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For a comprehensive understanding of evolutionary processes and for providing reliable prognoses about the future consequences of environmental change, it is essential to reveal the genetic basis underlying adaptive responses. The importance of this goal increases in light of ongoing climate change, which confronts organisms worldwide with new selection pressures and requires rapid evolutionary change to avoid local extinction. Thereby, freshwater ectotherms like daphnids are particularly threatened. Unraveling the genetic basis of local adaptation is complicated by the interplay of forces affecting patterns of genetic divergence among populations. Due to their key position in freshwater communities, cyclic parthenogenetic mode of reproduction and resting propagules (which form biological archives), daphnids are particularly suited for this purpose.
The aim of this thesis was to assess the impact of local thermal selection on the Daphnia longispina complex and to reveal the underlying genetic loci. Therefore, I compared genetic differentiation among populations containing Daphnia galeata, Daphnia longispina and their interspecific hybrids across time, space, and species boundaries. I revealed strongly contrasting patterns of genetic differentiation between selectively neutral and functional candidate gene markers, between the two species, and among samples from different lakes, suggesting (together with a correlation with habitat temperatures) local thermal selection acting on candidate gene TRY5F and indicating adaptive introgression. To reveal the candidate genes’ impact on fitness, I performed association analyses among data on genotypes and phenotypic traits of D. galeata clones from seven populations. The tests revealed a general temperature effect as well as inter-population differences in phenotypic traits and imply a possible contribution of the candidate genes to life-history traits. Finally, utilizing a combined population transcriptomic and reverse ecology approach, I introduced a methodology with a wide range of applications in evolutionary biology and revealed that local thermal selection was probably a minor force in shaping sequence and gene expression divergence among four D. galeata populations, but contributed to sequence divergence among two populations. I identified many transcripts possibly under selection or contributing strongly to population divergence, a large amount thereof putatively under local thermal selection, and showed that genetic and gene expression variation is not depleted specifically in temperature-related candidate genes.
In conclusion, I detected signs of local adaptation in the D. longispina complex across space, time, and species barriers. Populations and species remained genetically divergent, although increased gene flow possibly contributed, together with genotypes recruited from the resting egg bank, to the maintenance of standing genetic variation. Further work is required to accurately determine the influence of introgression and the effects of candidate genes on individual fitness. While I found no evidence suggesting a response to intense local thermal selection, the high resilience and adaptive potential regarding environmental change I observed suggest positive future prospects for the populations of the D. longispina complex. However, overall, due to the continuing environmental degradation, daphnids and other aquatic invertebrates remain vulnerable and threatened.
Wir analysieren versionsbasierte Softwareprojekte, um den Entwicklern API- und Domänen-Wissen zuzuordnen. Genauer gesagt analysieren wir die einzelnen Commits in einem Repository in Hinblick auf die API-Nutzung. Auf dieser Grundlage können wir APIs (oder Teile davon) den Entwicklern zuordnen und dadurch auf die API-Erfahrung der Entwickler schließen. Im transitiven Schluss können wir auf Domänen-Erfahrung schließen, da jeder API eine Programmierdomäne zugewiesen wird.
The thesis at hand evaluates Open Source Business Process Management (BPM) Systems in the context of the R4eGov1 Project. The provision of concepts and tools to support and enable interoperability in pan-European networks of pubic administrations is one of the major objectives that R4eGov is aiming at. Thereby a strong focus lies on the interoperability of cross-organizational processes from the viewpoint of modeling, execution and monitoring. BPM can increase the effectiveness and efficiency of cross-organizational processes by restructuring them towards the needs of the entities involved. BPM is dependent on BPM systems that combine technologies of process modeling, business process analysis and execution along with their integration into adequate runtime environments and rule engines. The evaluation that is performed within the thesis investigates how far BPM systems can support several requirements of interoperability that have been developed by the R4eGov project. It also targets at analyzing those BPM system according to generic requirements on BPM and software tools. The investigation is build upon common BPM theories and standards for modeling business processes. It describes the origin and interdependencies of BPM and Workflow Management (WfM), highlighting similarities and differences from the technological and historical perspective. Moreover, it introduces web service standards and technologies that are used to build service-oriented architectures allowing greater flexibility in BPM. In addition the thesis introduces methods and best practices to evaluate software tools. It contains an evaluation framework for BPM tools that has been based on the software product evaluation standard ISO/IEC 14598. The evaluation framework comprises the definition of an R4eGov scenario and a catalogue of criteria for evaluating a set of selected Open Source BPM systems. The definition of the catalogue of criteria is build upon generic requirements on BPM systems and those that are specifically to R4eGov. The chosen methods and the core elements of the evaluation framework will be applied to the selected BPM systems Intalio BPMS,NetBeans IDE, and JBoss jBPM. Finally the results of the applied R4eGov scenario and of the applied catalogue of criteria are being discussed by highlighting individual strengths and weaknesses of the systems.
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.
Im Rahmen dieser Bachelorarbeit wurde ein Back-Office für die elektronische Version des Europäischen Schadensberichtes erstellt. Es wurde bereits in anderen Arbeiten ein mobiler Client, welcher auf einem Windows Mobile Handy läuft, sowie ein Polizei Client erstellt. Diese greifen auf das Back-Office zu, um Daten, wie z.B. die Autodaten (Automarke, der Typ, das Baujahr und Bilder eines 3D-Modells des Autos) zu einem bestimmten Kennzeichen oder die Personendaten des jeweiligen Autobesitzers zu erhalten. Der mobile Client sendet zudem die Unfallakte an das Back-Office, damit die Daten über einen Unfall in diesem abgespeichert und weiter bearbeitet werden können. Ziel der Arbeit war es ein erweiterbares, modulares System zu entwickeln, welches später um weitere Module ergänzt werden kann, um neue Funktionen bereitstellen zu können. Diese Module können jeweils beliebige Daten in einer Datenbank abspeichern und diese von der Datenbank auch wieder abfragen, sowie verändern, ohne dass das relationale Schema der Datenbank verändert werden muss.
Die vorliegende Dissertation beschäftigt sich mit den Chancen und Restriktionen, denen Parteien im Wahlkampf auf supranationaler Ebene der EU begegnen. Mittels kommunikationswissenschaftlicher Konzepte des Agenda-Settings (Fokus: Medien) und Agenda-Buildings (Fokus: Parteien) wird anhand des Wahlkampfs zur Wahl des Europäischen Parlaments (EP) 2014 erstens analysiert, inwieweit nationale politische Parteien die EU als Thema auf ihre Agenda setzen und ob etablierte Parteien so zu einer Normalisierung des EU-Wahlkampfs beitragen können. Zweitens wird untersucht, ob Parteien einen strukturellen Vorteil haben, die mediale Agenda auch auf supranationaler Ebene im Wahlkampf beeinflussen zu können, also mit EU-fokussierter Wahlkampfkommunikation in den Medien punkten können. Drittens wird geprüft, ob sich Parteien durch die Ablehnung der EU-Integration und der damit verbundenen, konflikthaften Kommunikation einen Vorteil für die Sichtbarkeit ihrer Kampagnen verschaffen können. Viertens und abschließend wird erforscht, ob Agenda-Building die Rangfolge spezifischer politischer Themenfelder auf der medialen Agenda im europäischen Kontext beeinflussen kann.
Die Analysen zeigen erstens, dass ein europapolitischer Fokus der Wahlkampfkommunikation nicht mehr nur auf Seiten der kleinen (euroskeptischen) Parteien zu finden ist. Verfolgen die Parteien einen europapolitischen Fokus in ihrer Wahlkampfkommunikation, haben sie zweitens gute Chancen, in der Medienberichterstattung präsent zu sein. Drittens stellt sich ein negativer Tenor der Parteienkommunikation nicht als ausschlaggebend für die Sichtbarkeit der Parteien im Wahlkampf heraus. Eine klare Positionierung auf politischen Sachfragen bereitet Parteien viertens auch auf die Restriktionen der weiteren Ausbildung einer europäischen Themenagenda vor, da die Verschiebung in der Wichtigkeit von Themen zuerst von den Medien erfasst wird, die Kampagnenkommunikation folgt erst darauf. Die Arbeit schließt nach einer Diskussion dieser Ergebnisse mit einer Einschätzung der Analyselimitationen und einem Ausblick auf weitere Forschungsansätze.
Invasive species often have a significant impact on the biodiversity of ecosystems and the species native to it. One of the worst invaders worldwide is Aphanomyces astaci, the causative agent of the crayfish plague, an often fatal disease to crayfish species not native to North America. Aphanomyces astaci originates from North America and was introduced to Europe in the midst of the 19th century. Since then, it spread throughout Europe diminishing the European crayfish populations. The overall aim of this thesis was to evaluate the threat that A. astaci still poses to European crayfish species more than 150 years after its introduction to Europe. In the first part of the thesis, crayfish specimens, which are available in the German pet trade, were tested for infections with A. astaci. Around 13% of the tested crayfish were clearly infected with A. astaci. The study demonstrated the potential danger the pet trade poses for biodiversity through the import of alien species and their potential pathogens, in general. In the second part of the thesis, the A. astaci infection prevalence of crayfish species in wild populations in Europe was tested. While the stone crayfish, Austropotamobius torrentium, showed high susceptibility to different haplogroups of A. astaci, the narrow-clawed crayfish, Astacus leptodactylus, was able to survive infections, even by haplogroup B, which is considered to be highly virulent. In the last part of the thesis, A. astaci was traced back to its original distribution area of North America. While the crayfish plague never had such a devastating effect on crayfish in North America as it had in Europe, the reasons for the success of invasive crayfish within North America are not yet fully understood. It is possible that A. astaci increases the invasion success of some crayfish species. Several populations of the rusty crayfish, Orconectes rusticus, in the Midwest of North America were confirmed to be infected with A. astaci and a new genotype was identified, possibly indicating that each crayfish host is vector of a unique A. astaci genotype, even in North America. Overall, the present thesis provides evidence that A. astaci is still a major threat to the crayfish species indigenous to Europe. Crayfish mass mortalities still occur in susceptible crayfish species like A. torrentium even 150 years after the first introduction of A. astaci. While there are some indications for increased resistances through processes of co-evolution, the continuous introduction of crayfish species to Europe threatens to cause new outbreaks of the crayfish plague through the parallel introduction of new, highly virulent A. astaci strains.
In dieser Arbeit präsentieren wir Methoden zum Schätzen von Kamerabewegungen einer RGB-D-Kamera in sechs Freiheitsgraden und dem Erstellen von 3D-Karten. Als erstes werden die RGB- und Tiefendaten registriert und synchronisiert. Nach der Vorverarbeitung extrahieren wir FAST-Merkmale in zwei aufeinander folgenden Bildern. Daraus wird eine Korrespondenzmenge erstellt und Ausreißer werden herausgefiltert. Anschließend projizieren wir die Korrespondenzmenge in 3D, um die Bewegung aus 3D-3D-Korrespondezen mittels Least-Squares zu bestimmen. Weiterhin präsentieren wir Methoden, um 3D-Karten aus Bewegungsschätzungen und RGB-D-Daten zu erstellen. Dafür benutzen wir das OctoMap-Framework und erstellen wahlweise auch inkrementelle Karten aus Punktewolken. Anschließend evaluieren wir das System mit dem weit verbreiteten RGB-D-Benchmark.
In the last years, the public interest in epidemiology and mathematical modeling of disease spread has increased - mainly caused by the COVID-19 pandemic, which has emphasized the urgent need for accurate and timely modelling of disease transmission. However, even prior to that, mathematical modelling has been used for describing the dynamics and spread of infectious diseases, which is vital for developing effective interventions and controls, e.g., for vaccination campaigns and social restrictions like lockdowns. The forecasts and evaluations provided by these models influence political actions and shape the measures implemented to contain the virus.
This research contributes to the understanding and control of disease spread, specifically for Dengue fever and COVID-19, making use of mathematical models and various data analysis techniques. The mathematical foundations of epidemiological modelling, as well as several concepts for spatio-temporal diffusion like ordinary differential equation (ODE) models, are presented, as well as an originally human-vector model for Dengue fever, and the standard (SEIR)-model (with the potential inclusion of an equation for deceased persons), which are suited for the description of COVID-19. Additionally, multi-compartment models, fractional diffusion models, partial differential equations (PDE) models, and integro-differential models are used to describe spatial propagation of the diseases.
We will make use of different optimization techniques to adapt the models to medical data and estimate the relevant parameters or finding optimal control techniques for containing diseases using both Metropolis and Lagrangian methods. Reasonable estimates for the unknown parameters are found, especially in initial stages of pandemics, when little to no information is available and the majority of the population has not got in contact with the disease. The longer a disease is present, the more complex the modelling gets and more things (vaccination, different types, etc.) appear and reduce the estimation and prediction quality of the mathematical models.
While it is possible to create highly complex models with numerous equations and parameters, such an approach presents several challenges, including difficulties in comparing and evaluating data, increased risk of overfitting, and reduced generalizability. Therefore, we will also consider criteria for model selection based on fit and complexity as well as the sensitivity of the model with respect to specific parameters. This also gives valuable information on which political interventions should be more emphasized for possible variations of parameter values.
Furthermore, the presented models, particularly the optimization using the Metropolis algorithm for parameter estimation, are compared with other established methods. The quality of model calculation, as well as computational effort and applicability, play a role in this comparison. Additionally, the spatial integro-differential model is compared with an established agent-based model. Since the macroscopic results align very well, the computationally faster integro-differential model can now be used as a proxy for the slower and non-traditionally optimizable agent-based model, e.g., in order to find an apt control strategy.
Environmental processes transforming inorganic nanoparticles: implications on aquatic invertebrates
(2020)
Engineered inorganic nanoparticles (EINPs) are produced and utilized on a large scale and will end up in surface waters. Once in surface waters, EINPs are subjected to transformations induced by environmental processes altering the particles’ fate and inherent toxicity. UV irradiation of photoactive EINPs is defined as one effect-inducing pathway, leading to the formation of reactive oxygen species (ROS), increasing EINP toxicity by exerting oxidative stress in aquatic life. Simultaneously, UV irradiation of photoactive EINP alters the toxicity of co-occurring micropollutants (e.g. pesticides) by affecting their degradation. The presence of natural organic matter (NOM) reduces the agglomeration and sedimentation of EINPs, extending the exposure of pelagic species, while delaying the exposure of benthic species living in and on the sediment, which is suggested as final sink for EINPs. However, the joint impact of NOM and UV irradiation on EINP-induced toxicity, but also EINP-induced degradation of micropollutants, and the resulting risk for aquatic biota, is poorly understood. Although potential effects of EINPs on benthic species are increasingly investigated, the importance of exposure pathways (waterborne or dietary) is unclear, along with the reciprocal pathway of EINPs, i.e. the transport back from aquatic to terrestrial ecosystems. Therefore, this thesis investigates: (i) how the presence of NOM affects the UV-induced toxicity of the model EINP titanium dioxide (nTiO2) on the pelagic organism Daphnia magna, (ii) to which extent UV irradiation of nTiO2 in the presence and absence of NOM modifies the toxicity of six selected pesticides in D. magna, (iii) potential exposure pathway dependent effects of nTiO2 and silver (nAg) EINPs on the benthic organism Gammarus fossarum, and (iv) the transport of nTiO2 and gold EINPs (nAu) via the merolimnic aquatic insect Chaetopteryx villosa back to terrestrial ecosystems. nTiO2 toxicity in D. magna increased up to 280-fold in the presence of UV light, and was mitigated by NOM up to 12-fold. Depending on the pesticide, UV irradiation of nTiO2 reduced but also enhanced pesticide toxicity, by (i) more efficient pesticide degradation, and presumably (ii) formation of toxic by-products, respectively. Likewise, NOM reduced and increased pesticide toxicity, induced by (i) protection of D. magna against locally acting ROS, and (ii) mitigation of pesticide degradation, respectively. Gammarus’ energy assimilation was significantly affected by both EINPs, however, with distinct variation in direction and pathway dependence between nTiO2 and nAg. EINP presence delayed C. villosa emergence by up to 30 days, and revealed up to 40% reduced lipid reserves, while the organisms carried substantial amounts of nAu (~1.5 ng/mg), and nTiO2 (up to 2.7 ng/mg). This thesis shows, that moving test conditions of EINPs towards a more field-relevant approach, meaningfully modifies the risk of EINPs for aquatic organisms. Thereby, more efforts need to be made to understand the relative importance of EINP exposure pathways, especially since a transferability between different types of EINPs may not be given. When considering typically applied risk assessment factors, adverse effects on aquatic systems might already be expected at currently predicted environmental EINP concentrations in the low ng-µg/L range.