates of CH4 and CO2 from these streams are significantly enhanced by effluents of WWTPs up to 1.2 and 8.6 times, respectively.
Our results showed that both diffusive flux and bubble release rate varied in time and space, and both of emission pathways should be included and variability should be resolved adequately in further sampling and measuring strategies. We conclude that future emission measurements and estimates from inland waters may consider water management practices, carbon sources from WWTPs as well spatial and temporal variability of emission.
Die laserinduzierte Plasmaspektroskopie (”Laser Induced Breakdown Spectroscopy”, im Folgenden auch ”LIBS” genannt) stellt eine schnelle und berührungslose Messmethode zur Elementanalyse von festen, flüssigen oder gasförmigen Stoffen unter normalen Umgebungsbedingungen ohne besondere Probenvorbereitung dar. Dazu wird ein gepulster Laser, dessen Intensität einen bestimmten Grenzwert überschreiten muss, auf eine Probe fokussiert. Das dort bestrahlte Material verdampft schlagartig und es bildet sich bei einer Temperatur von rund 10000 K ein Plasma aus. Die angeregten Atome und Ionen im Plasma strahlen bei der Rückkehr in energetisch niedrigere Zustände ein charakteristisches optisches Emissionsspektrum ab, welches über eine schnelle spektroskopische Analyse die Elementzusammensetzung des untersuchten Materials liefert. LIBS bietet in diesem Fall auch die Möglichkeit, ein unkompliziertes und bildgebendes Messverfahren aufzubauen, indem Elementverteilungen auf einer topographischen Oberfläche analysiert werden, um beispielsweise Materialübergänge, Einschlüsse oder Verschmutzungen sicher zu detektieren. Bei unebenen Oberflächen wird eine ständige Anpassung des Laserfokus an die Probenkontur benötigt, da die notwendige Intensität zur Erzeugung des Plasmas nur im Fokus aufgebracht werden kann. Als Grundlage dafür dient ein neu entwickelter Fokussieralgorithmus, der ohne jegliche Zusatzgeräte auskommt, und die Reproduzierbarkeit von LIBS-Messungen deutlich steigern kann, da die Messungen kontrolliert im Fokus stattfinden. Durch ihn ergeben sich neue Möglichkeiten des sogenannten „Element-Mappings", dem Erzeugen von Elementlandkarten, welche die Elementverteilungen in Falschfarben grafisch darstellen. Dabei ist das System nun nicht mehr auf eine ebene Oberfläche angewiesen, sondern kann beliebige Strukturen, auch mit scharfen Kanten und Löchern, sicher vermessen. Als Ergebnis erhält man ein flächiges Höhenprofil, welches zusätzlich die Elementinformationen für jeden Messpunkt beinhaltet. Dies erleichtert es dem Benutzer, gezielt Punkte von Interesse schnell wiederzufinden und zu analysieren. Die vorliegende Arbeit beschreibt die Entwicklung eines bildgebenden Low-Power-LIBSSystems mit niedriger Pulsenergie und hoher Pulsrate, welches sich mit dem dazugehörigen
Fokussieralgorithmus automatisiert an unebene Probenoberflächen anpassen kann. Als Ergebnisse werden die Analysen von ausgewählten metallhaltigen, geologischen, organischen und archäologischen Proben bzw. Fundstücken gezeigt.
Agriculture covers one third of the world land area and has become a major source of water pollution due to its heavy reliance on chemical inputs, namely fertilisers and pesticides. Several thousands of tonnes of these chemicals are applied worldwide annually and partly reach freshwaters. Despite their widespread use and relatively unspecific modes of action, fungicides are the least studied group of pesticides. It remains unclear whether the taxonomic groups used in pesticide risk assessment are protective for non-target freshwater fungi. Fungi and bacteria are the main microbial decomposers converting allochthonous organic matter (litter) into a more nutritious food resource for leaf-shredding macroinvertebrates. This process of litter decomposition (LD) is central for aquatic ecosystem because it fuels local and downstream food webs with energy and nutrients. Effects of fungicides on decomposer communities and LD have been mainly analysed under laboratory conditions with limited representation of the multiple factors that may moderate effects in the field.
In this thesis a field study was conducted in a German vineyard area to characterise recurrent episodic exposure to fungicides in agricultural streams (chapter 2) and its effects on decomposer communities and LD (chapter 3). Additionally, potential interaction effects of nutrient enrichment and fungicides on decomposer communities and LD were analysed in a mesocosm experiment (chapter 4).
In the field study event-driven water sampling (EDS) and passive sampling with EmporeTM styrene-divinylbenzene reverse phase sulfonated disks (SDB disks) were used to assess exposure to 15 fungicides and 4 insecticides. A total of 17 streams were monitored during 4 rainfall events within the local application period of fungicides in 2012. EDS exceeded the time-weighted average concentrations provided by the SDB disks by a factor of 3, though high variability among compounds was observed. Most compounds were detected in more than half of the sites and mean and maximum peak (EDS) concentrations were under 1 and 3 µg/l, respectively. Besides, SDB disk-sampling rates and a free-software solution to derive sampling rates under time-variable exposure were provided.
Several biotic endpoints related to decomposers and LD were measured in the same sampling sites as the fungicide monitoring, coinciding with the major litter input period. Our results suggest that polar organic fungicides in streams change the structure of the fungal community. Causality of this finding was supported by a subsequent microcosm experiment. Whether other effects observed in the field study, such as reduced fungal biomass, increased bacterial density or reduced microbial LD can be attributed to fungicides remains speculative and requires further investigation. By contrast, neither the invertebrate LD nor in-situ measured gammarid feeding rates correlated with water-borne fungicide toxicity, but both were negatively associated with sediment copper concentrations. The mesocosm experiment showed that fungicides and nutrients affect microbial decomposers differently and that they can alter community structure, though longer experiments are needed to determine whether these changes may propagate to invertebrate communities and LD. Overall, further studies should include representative field surveys in terms of fungicide pollution and physical, chemical and biological conditions. This should be combined with experiments under controlled conditions to test for the causality of field observations.
This study had two main aims. The first one was to investigate the quality of lesson plans. Two important features of lesson plans were used as a basis to determine the quality of lesson plans. These are adaptability to preconditions and cognitive activation of students. The former refers to how the planning teacher considers the diversity of students pre-existing knowledge and skills. The latter refers to how the planning teacher sequences deep learning tasks and laboratory activities to promote the cognitive activation of students.
The second aim of the study was to explore teachers thinking about and explanation of externally generated feedback data on their students’ performance. The emphasis here was to understand how the teachers anticipate planning differentiated lessons to accommodate the variations in students learning outcomes revealed by the feedback data.
The study followed a qualitative approach with multiple sources of data. Concept maps, questionnaires, an online lesson planning tool, standardized tests, and semi-structured interviews were the main data collection instruments used in the study. Participants of this study were four physics teachers teaching different grade levels. For the purpose of generating feedback for the participant teachers, a test was administered to 215 students. Teachers were asked to plan five lessons for their ongoing practices. The analysis showed that the planned lessons were not adapted to the diversity in students pre-existing knowledge and skills. The analysis also indicated that the lessons planned had limitations with regard to cognitive activation of students. The analysis of the interview data also revealed that the participant teachers do not normally consider differentiating lessons to accommodate the differences in students learning, and place less emphasis on the cognitive activation of students. The analysis of the planned lessons showed a variation in teachers approach in integrating laboratory activities in the sequence of the lessons ranging from a complete absence through a demonstrative to an investigative approach. Moreover, the findings from the interviews indicated differences between the participant teachers espoused theory (i.e. what they said during interview) and their theory- in –use (i.e. what is evident from the planned lessons). The analysis of the interview data demonstrated that teachers did not interpret the data, identify learning needs, draw meaningful information from the data for adapting (or differentiating) instruction. They attributed their students’ poor performance to task difficulty, students’ ability, students’ motivation and interest. The teachers attempted to use the item level and subscale data only to compare the relative position of their class with the reference group. However, they did not read beyond the data, like identifying students learning needs and planning for differentiated instruction based on individual student’s performance.
In jüngerer Vergangenheit erlebt der zumeist auf Michel Foucault zurückgeführte Begriff des 'Dispositivs' – ähnlich wie zuvor der des 'Diskurses' – eine regelrechte Konjunktur in den Geistes-, Sozial- und Kulturwissenschaften. Seine Verwendung weist jedoch eine Reihe von Verkürzungen und Entstellungen auf; so werden damit recht pauschal meist bloß die architekturalen und/oder räumlichen Umstände bzw. Kontexte sozialer, medialer oder anderer Situationen bezeichnet, ohne die für Foucault so wichtigen Fragen nach Wissen, Macht und Subjektivität zu beachten. So gerät der Begriff in Gefahr, seine theoretische und analytische Potenz einzubüßen.
In „Im Dispositiv. Macht, Medium, Wissen“ legt die Autorin daher in einem ersten Schritt eine Präzisierung des Dispositivbegriffs vor, der den zugrundeliegenden Theoriehorizont Foucaults systematisch miteinbezieht. Dazu werden zunächst diskurstheoretische Grundlagen erläutert und anschließend deren strukturelle Analogien zu den machtanalytischen Befunden Foucaults mit Hilfe einer neuen Terminologie sichtbar gemacht.
Vor allem in den Medienwissenschaften ist der Begriff des Dispositivs prominent, um die gesellschaftliche Einbettung von Einzelmedien zu pointieren. Jedoch fällt auf, dass der dort in weiten Teilen vertretene Ansatz, Medien als Dispositive zu verstehen, den Blick auf medienspezifische Eigenlogiken verstellt. In einem zweiten Schritt weist die Autorin daher die strukturellen Analogien von Medialität, Wissen und Macht auf und kommt so zu einem integrativen Dispositivkonzept, das die drei Sphären als dynamisch miteinander verknüpfte, interdependente und reziproke Felder von Kultur modelliert.
This thesis presents the analysis of gamebased touristic applications. In tourism, actions can only be motivated intrinsic. Thus, this thesis at first researches specific intrinsic motivation concepts. It shows how gamebased motivation can be produced on purpose and answers the question whether gamebased motivation can be transferred to non-gamebased applications.
Using these results, different touristic applications have been developed and evaluated.
All applications aimed to add value to the touristic experience. The applications are sorted by their mobility. There are completely mobile, completely stationary and hybrid systems in this work. There are different ways to add value which are presented in this work: Gamebased exploration, knowledge transfer and social interaction between tourists.
Finally, an authoring tool for gamebased touristic tours on smartphones is presented.
The largest population of the anadromous Allis shad (A. alosa) of the 19th century was found in River Rhine and has to be considered extinct today. To facilitate the return of A. alosa into River Rhine an EU LIFE-project was initiated in 2007. The overall objective of this thesis was to assist aquaculture and stocking-measures at River Rhine, as well as to support restoration and conservation of populations of Allis shad in Europe.
By culturing the free-swimming nematode T. aceti in a solution of cider vinegar we developed a cost-effective live food organism for the larviculture of fish. As indicated by experiments with C. maraena, T. aceti cannot be regarded as an alternative to Artemia nauplii. However it has to be considered a suitable supplemental feed in the early rearing of C. maraena by providing essential fatty acids, thereby optimizing growth.
Also mass-marking practices with Oxytetracycline, as they are applied in the restocking of Allis shad have been evaluated. In experiments with D. rerio we demonstrated that water hardness can detrimentally affect mortality during marking and has to be considered crucial in the development of marking protocols for freshwater fish.
In order to get independent from wild spawners an ex-situ Broodstock-facility for Allis shad was established in 2011. Upon examination of two complete year classes of this broodstock, we found a high prevalence of various malformations, which could be traced back to distinct cysts developing one month post hatch. Despite applying a variety of clinical tests we could not identify any infectious agents causing these malformations. The observed malformations are probably a consequence of suboptimal feeding practices or the properties of the physio-chemical rearing environment.
The decline of stocks of A. alosa in Europe has been largely explained with the increase of river temperatures as a consequence of global warming. By investigating the temperature physiology of larval Allis shad we demonstrated that A. alosa ranges among the most thermo-tolerant species in Europe and that correlations between rising temperatures and the disappearance of this species have to be understood in a synecological context and by integrating a variety of stressors other than temperature. By capturing and examining juvenile and adult Allis shad from River Rhine, we demonstrated the first natural reproduction of A. alosa in River Rhine since nearly 100 years and the success of stocking measures within the framework of the LIFE project.
Confidentiality, integrity, and availability are often listed as the three major requirements for achieving data security and are collectively referred to as the C-I-A triad. Confidentiality of data restricts the data access to authorized parties only, integrity means that the data can only be modified by authorized parties, and availability states that the data must always be accessible when requested. Although these requirements are relevant for any computer system, they are especially important in open and distributed networks. Such networks are able to store large amounts of data without having a single entity in control of ensuring the data's security. The Semantic Web applies to these characteristics as well as it aims at creating a global and decentralized network of machine-readable data. Ensuring the confidentiality, integrity, and availability of this data is therefore also important and must be achieved by corresponding security mechanisms. However, the current reference architecture of the Semantic Web does not define any particular security mechanism yet which implements these requirements. Instead, it only contains a rather abstract representation of security.
This thesis fills this gap by introducing three different security mechanisms for each of the identified security requirements confidentiality, integrity, and availability of Semantic Web data. The mechanisms are not restricted to the very basics of implementing each of the requirements and provide additional features as well. Confidentiality is usually achieved with data encryption. This thesis not only provides an approach for encrypting Semantic Web data, it also allows to search in the resulting ciphertext data without decrypting it first. Integrity of data is typically implemented with digital signatures. Instead of defining a single signature algorithm, this thesis defines a formal framework for signing arbitrary Semantic Web graphs which can be configured with various algorithms to achieve different features. Availability is generally supported by redundant data storage. This thesis expands the classical definition of availability to compliant availability which means that data must only be available as long as the access request complies with a set of predefined policies. This requirement is implemented with a modular and extensible policy language for regulating information flow control. This thesis presents each of these three security mechanisms in detail, evaluates them against a set of requirements, and compares them with the state of the art and related work.
This thesis presents novel approaches for integrating context information into probabilistic models. Data from social media is typically associated with metadata, which includes context information such as timestamps, geographical coordinates or links to user profiles. Previous studies showed the benefits of using such context information in probabilistic models, e.g.\ improved predictive performance. In practice, probabilistic models which account for context information still play a minor role in data analysis. There are multiple reasons for this. Existing probabilistic models often are complex, the implementation is difficult, implementations are not publicly available, or the parameter estimation is computationally too expensive for large datasets. Additionally, existing models are typically created for a specific type of content and context and lack the flexibility to be applied to other data.
This thesis addresses these problems by introducing a general approach for modelling multiple, arbitrary context variables in probabilistic models and by providing efficient inference schemes and implementations.
In the first half of this thesis, the importance of context and the potential of context information for probabilistic modelling is shown theoretically and in practical examples. In the second half, the example of topic models is employed for introducing a novel approach to context modelling based on document clusters and adjacency relations in the context space. They can cope with areas of sparse observations and These models allow for the first time the efficient, explicit modelling of arbitrary context variables including cyclic and spherical context (such as temporal cycles or geographical coordinates). Using the novel three-level hierarchical multi-Dirichlet process presented in this thesis, the adjacency of ontext clusters can be exploited and multiple contexts can be modelled and weighted at the same time. Efficient inference schemes are derived which yield interpretable model parameters that allow analyse the relation between observations and context.
Gegenstand der Dissertation ist der Handlungsspielraum der schwarz-gelben Bundesregierung unter der Führung Angela Merkels vor dem Hintergrund der Staatsschuldenkrise im Euroraum von 2009 bis 2013. Ausgehend von der Hypothese, dass sich im Rahmen von Krisen der Bewegungskorridor von Regierungen verringert, wurden strukturelle, inhaltliche und prozessuale Beschränkungen der Bundesregierung in der 17. Legislaturperiode mittels qualitativer und quantitativer Methoden untersucht. Im Ergebnis konnte seit Ausbruch der Eurokrise eine Reduzierung der Handlungsmöglichkeiten der Exekutive festgestellt werden.
The application of pesticides to agricultural areas can result in transport to adjacent non-target environments. In particular, surface water systems are likely to receive agricultural pesticide input. When pesticides enter aquatic environments, they may pose a substantial threat to the ecological integrity of surface water systems. To minimize the risk to non-target ecosystems the European Union prescribes an ecotoxicological risk assessment within the registration procedure of pesticides, which consists of an effect and an exposure assessment.
This thesis focuses on the evaluation of the exposure assessment and the implications to the complete regulatory risk assessment, and is based on four scientific publications. The main part of the thesis focuses on evaluation of the FOCUS modelling approach, which is used in regulatory risk assessment to predict pesticide surface water concentrations. This was done by comparing measured field concentrations (MFC) of agricultural insecticides (n = 466) and fungicides (n = 417) in surface water to respective predicted environmental concentrations (PEC) calculated with FOCUS step 1 to step 4 at two different levels of field relevance. MFCs were extracted from the scientific literature and were measured in field studies conducted primarily in Europe (publications 1 and 3).
In addition, an alternative fugacity-based multimedia mass-balance model, which needs fewer input parameters and less computing effort, was used to calculate PECs for the same insecticide MFC dataset and compared to the FOCUS predictions (publication 3). Furthermore, FOCUS predictions were also conducted for veterinary pharmaceuticals in runoff from an experimental plot study, to assess the FOCUS predictions for a different class of chemicals with a different relevant entry pathway (publication 2).
In publication 4, the FOCUS step-3 approach was used to determine relevant insecticide exposure patterns. These patterns were analysed for different monitoring strategies and the implications for the environmental risk assessment (publication 4).
The outcome of this thesis showed that the FOCUS modelling approach is neither protective nor appropriate in predicting insecticide and fungicide field concentrations. Up to one third of the MFCs were underpredicted by the model calculations, which means that the actual risk might be underestimated. Furthermore, the results show that a higher degree of realism even reduces the protectiveness of model results and that the model predictions are worse for highly hydrophobic and toxic pyrethroids.
In addition, the absence of any relationship between measured and predicted concentrations questions the general model performance quality (publication 1 and 3). Further analyses revealed that deficiencies in protectiveness and predictiveness of the environmental exposure assessment might even be higher than shown in this thesis, because actual short-term peak concentrations are only detectable with an event-related sampling strategy (publication 4). However, it was shown that the PECs of a much simpler modelling approach are much more appropriate for the prediction of insecticide MFC, especially for calculations with a higher field relevance (publication 3). The FOCUS approach also failed to predict concentrations of veterinary pharmaceuticals in runoff water (publication 2). In conclusion, the findings of this thesis showed that there is an urgent need for the improvement of exposure predictions conducted in the environmental risk assessment of pesticides as a group of highly relevant environmental chemicals, to ensure that the increasing use of those chemicals does not lead to further harmful effects in aquatic ecosystems.
The establishment of aquatic alien species can strongly affect community and food web structure of the invaded systems and thus represents a major threat to native biodiversity. One of the most important aquatic invasive species in European rivers is the Ponto-Caspian amphipod Dikerogammarus villosus. The species invaded most of the major European waterways within two decades, often associated with a decline of many other macroinvertebrate species, including other amphipods. Based on laboratory results predation by the so called ‘killer shrimp’ is often regarded as the key driver for observed displacement effects, but recent studies indicated a minor relevance of predation by D. villosus in the field. To allow the determination of exact predator-prey interactions from field samples, I established 22 group-specific rDNA primers for freshwater taxa suitable for prey species identification in dietary samples (Chapter II) and an approach for the screening of D. villosus gut contents using 16 of these primers. Combining genetic gut content analyses, with one of these primers, and stable isotope analyses, I examined the importance of intraguild predation (IGP) by D. villosus, which is often assumed the key driver for the displacement of native amphipod species, at an invasion front of the species in Switzerland (Chapter III). The results of this study revealed a low importance of IGP during this particular D. villosus invasion and indicated an overall sparsely predacious feeding behaviour of the species. As the feeding behaviour of D. villosus is supposed to differ between habitats and this study was only conducted at a few sampling sites of one river, I also investigated the role of predation by D. villosus at multiple sites of the River Rhine system, covering a broad range of microhabitats (Chapter IV). In keeping with the results from the invasion front results of this study strongly indicated a sparsely predacious feeding but rather a flexible feeding behaviour of D. villosus even within the same microhabitat.
However, established populations of D. villosus have changed aquatic food webs and can be expected to affect aquatic-terrestrial energy fluxes. In Chapter V of my thesis, I present a field study investigating the impact of D. villosus on the diet of two riparian spider taxa. The results of this study indicate an effect of D. villosus on the terrestrial food web via cross-ecosystem resource flow.
In conclusion, D. villosus influences terrestrial food webs by altering cross-ecosystem resource fluxes, but it is rather an opportunistic omnivore than a predator in the field.
Die vorliegende Arbeit beschäftigt sich mit der Fragestellung, wie eine repräsentative und aussagekräftige Vergleichbarkeit hinsichtlich der Nachhaltigkeitsleistung (Ökoeffizienz) von Unternehmen branchenunabhängig gewährleistet werden kann trotz der Problematik der Definition repräsentativer Bewertungskriterien der Nachhaltigkeit, sowie der Heterogenität der zu bewertenden Branchen. Bisherige Konzepte zu Umwelt- und Nachhaltigkeitsmanagementsystemen (z.B. EMAS, ISO 14000, ISO 26000, EMASplus), zur Umweltleistungsmessung sowie zur Nachhaltigkeitsbewertung und -berichterstattung (z.B. DNK, GRI) sind mit ihren branchenunabhängigen Formulierung zu allgemein gehalten, um für eine konkrete effizienzorientierte Messung nachhaltigen Wirtschaftens von Unternehmen geeignet zu sein.
Folglich besteht kein System zur Messung der Umweltleistung, um den Forschungsbedarf der Herstellung einer aussagekräftigen Vergleichbarkeit der Ressourcen- und Energieverbräuche der Betriebe einer heterogenen Branche zu begegnen. Angesichts dessen wurde im Rahmen der Arbeit eine allgemeine und branchenunabhängig anwendbare aber dennoch –spezifische Methodik zur Herstellung der Vergleichbarkeit von Unternehmen einer Branche hinsichtlich der Ressourcen- und Energieeffizienz entwickelt. Dabei stellt der Kern der Methodik die Generierung eines betriebsindividuellen Gesamtgewichtungsfaktors dar (GGF-Konzept), welcher als Operationalisierung der Vergleichbarkeit angesehen werden kann und damit der Problematik der Heterogenität begegnet. Die Ermittlung von Kriteriengewichtungen im Rahmen des GGF-Konzeptes kann in Analogie zu einem Entscheidungsproblem bei Mehrfachzielsetzung (Multi Criteria Decision Making – MCDM) gesehen werden, da mehrere Kriterien und Sub-Kriterien zueinander in Relation gesetzt werden mussten. Infolgedessen stellte sich der Analytische-Hierarchie-Prozess als das geeignete Verfahren im Rahmen der Methodikentwicklung heraus. Anwendung fand die Methodik in einem ersten empirischen Test anhand einer ausgewählten Stichprobe von 40 Wäschereibetrieben. Dabei zeigten die Ergebnisse auf, dass repräsentatives sowie aussagekräftiges betriebsindividuelles Benchmarking der Ressourcen- und Energieverbräuche völlig unterschiedlicher und bislang nicht vergleichbarer Betriebe möglich wurde. Hierfür mussten zunächst branchenspezifische repräsentative Bewertungskriterien der Ressourcen- und Energieeffizienz bestimmt werden. Abschließend konnten betriebsspezifische Brennpunkte identifiziert und somit Handlungsempfehlungen zur Optimierung der Ressourcen- und Energieeffizienz der Wäschereibetriebe abgeleitet werden, sodass eine zielorientierte Reduzierung des Ressourcen- und Energieverbrauchs folgen kann.
Conversion of natural vegetation into cattle pastures and croplands results in altered emissions of greenhouse gases (GHG), such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Their atmospheric concentration increase is attributed the main driver of climate change. Despite of successful private initiatives, e.g. the Soy Moratorium and the Cattle Agreement, Brazil was ranked the worldwide second largest emitter of GHG from land use change and forestry, and the third largest emitter from agriculture in 2012. N2O is the major GHG, in particular for the agricultural sector, as its natural emissions are strongly enhanced by human activities (e.g. fertilization and land use changes). Given denitrification the main process for N2O production and its sensitivity to external changes (e.g. precipitation events) makes Brazil particularly predestined for high soil-derived N2O fluxes.
In this study, we followed a bottom-up approach based on a country-wide literature research, own measurement campaigns, and modeling on the plot and regional scale, in order to quantify the scenario-specific development of GHG emissions from soils in the two Federal States Mato Grosso and Pará. In general, N2O fluxes from Brazilian soils were found to be low and not particularly dynamic. In addition to that, expected reactions to precipitation events stayed away. These findings emphasized elaborate model simulations in daily time steps too sophisticated for regional applications. Hence, an extrapolation approach was used to first estimate the influence of four different land use scenarios (alternative futures) on GHG emissions and then set up mitigation strategies for Southern Amazonia. The results suggested intensification of agricultural areas (mainly cattle pastures) and, consequently, avoided deforestation essential for GHG mitigation.
The outcomes of this study provide a very good basis for (a) further research on the understanding of underlying processes causing low N2O fluxes from Brazilian soils and (b) political attempts to avoid new deforestation and keep GHG emissions low.
Die Entstehung von Gründungsteams wird bisher lediglich als Abfolge von Suche, Auswahl und Gewinnung von Gründerpersonen verstanden. In der vorliegenden Arbeit wird auf Basis von 47 interviewten Gründerpersonen ein neues Verständnis für die Entstehung von Gründungsteams geschaffen. Dabei wird im Stil der Grounded Theory das bisher vorherrschende Model der Teamentstehung maßgeblich erweitert. So wird eine neue Art der Unterscheidung von Grünerpersonen entdeckt, welche auf die Intention von Teammitgliedern abzielt. Zudem zeigt sich, dass Teams in einem iterativ-epiodischen Prozess entstehen und Veränderungen von Teamzu-sammmensetzungen Bestandteil der Entstehung sind. Aufgrund der in dieser Arbeit geschaffenen neuen Erkenntnisse zur Teamentstehung können Handlungsempfehlungen für Gründerpersonen und die Gründungsförderung gegeben werden. Zudem werden neue Untersuchungsgebiete für Gründungsteams eröffnet, die das hier entwickelte Modell als Bezugsrahmen für weitere Forschung nehmen können.
Reactive local algorithms are distributed algorithms which suit the needs of battery-powered, large-scale wireless ad hoc and sensor networks particularly well. By avoiding both unnecessary wireless transmissions and proactive maintenance of neighborhood tables (i.e., beaconing), such algorithms minimize communication load and overhead, and scale well with increasing network size. This way, resources such as bandwidth and energy are saved, and the probability of message collisions is reduced, which leads to an increase in the packet reception ratio and a decrease of latencies.
Currently, the two main application areas of this algorithm type are geographic routing and topology control, in particular the construction of a node's adjacency in a connected, planar representation of the network graph. Geographic routing enables wireless multi-hop communication in the absence of any network infrastructure, based on geographic node positions. The construction of planar topologies is a requirement for efficient, local solutions for a variety of algorithmic problems.
This thesis contributes to reactive algorithm research in two ways, on an abstract level, as well as by the introduction of novel algorithms:
For the very first time, reactive algorithms are considered as a whole and as an individual research area. A comprehensive survey of the literature is given which lists and classifies known algorithms, techniques, and application domains. Moreover, the mathematical concept of O- and Omega-reactive local topology control is introduced. This concept unambiguously distinguishes reactive from conventional, beacon-based, topology control algorithms, serves as a taxonomy for existing and prospective algorithms of this kind, and facilitates in-depth investigations of the principal power of the reactive approach, beyond analysis of concrete algorithms.
Novel reactive local topology control and geographic routing algorithms are introduced under both the unit disk and quasi unit disk graph model. These algorithms compute a node's local view on connected, planar, constant stretch Euclidean and topological spanners of the underlying network graph and route messages reactively on these spanners while guaranteeing the messages' delivery. All previously known algorithms are either not reactive, or do not provide constant Euclidean and topological stretch properties. A particularly important partial result of this work is that the partial Delaunay triangulation (PDT) is a constant stretch Euclidean spanner for the unit disk graph.
To conclude, this thesis provides a basis for structured and substantial research in this field and shows the reactive approach to be a powerful tool for algorithm design in wireless ad hoc and sensor networking.
In Part I: "The flow-decomposition problem", we introduce and discuss the flow-decomposition problem. Given a flow F, this problem consists of decomposing the flow into a set of paths optimizing specific properties of those paths. We introduce different types of decompositions, such as integer decompositions and alpha-decompositions, and provide two formulations of the set of feasible decompositions.
We show that the problem of minimizing the longest path in a decomposition is NP-hard, even for fractional solutions. Then we develop an algorithm based on column generation which is able to solve the problem.
Tight upper bounds on the optimal objective value help to improve the performance.
To find upper bounds on the optimal solution for the shortest longest path problem, we develop several heuristics and analyze their quality. On pearl graphs we prove a constant approximation ratio of 2 and 3 respectively for all heuristics. A numerical study on random pearl graphs shows that the solutions generated by the heuristics are usually much better than this worst-case bound.
In Part II: "Construction and analysis of evacuation models using flows over time", we consider two optimization models in the context of evacuation planning. The first model is a parameter-based quickest flow model with time-dependent supply values. We give a detailed description of the network construction and of how different scenarios are modeled by scenario parameters. In a second step we analyze the effect of the scenario parameters on the evacuation time. Understanding how the different parameters influence the evacuation time allows us to provide better advice for evacuation planning and allows us to predict evacuation times without solving additional optimization problems. To understand the effect of the time-dependent supply values, we consider the quickest path problem with time-dependent supply values and provide a solution algorithm. The results from this consideration are generalized to approximate the behavior of the evacuation times in the context of quickest flow problems.
The second model we consider is a path-based model for evacuation in the presence of a dynamic cost function. We discuss the challenges of this model and provide ideas for how to approach the problem from different angles. We relate the problem to the flow-decomposition problem and consider the computation of evacuation paths with dynamic costs for large capacities. For the latter method we provide heuristics to find paths and compare them to the optimal solutions by applying the methods to two evacuation scenarios. An analysis shows that the paths generated by the heuristic yield close to optimal solutions and in addition have several desirable properties for evacuation paths which are not given for the optimal solution.
Risiko-Träger Controlling: Identifizierung und Bewältigungsoptionen im Kontext dialogischer Führung
(2016)
Management control seen as an element of the management process is assigned with a broad range of tasks and functions within organizations. Its role throughout risk- and goal-oriented management schemes is well established in both theory and organizational practice but its contribution to risks within the management cycle is scarcely discussed in scholarly literature. This blind spot is taken up by this research paper aiming to identify the institutionalized controlling as a risk-bearing actor within organizational management and outlining options to cover it.
Immer häufiger kommt es zum Einsatz von Servicepersonal in Krankenhäusern und anderen pflegerischen Einrichtungen um dem Fachkräftemangel in der Pflege zu kompensieren. Die vorliegende Arbeit zeigt eine Kompatibilität von Tätigkeiten von Servicepersonal und Professionstheorien der Pflege, sowie einen Lernbedarf für Servicepersonal im Setting der stationären Pflege im Krankenhaus.
Pflegeexperten sind der Meinung, dass ein Einsatz von Servicepersonal, das in der Lage ist, durch definierte Tätigkeiten und Anforderungen Pflegepersonal zu unterstützen, notwendig ist. Zur Entwicklung von Handlungskompetenz für ausgewählte Tätigkeiten bietet ein situatives, tätigkeitsbezogenes Anforderungsprofil, gegliedert nach dem Kompetenzmodell in persönliche, soziale, methodische und fachliche Kompetenz, eine Grundlage für eine Bildungsmaßnahme für Servicepersonal.
Die Erkenntnisse dieser Arbeit tragen einen Teil dazu bei, den gegenwärtigen und künftigen Herausforderungen der Pflege gewachsen zu sein.
Ein zentrales Problem der stationären Behandlung psychischer und psychosomatischer Störungen ist die Nachhaltigkeit von Therapieerfolgen. Im Rahmen einer Pilotstudie wurde ein SMS-basiertes Nachsorgeprogramm zur Modifikation Perfektionismus-bezogener Kognitionen im Anschluss an eine stationäre Behandlung von Burnout-Patienten evaluiert.
Es handelte sich um eine kontrollierte Verlaufsstudie mit vier Messzeitpunkten (Aufnahme, Entlassung, 6 und 10-Wochen-Katamnese). Die Patienten der Versuchsgruppe (n=31) erhielten zusätzlich zur Routine-Behandlung eine 6-wöchige kognitiv ausgerichtete individualisierte SMS-Nachsorge. Als Kontrollgruppe (n=30) diente eine Gruppe von Patienten mit einer stationären Routine-Behandlung. Zur Erfassung der Burnout-Symptomatik wurde das Maslach Burnout Inventory General Survey (MBI-GS-D) eingesetzt, die depressive Symptomatik wurde mit dem Beck-Depressions-Inventar-V (BDI-V) erhoben. Zur Erfassung der Facetten des Perfektionismus dienten Items aus der Multidimensional Perfectionism Scale (FMPS und HMPS) sowie der Almost Perfect Scale (APS-R).
Ein sehr hohes Interesse, eine hohe Inanspruchnahme sowie eine hohe Akzeptanz des Nachsorgeprogramms konnte anhand der Bereitschaft zur Teilnahme und der von den Teilnehmern bewertete Nutzen aufgezeigt werden.
Eine Wirksamkeit der SMS-Nachsorge bzgl. Burnout und depressiver Symptomatik sowie dysfunktionalen Facetten des Perfektionismus konnte mittels zweifaktoriellen Kovarianzanalysen (Gruppe, Zeit, Baseline als Kovariate) nicht nachgewiesen werden. Ein Grund hierfür könnte sein, dass der Interventionszeitraum von 10 Wochen nach der stationären Entlassung für eine effektive Nachsorge zu kurz bemessen wurde. Bzgl. einiger dysfunktionaler Perfektionismusskalen (Concern over Mistakes, Discrepancy, Socially Prescribed Perfectionism) zeigten sich kleinere Interaktionseffekte, die einen ersten Hinweis liefern, dass die eingesetzten SMS-Nachrichten Perfektionismus-bezogene Kognitionen verändern können. Da das vorgestellte Interventionsprogramm ein ökonomisches und niedrigschwelliges ambulantes Nachsorge-Konzept darstellt und sich erste Hinweise auf eine Wirksamkeit ergeben, wären für die Zukunft weitere Studien wünschenswert, die sich über einen längeren Interventionszeitraum erstrecken. Es sollten weitere Messinstrumente einbezogen und die Implementierung eines Feedbackprozesses erwogen werden.
The (un-)controlled application of olive oil mill wastewater (OMW) has positive and negative effects on soil quality. On the one hand it can be used as fertilizer, on the other hand especially the occurrence of soil water repellency is problematic. Due to this fact the objective of this study was to characterize the effects of OMW application on soil and to investigate the mechanisms that are in combination with changes of soil organic matter quality responsible for soil water repellency depending on the climatic conditions.
At first several locations of uncontrolled OMW disposal were screened for positive and negative im-pacts. Then, laboratory incubation experiments and finally a field experiment in Israel were conducted in order to determine the influence of climatic conditions. Besides standard soil parameters (pH, elec-tric conductivity, total carbon, dissolved organic carbon , specific UV-Absorption) it was focused on the determination of phenolic compounds, the carbon isotope ratio, the water drop penetration time and the contact angle as well as the thermal analysis.
This thesis shows that soil water repellency of OMW-polluted soils depends on the climatic conditions, i.e. the application season. In the laboratory as well as in the field the wettability of the soil was strongly reduced under hot and dry conditions. It was observed, that the stable carbon fraction characterized by a high calorific value is responsible for soil water repellency. In particular, amphiphilic substances, e.g. fatty acids, may interact with soil particles as a consequence of drying. On the contrary, no reduc-tion of the wettability of the soil was determined under moist conditions and degradation of organic matter of the OMW was enhanced. Nevertheless, too strong irrigation or rainfall, e.g. in winter, may leach phenolic ingredients of the OMW into the groundwater.
At the same time the application led to an increase of organic and inorganic nutrients, which should be emphasized as a positive effect. Due to these results, a controlled application of olive oil mill wastewater as alternative, low-cost and sustainable treatment option is recommended. But, instead of the current application season winter, the olive mill wastewater should be stored and not be spread before spring in order to avoid negative impacts on the soil.
Science education has been facing important challenges in the recent years: the decline in student’s interest in scientific topics, and moreover, the decrease of students pursuing science beyond their compulsory studies (Bennett, Hogarth, Lubben, 2003). As a result, research has focus on examining different approaches that could attempt to improve the situation. One of these approaches has been the use of context-based problem-solving tasks (Kölbach & Sumfleth, 2011; Bennett, Hogarth, Lubben, 2003). While research into context-based problem-solving tasks suggest that they are very motivating for students, it is still unclear how they influence motivation. Following an experimental pretest-postest design, two studies examined the effects of context-based task characteristics of contextualization, complexity, and transparency, on students’ motivational variables, performance, and metacognitive experiences.
Results from both studies suggest that the task characteristic of contextualization directly influences how students’ interest is triggered and maintained throughout the task. On the other hand, the task characteristics of complexity and transparency had different effects for the other dependent variables of effort, difficulty, and solution correctness.
Moreover, data shows that other motivational variables such as anxiety and success expectancies are strongly influenced by the interaction of the parameters under study. The dissertation concludes that appropriate design and use of context-based task characteristics can benefit students’ learning processes and outcomes.
Externe Repräsentationen spielen eine wichtige Rolle für die Lösung von mathematischen Textaufgaben. Die vorliegende Studie untersucht die Effekte bereitgestellter Repräsentationen beim Lösen problemhaltiger Textaufgaben in der Grundschule. Insbesondere problemhaltige Textaufgaben sind für Schüler anspruchsvoll, da sie nicht direkt mit den eingeübten und routinierten Rechenoperationen gelöst werden können. Sie zeichnen sich dadurch aus, dass sich der Lösungsweg nicht auf einen Blick erschließt, die mathematische Grundstruktur daher zunächst erkannt, entfaltet und verstanden werden muss und häufig mehrere Aufgabenbedingungen bei der Planung und Beschreitung des Lösungswegs bedacht und verarbeitet werden müssen. Um diesen komplexen Anforderungen begegnen zu können, benötigen Schüler die Fähigkeit, das Problem adäquat zu repräsentieren. Dabei können verschiedene Darstellungsformen wie Zeichnungen und Tabellen verwendet werden, die dann als Werkzeuge für die kognitiven Lösungsprozesse dienen. Da Grundschüler von sich aus häufig keine externen Repräsentationen erstellen, geht die vorliegende Studie den Fragen nach, (1) ob vorgefertigte Repräsentationen das Problemlösen verbessern und erleichtern, (2) ob sich eine Auseinandersetzung mit vorgefertigten Tabellen und Zeichnungen auch auf späteres Problemlösen ohne bereitgestellte Hilfsmittel auswirkt, (3) welche Repräsentationsform (Zeichnung oder Tabelle) und (4) wie viel Vorstrukturierung der bereitgestellten Repräsentation dabei hilfreicher ist. In einem experimentellen Studiendesign arbeiteten 199 Viertklässler an unterschiedlichen problemhaltigen Textaufgaben. Das Design bestand aus drei Tests: (1) Vor-, (2) Treatment- und (3) Transfertest. Im Vortest wurde die Ausgangsleistung der Probanden bei problemhaltigen Textaufgaben gemessen. Im Treatment-Test wurde die Performance beim Problemlösen mit vorgegebenen Repräsentationen erhoben: Probanden der Experimentalgruppe erhielten Zeichnungen und Tabellen in unterschiedlichen Vorstrukturierungsgraden zu den Aufgaben (Intervention), eine Kontrollgruppe erhielt keine Repräsentationen. Im Transfertest bearbeiteten die Teilnehmer vergleichbare Aufgaben wiederum ohne vorgegebene Repräsentationen, um die Problemlöse-Performance nach der Intervention zu messen. Die Ergebnisse zeigten erstens, dass die bereitgestellten Repräsenta-tionen entgegen der Annahme die Problemlöseprozesse insgesamt nicht verbessert und erleichtert haben. Zweitens: Wurde eine Repräsentation bereitgestellt, war eine Zeichnung wie angenommen hilfreicher als eine Tabelle. Jedoch war dieser Effekt abhängig vom Problemtyp und vom Grad der Vorstrukturierung. Offensichtlich genügte es nicht, Zeichnungen und Tabellen einfach nur bereitzustellen, da die Probanden vielfach Schwierigkeiten bei der Interpretation und adäquaten Verwendung der Repräsentationen hatten. Dies spricht für die Notwendigkeit eines Trainings zur Ausbildung und Förderung einer frühen „diagram literacy“ bereits bei Grundschülern.
While reading this sentence, you probably gave (more or less deliberately) instructions to approximately 100 to 200 muscles of your body. A sceptical face or a smile, your fingers scrolling through the text or holding a printed version of this work, holding your head, sitting, and much more.
All these processes take place almost automatically, so they seem to be no real achievement. In the age of digitalization it is a defined goal to transfer human (psychological and physiological) behavior to machines (robots). However, it turns out that it is indeed laborious to obtain human facial expression or walking from robots. To optimize this transfer, a deeper understanding of a muscle's operating principle is needed (and of course an understanding of the human brain, which will, however, not be part of this thesis).
A human skeletal muscle can be shortened willingly, but not lengthened, thereto it takes an antagonist. The muscle's change in length is dependent on the incoming stimulus from the central nervous system, the current length of the muscle itself, and certain muscle--specific quantities (parameters) such as the maximum force. Hence, a muscle can be mathematically described by a differential equation (or more exactly a coupled differential--algebraic system, DAE), whose structure will be revealed in the following chapters. The theory of differential equations is well-elaborated. A multitude of applicable methods exist that may not be known by muscle modelers. The purpose of this work is to link the methods from applied mathematics to the actual application in biomechanics.
The first part of this thesis addresses stability theory. Let us remember the prominent example from middle school physics, in which the resting position of a ball was obviously less susceptible towards shoves when lying in a bowl rather than balancing at the tip of a hill. Similarly, a dynamical (musculo-skeletal) system can attain equilibrium states that react differently towards perturbations.
We are going to compute and classify these equilibria.
In the second part, we investigate the influence of individual parameters on model equations or more exactly their solutions. This method is known as sensitivity analysis.
Take for example the system "car" containing a value for the quantity "pressure on the break pedal while approaching a traffic light". A minor deviation of this quantity upward or downward may lead to an uncomfortable, abrupt stop or even to a collision, instead of a smooth stop with a sufficient gap.
The considered muscle model contains over 20 parameters that, if changed slightly, have varying effects on the model equation solutions at different instants of time. We will investigate the sensitivity of those parameters regarding different sub--models, as well as the whole model among different dynamical boundary conditions.
The third and final part addresses the \textit{optimal control} problem (OCP).
The muscle turns a nerve impulse (input or control) into a length change and therefore a force response (output). This forward process is computable by solving the respective DAE. The reverse direction is more difficult to manage. As an everyday example, the OCP is present regarding self-parking cars, where a given path is targeted and the controls are the position of the
steering wheel as well as the gas pedal.
We present two methods of solving OCPs in muscle modeling: the first is a conjunction of variational calculus and optimization in function spaces, the second is a surrogate-based optimization.
The provision of electronic participation services (e-participation) is a complex socio-technical undertaking that needs comprehensive design and implementation strategies. E-participation service providers, in the most cases administrations and governments, struggle with changing requirements that demand more transparency, better connectivity and increased collaboration among different actors. At the same time, less staff are available. As a result, recent research assesses only a minority of e-participation services as successful. The challenge is that the e-participation domain lacks comprehensive approaches to design and implement (e-)participation services. Enterprise Architecture (EA) frameworks have evolved in information systems research as an approach to guide the development of complex socio-technical systems. This approach can guide the design and implementation services, if the collection of organisations with the commonly held goal to provide participation services is understood as an E Participation Enterprise (EE). However, research & practice in the e participation domain has not yet exploited EA frameworks. Consequently, the problem scope that motivates this dissertation is the existing gap in research to deploy EA frameworks in e participation design and implementation. The research question that drives this research is: What methodical and technical guides do architecture frameworks provide that can be used to design and implement better and successful e participation?
This dissertation presents a literature study showing that existing approaches have not covered yet the challenges of comprehensive e participation design and implementation. Accordingly, the research moves on to investigate established EA frameworks such as the Zachman Framework, TOGAF, the DoDAF, the FEA, the ARIS, and the ArchiMate for their use. While the application of these frameworks in e participation design and implementation is possible, an integrated approach is lacking so far. The synthesis of literature review and practical insights in design and implementation of e participation services from four projects show the challenges of adapting architecture frameworks for this domain. However, the research shows also the potential of a combination of the different approaches. Consequently, the research moves on to develop the E-Participation Architecture Framework (EPART-Framework). Therefore, the dissertation applies design science research including literature review and action research. Two independent settings test an initial EPART-Framework version. The results yield into the EPART-Framework presented in this dissertation.
The EPART-Framework comprises of the EPART-Metamodel with six EPART-Viewpoints, which frame the stakeholder concerns: the Participation Scope, the Participant Viewpoint, the Participation Viewpoint, the Data & Information Viewpoint, the E-participation Viewpoint, and Implementation & Governance Viewpoint. The EPART-Method supports the stakeholders to design the EE and implement e participation and stores its output in an architecture description and a solution repository. It consists of five consecutive phases accompanied by requirements management: Initiation, Design, Implementation and Preparation, Participation, and Evaluation. The EPART-Framework fills the gap between the e participation domain and the enterprise architecture framework domain. The evaluation gives reasonable evidence that the framework is a valuable addition in academia and in practice to improve e-participation design and implementation. The same time, it shows opportunities for future research to extend and advance the framework.
One of the main goals of the artificial intelligence community is to create machines able to reason with dynamically changing knowledge. To achieve this goal, a multitude of different problems have to be solved, of which many have been addressed in the various sub-disciplines of artificial intelligence, like automated reasoning and machine learning. The thesis at hand focuses on the automated reasoning aspects of these problems and address two of the problems which have to be overcome to reach the afore-mentioned goal, namely 1. the fact that reasoning in logical knowledge bases is intractable and 2. the fact that applying changes to formalized knowledge can easily introduce inconsistencies, which leads to unwanted results in most scenarios.
To ease the intractability of logical reasoning, I suggest to adapt a technique called knowledge compilation, known from propositional logic, to description logic knowledge bases. The basic idea of this technique is to compile the given knowledge base into a normal form which allows to answer queries efficiently. This compilation step is very expensive but has to be performed only once and as soon as the result of this step is used to answer many queries, the expensive compilation step gets worthwhile. In the thesis at hand, I develop a normal form, called linkless normal form, suitable for knowledge compilation for description logic knowledge bases. From a computational point of view, the linkless normal form has very nice properties which are introduced in this thesis.
For the second problem, I focus on changes occurring on the instance level of description logic knowledge bases. I introduce three change operators interesting for these knowledge bases, namely deletion and insertion of assertions as well as repair of inconsistent instance bases. These change operators are defined such that in all three cases, the resulting knowledge base is ensured to be consistent and changes performed to the knowledge base are minimal. This allows us to preserve as much of the original knowledge base as possible. Furthermore, I show how these changes can be applied by using a transformation of the knowledge base.
For both issues I suggest to adapt techniques successfully used in other logics to get promising methods for description logic knowledge bases.
The global problematic issue of the olive oil industry is in its generation of large amounts of olive mill wastewater (OMW). The direct discharge of OMW to the soil is very common which presents environmental problems for olive oil producing countries. Both, positive as well as negative effects on soil have been found in earlier studies. Therefore, the current study hypothesized that whether beneficial effects or negative effects dominate depends on the prevailing conditions before and after OMW discharge to soil. As such, a better understanding of the OMW-soil interaction mechanisms becomes essential for sustainable safe disposal of OMW on soil and sustainable soil quality.
A field experiment was carried out in an olive orchard in Palestine, over a period of 24 months, in which the OMW was applied to the soil as a single application of 14 L m-2 under four different environmental conditions: in winter (WI), spring (SP), and summer with and without irrigation (SUmoist and SUdry). The current study investigated the effects of seasonal conditions on the olive mill wastewater (OMW) soil interaction in the short-term and the long-term. The degree and persistence of soil salinization, acidification, accumulation of phenolic compounds and soil water repellency were investigated as a function of soil depth and time elapsed after the OMW application. Moreover, the OMW impacts on soil organic matter SOM quality and quantity, total organic carbon (SOC), water-extractable soil organic carbon (DOC), as well as specific ultraviolet absorbance analysis (SUVA254) were also investigated for each seasonal application in order to assess the degree of OMW-OM decomposition or accumulation in soil, and therefore, the persisting effects of OMW disposal to soil.
The results of the current study demonstrate that the degree and persistence of relevant effects due to OMW application on soil varied significantly between the different seasonal OMW applications both in the short-term and the long-term. The negative effects of the potentially hazardous OMW residuals in the soil were highly dependent on the dominant transport mechanisms and transformation mechanisms, triggered by the ambient soil moisture and temperature which either intensified or diminished negative effects of OMW in the soil during and after the application season. The negative effects of OMW disposal to the soil decreased by increasing the retention time of OMW in soil under conditions favoring biological activity. The moderate conditions of soil moisture and temperature allowed for a considerable amount of applied OMW to be biologically degraded, while the prolonged application time under dry conditions and high temperature resulted in a less degradable organic fraction of the OMW, causing the OMW constituents to accumulate and polymerize without being degraded. Further, the rainfall during winter season diminished negative effects of OMW in the soil; therefore, the risk of groundwater contamination by non-degraded constituents of OMW can be highly probable during the winter season.
La tesis doctoral examina los tres manuscritos conocidos hasta hoy de la Explicación de la Guitarra, primer método para guitarra de seis órdenes conocido hasta escrito por Juan Antonio de Vargas y Guzmán. Fue escrito primeramente cuando Vargas y Guzmán era vecino de la ciudad de Cádiz, en 1773; y copiado en dos ocasiones cuando el autor era maestro de este instrumento en la Ciudad de Veracruz, en 1776. Después de 200 años, específicamente en 1974, se dio la primera referencia de un manuscrito de este método, fechado en Veracruz en 1776, que se resguardaba en la Biblioteca Newberry de Chicago. Años más tarde, ya en 1980, la doctora María Fernanda García de los Arcos encontró en el Archivo General de la Nación (AGN) la segunda copia manuscrita, con la misma información de lugar y fecha que la anterior, pero que contenía una diferencia sustancial con el primero: 13 Sonatas para guitarra y bajo continuo. El tercero de ellos, fechado en Cádiz en 1773, fue adquirido por el investigador Ángel Medina Álvarez en una librería anticuaria a fines de los años 70; pero no fue sino hasta 1989, que decidió dar noticias de él y publicarlo posteriormente. A su vez, este manuscrito contiene una diferencia sustancial: un Tratado de Rasgueado. Además de esas diferencias sustanciales, la Explicación de la Guitarra, en su conjunto contiene, un Tratado de Punteado y un Tratado de Bajo continuo para guitarra.
El estudio establece la relación entre cada uno de los manuscritos; define sus contenidos y analiza los principios y fundamentos que sustentan las innovaciones de ellos sobre los ya conocidos por el autor; establece la relación entre los contenidos teóricos y prácticos; compara su evolución; los sitúa en un contexto histórico; establece su relación con otros métodos de la misma índole, así como con métodos de características similares; compila sus fuentes y determina la influencia que tuvieron éstas sobre la Explicación de la Guitarra y ésta sobre aquellas; y determina su importancia histórica y teórica en la música para este instrumento.
The work presented in this thesis investigated interactions of selected biophysical processes that affect zooplankton ecology at smaller scales. In this endeavour, the extent of changes in swimming behaviour and fluid disturbances produced by swimming Daphnia in response to changing physical environments were quantified. In the first research question addressed within this context, size and energetics of hydrodynamic trails produced by Daphnia swimming in non-stratified still waters were characterized and quantified as a function of organisms’ size and their swimming patterns.
The results revealed that neither size nor the swimming pattern of Daphnia affects the width of induced trails or dissipation rates. Nevertheless, as the size and swimming velocity of the organisms increased, trail volume increased in proportional to the cubic power of Reynolds number, and the biggest trail volume was about 500 times the body volume of the largest daphnids. Larger spatial extent of fluid perturbation and prolonged period to decay caused by bigger trail volumes would play a significant role in zooplankton ecology, e.g. increasing the risk of predation.
The study also found that increased trail volume brought about significantly enhanced total dissipated power at higher Reynolds number, and the magnitudes of total dissipated power observed varied in the range of (1.3-10)X10-9 W.
Furthermore, this study provided strong evidence that swimming speed of Daphnia and total dissipated power in Daphnia trails exceeded those of some other selected zooplankton species.
In recognizing turbulence as an intrinsic environmental perturbation in aquatic habitats, this thesis also examined the response of Daphnia to a range of turbulence flows, which correspond to turbu-lence levels that zooplankton generally encounter in their habitats. Results indicated that within the range of turbulent intensities to which the Daphnia are likely to be exposed in their natural habitats, increasing turbulence compelled the organisms to enhance their swimming activity and swim-ming speed. However, as the turbulence increased to extremely high values (10-4 m2s-3), Daphnia began to withdraw from their active swimming behaviour. Findings of this work also demonstrated that the threshold level of turbulence at which animals start to alleviate from largely active swimming is about 10-6 m2s-3. The study further illustrated that during the intermediate range of turbu-lence; 10-7 - 10-6 m2s-3, kinetic energy dissipation rates in the vicinity of the organisms is consistently one order of magnitude higher than that of the background turbulent flow.
Swarming, a common conspicuous behavioural trait observed in many zooplankton species, is considered to play a significant role in defining freshwater ecology of their habitats from food exploitation, mate encountering to avoiding predators through hydrodynamic flow structures produced by them, therefore, this thesis also investigated implications of Daphnia swarms at varied abundance & swarm densities on their swimming kinematics and induced flow field.
The results showed that Daphnia aggregated in swarms with swarm densities of (1.1-2.3)x103 L-1, which exceeded the abundance densities by two orders of magnitude (i.e. 1.7 - 6.7 L-1). The estimated swarm volume decreased from 52 cm3 to 6.5 cm3, and the mean neighbouring distance dropped from 9.9 to 6.4 body lengths. The findings of this work also showed that mean swimming trajectories were primarily horizontal concentric circles around the light source. Mean flow speeds found to be one order of magnitude lower than the corresponding swimming speeds of Daphnia. Furthermore, this study provided evidences that the flow fields produced by swarming Daphnia differed considerably between unidirectional vortex swarming and bidirectional swimming at low and high abundances respectively.
In der vorliegenden Untersuchung stehen geometrische Aufgaben und die in den seit 2004 national verbindlichen Bildungsstandards im Fach Mathematik für den Primarbereich formulierten Anforderungsbereiche im Zentrum. Diese zeigen die kognitiven Anforderungen an Schülerinnen und Schüler bei der Bearbeitung von Aufgaben auf, wobei zwischen „Reproduzieren", „Zusammenhänge herstellen" und „Verallgemeinern und Reflektieren" unterschieden wird (KMK, 2005a, S. 13).
Durch die drei Anforderungsbereiche sollen Lehrkräfte unter anderem die Chance zur Entwicklung einer anforderungsbezogenen Aufgabenkultur erhalten. Des Weiteren soll die Integration von Aufgaben aus allen drei Anforderungsbereichen im Unterricht angeregt und einem einseitig ausgerichteten Unterricht entgegen gewirkt werden.
Da die Anforderungsbereiche bislang nicht empirisch validiert wurden und in den Veröffentlichungen der Kultusministerkonferenz nicht klar zur Schwierigkeit von Aufgaben abgegrenzt werden (KMK, 2005a, S. 13; KMK, 2005b, S. 17; KMK, 2004b, S. 13), wurde in der vorliegenden Untersuchung zum einen die Möglichkeit der eindeutigen Zuordnung geometrischer Aufgaben zu den drei Anforderungsbereichen geprüft.
Zum anderen wurde untersucht, inwiefern die in den geometrischen Aufgaben enthaltenen kognitiven Anforderungen in Zusammenhang mit der empirischen Schwierigkeit von Aufgaben, der mathematischen Leistungsfähigkeit von Schülerinnen und Schülern, dem Geschlecht und den Anforderungen der im Unterricht gestellten Aufgaben stehen.
Vor dem Hintergrund der dem deutschen Mathematikunterricht nachgesagten Kalkül- beziehungsweise Fertigkeitsorientierung (Baumert et al., 2001, S. 296; Granzer & Walther, 2008, S. 9) und den damit einhergehenden Stärken deutscher Schülerinnen und Schüler im Bereich von Routineaufgaben und Schwächen im Bereich von Aufgaben mit höheren kognitiven Anforderungen (Grassmann et al., 2014, S. 11; Reiss & Hammer, 2013, S. 82; Schütte, 2008, S. 41) wurde zudem die Verteilung der im Rahmen der Untersuchung gewonnenen, schriftlich fixierten geometrischen Schulbuch- und Unterrichtsaufgaben auf die drei Anforderungsbereiche analysiert.
Durch die Betrachtung geometrischer Aufgaben konnte stichprobenartig der quantitative Geometrieanteil in den Schulbüchern und im Unterricht der vierten Jahrgangsstufe ermittelt werden, um so den Forschungsstand zum Stellenwert des Geometrieunterrichts (Maier, 1999; Backe-Neuwald, 2000; Roick, Gölitz & Hasselhorn, 2004) zu aktualisieren beziehungsweise zu ergänzen.
Leaf litter breakdown is a fundamental process in aquatic ecosystems, being mainly mediated by decomposer-detritivore systems that are composed of microbial decomposers and leaf-shredding, detritivorous invertebrates. The ecological integrity of these systems can, however, be disturbed, amongst others, by chemical stressors. Fungicides might pose a particular risk as they can have negative effects on the involved microbial decomposers but may also affect shredders via both waterborne toxicity and their diet; the latter by toxic effects due to dietary exposure as a result of fungicides’ accumulation on leaf material and by negatively affecting fungal leaf decomposers, on which shredders’ nutrition heavily relies. The primary aim of this thesis was therefore to provide an in-depth assessment of the ecotoxicological implications of fungicides in a model decomposer-detritivore system using a tiered experimental approach to investigate (1) waterborne toxicity in a model shredder, i.e., Gammarus fossarum, (2) structural and functional implications in leaf-associated microbial communities, and (3) the relative importance of waterborne and diet-related effects for the model shredder.
Additionally, knowledge gaps were tackled that were related to potential differences in the ecotoxicological impact of inorganic (also authorized for organic farming in large parts of the world) and organic fungicides, the mixture toxicity of these substances, the field-relevance of their effects, and the appropriateness of current environmental risk assessment (ERA).
In the course of this thesis, major differences in the effects of inorganic and organic fungicides on the model decomposer-detritivore system were uncovered; e.g., the palatability of leaves for G. fossarum was increased by inorganic fungicides but deteriorated by organic substances. Furthermore, non-additive action of fungicides was observed, rendering mixture effects of these substances hardly predictable. While the relative importance of the waterborne and diet-related effect pathway for the model shredder seems to depend on the fungicide group and the exposure concentration, it was demonstrated that neither path must be ignored due to additive action. Finally, it was shown that effects can be expected at field-relevant fungicide levels and that current ERA may provide insufficient protection for decomposer-detritivore systems. To safeguard aquatic ecosystem functioning, this thesis thus recommends including leaf-associated microbial communities and long-term feeding studies using detritus feeders in ERA testing schemes, and identifies several knowledge gaps whose filling seems mandatory to develop further reasonable refinements for fungicide ERA.