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This thesis addresses the problem of terrain classification in unstructured outdoor environments. Terrain classification includes the detection of obstacles and passable areas as well as the analysis of ground surfaces. A 3D laser range finder is used as primary sensor for perceiving the surroundings of the robot. First of all, a grid structure is introduced for data reduction. The chosen data representation allows for multi-sensor integration, e.g., cameras for color and texture information or further laser range finders for improved data density. Subsequently, features are computed for each terrain cell within the grid. Classification is performedrnwith a Markov random field for context-sensitivity and to compensate for sensor noise and varying data density within the grid. A Gibbs sampler is used for optimization and is parallelized on the CPU and GPU in order to achieve real-time performance. Dynamic obstacles are detected and tracked using different state-of-the-art approaches. The resulting information - where other traffic participants move and are going to move to - is used to perform inference in regions where the terrain surface is partially or completely invisible for the sensors. Algorithms are tested and validated on different autonomous robot platforms and the evaluation is carried out with human-annotated ground truth maps of millions of measurements. The terrain classification approach of this thesis proved reliable in all real-time scenarios and domains and yielded new insights. Furthermore, if combined with a path planning algorithm, it enables full autonomy for all kinds of wheeled outdoor robots in natural outdoor environments.
Aquatic macrophytes can contribute to the retention of organic contaminants in streams, whereas knowledge on the dynamics and the interaction of the determining processes is very limited. The objective of the present study was thus to assess how aquatic macrophytes influence the distribution and the fate of organic contaminants in small vegetated streams. In a first study that was performed in vegetated stream mesocosms, the peak reductions of five compounds were significantly higher in four vegetated stream mesocosms compared to a stream mesocosm without vegetation. Compound specific sorption to macrophytes was determined, the mass retention in the vegetated streams, however, did not explain the relationship between the mitigation of contaminant peaks and macrophyte coverage. A subsequent mesocosm study revealed that the mitigation of peak concentrations in the stream mesocosms was governed by two fundamentally different processes: dispersion and sorption. Again, the reductions of the peak concentrations of three different compounds were in the same order of magnitude in a sparsely and a densely vegetated stream mesocosm, respectively, but higher compared to an unvegetated stream mesocosm. The mitigation of the peak reduction in the sparsely vegetated stream mesocosm was found to be fostered by longitudinal dispersion as a result of the spatial distribution of the macrophytes in the aqueous phase. The peak reduction attributable to longitudinal dispersion was, however, reduced in the densely vegetated stream mesocosm, which was compensated by compound-specific but time-limited and reversible sorption to macrophytes. The observations on the reversibility of sorption processes were subsequently confirmed by laboratory experiments. The experiments revealed that sorption to macrophytes lead to compound specific elimination from the aqueous phase during the presence of transient contaminant peaks in streams. After all, these sorption processes were found to be fully reversible, which results in the release of the primarily adsorbed compounds, once the concentrations in the aqueous phase starts to decrease. Nevertheless, the results of the present thesis demonstrate that the processes governing the mitigation of contaminant loads in streams are fundamentally different to those already described for non-flowing systems. In addition, the present thesis provides knowledge on how the interaction of macrophyte-induced processes in streams contributes to mitigate loads of organic contaminants and the related risk for aquatic environments.
Emotion regulation – an empirical investigation in female adolescents with nonsuicidal self- injury
(2015)
Nonsuicidal self-injury (NSSI) was included as a condition for further study in the DSM-5. Therefore, it is necessary to investigate the suggested diagnostic criteria and the clinical and psychological correlates. In order to provide an optimal treatment best tailored to the patients need, a clear differentiation between Borderline Personality Disorder (BPD) and NSSI is needed. The investigation of personality traits specific to patients with NSSI might be helpful for this differentiation. Furthermore, social difficulties can often be a trigger for NSSI. However, little is known about how adolescents with NSSI perceive social situations. Therefore, we examined how adolescents with NSSI process emotional expressions. A new emotion recognition paradigm (ERP) using colored and morphed facial expressions of happiness, anger, sadness, disgust and fear was developed and evaluated in a student sample, selected for being high (HSA) or low socially anxious (LSA). HSA showed a tendency towards impaired emotion recognition, and the paradigm demonstrated good construct validity.
For the main study, we investigated characteristics of NSSI, clinical and psychological correlates, personality traits and emotion recognition. We examined 57 adolescents with NSSI diagnosis, 12 adolescents with NSSI without impairment/distress and 14 adolescents with BPD, 32 clinical controls without NSSI, and 64 nonclinical controls. Participants were interviewed regarding mental disorders, filled out self-report questionnaires and participated in the ERP.
Results indicate that adolescents with NSSI experienced a higher level of impairment than clinical controls. There were similarities between adolescents with NSSI and adolescents with BPD, but also important differences. Adolescents with NSSI were characterized by specific personality traits such as high harm avoidance and novelty seeking compared to clinical controls. In adolescents with BPD, these personality traits were even more pronounced. No group differences in the recognition of facial expressions were found. Nonetheless compared to the control group, adolescents with NSSI rated the stimuli as significantly more unpleasant and arousing.
In conclusion, NSSI is a highly impairing disorder characterized by high comorbidity with various disorders and by specific personality traits, providing further evidence that NSSI should be handled as a distinct diagnostic entity. Consequently, the proposed DSM-5 diagnostic criteria for NSSI are useful and necessary.
Global crop production increased substantially in recent decades due to agricultural intensification and expansion and today agricultural areas occupy about 38% of Earth’s terrestrial surface - the largest use of land on the planet. However, current high-intensity agricultural practices fostered in the context of the Green Revolution led to serious consequences for the global environment. Pesticides, in particular, are highly biologically active substances that can threaten the ecological integrity of aquatic and terrestrial ecosystems. Although the global pesticide use increases steadily, our field-data based knowledge regarding exposure of non-target ecosystems such as surface waters is very restricted. Available studies have by now been limited to spatially restricted geographical areas or had rather specific objectives rendering the extrapolation to larger spatial scales questionable.
Consequently, this thesis evaluated based on four scientific publications the exposure, effects, and regulatory implications of particularly toxic insecticides` concentrations detected in global agricultural surface waters. FOCUS exposure modelling was used to characterise the highly specific insecticide exposure patterns and to analyse the resulting implications for both monitoring and risk assessment (publication I). Based on more than 200,000 scientific database entries, 838 peer-reviewed studies finally included, and more than 2,500 sites in 73 countries, the risks of agricultural insecticides to global surface waters were analysed by means of a comprehensive meta-analysis (publication II). This meta-analysis evaluated whether insecticide field concentrations exceed legally accepted regulatory threshold levels (RTLs) derived from official EU and US pesticide registration documents and, amongst others, how risks depend on insecticide development over time and stringency of environmental regulation. In addition, an in-depth analysis of the current EU pesticide regulations provided insights into the level of protection and field relevance of highly elaborated environmental regulatory risk assessment schemes (publications III and IV).
The results of this thesis show that insecticide surface water exposure is characterized by infrequent and highly transient concentration peaks of high ecotoxicological relevance. We thus argue in publication I that sampling based on regular intervals is inadequate for the detection of insecticide surface water concentrations and that traditional risk assessment concepts based on all insecticide concentrations including non-detects lead to severely biased results and critical underestimations of risks. Based on these considerations, publication II demonstrates that out of 11,300 measured insecticide concentrations (MICs; i.e., those actually detected and quantified), 52.4% (5,915 cases; 68.5%) exceeded the RTL for either water (RTLSW) or sediments. This indicates a substantial risk for the biological integrity of global water resources as additional analyses on pesticide effects in the field clearly evidence that the regional aquatic biodiversity is reduced by approximately 30% at pesticide concentrations equalling the RTLs. In addition, publication II shows that there is a complete lack of scientific monitoring data for ~90% of global cropland and that both the actual insecticide contamination of surface waters and the resulting ecological risks are most likely even greater due to, for example, inadequate sampling methods employed in the studies and the common occurrence of pesticide mixtures. A linear model analysis identified that RTLSW exceedances depend on the catchment size, sampling regime, sampling date, insecticide substance class, and stringency of countries` environmental regulations, as well as on the interactions of these factors. Importantly, the risks are significantly higher for newer-generation insecticides (i.e., pyrethroids) and are high even in countries with stringent environmental regulations. Regarding the latter, an analysis of the EU pesticide regulations revealed critical deficiencies and the lack of protectiveness and field-relevance for current presumed highly elaborated FOCUS exposure assessment (publication IV) and overall risk assessment schemes (publication III). Based on these findings, essential risk assessment amendments are proposed.
In essence, this thesis analyses the agriculture–environment linkages for pesticides at the global scale and it thereby contributes to a new research frontier in global ecotoxicology. The overall findings substantiate that agricultural insecticides are potential key drivers for the global freshwater biodiversity crisis and that the current regulatory risk assessment approaches for highly toxic anthropogenic chemicals fail to protect the global environment. This thesis provides an integrated view on the environmental side effects of global high-intensity agriculture and alerts that beside worldwide improvements to current pesticide regulations and agricultural pesticide application practices, the fundamental reformation of conventional agricultural systems is urgently needed to meet the twin challenges of providing sufficient food for a growing human population without destroying the ecological integrity of global ecosystems essential to human existence.
Diese Arbeit betrachtet das Thema Führung und Gesundheit und hat hierzu verschiedene Erkenntnisse der Literatur zusammengefasst, um diese von Führungskräften aus Wirtschaft und Polizei sowie von Personal- und Organisationsentwicklern bewerten zu lassen. Das Ziel war hierbei herauszufinden, ob die Führungskräfte und die Personal- und Organisationsentwickler das Thema als wichtig erachten, welche Hauptursachen sie für Fehlzeiten sehen und wie sie verschiedene Erkenntnisse der Literatur zum Gesundheitsmanagement einschätzen. Zusätzlich sollten sie bewerten, welche Maßnahmen sie als geeignet betrachten und welche Ressourcen notwendig sind, um die Mitarbeiter bei der Gesunderhaltung zu unterstützen. Schließlich sollten die Führungskräfte und die Personal- und Organisationsentwickler beurteilen, welcher Führungsstil als gesundheitsförderlich angesehen wird. Die Wirtschafts- und Polizeiführungskräfte sowie die Personal- und Organisationsentwickler erachten das Thema Gesundheit als wichtig und sehen es nicht nur als Modetrend an. Ihre Einschätzungen zu geeigneten Maßnahmen, die die Gesundheit der Mitarbeiter verbessern können, entsprechen überwiegend den aus der Literatur abgeleiteten Vorschlägen zur gesundheitsgerechten Führung. Die weitgehende Übereinstimmung der Sichtweisen in Forschung und Praxis legt nahe, dass die Erkenntnisse der Literatur zum Gesundheitsmanagement vermutlich von Praktikern als plausibel wahrgenommen werden.
In the new epoch of Anthropocene, global freshwater resources are experiencing extensive degradation from a multitude of stressors. Consequently, freshwater ecosystems are threatened by a considerable loss of biodiversity as well as substantial decrease in adequate and secured freshwater supply for human usage, not only on local scales, but also on regional to global scales. Large scale assessments of human and ecological impacts of freshwater degradation enable an integrated freshwater management as well as complement small scale approaches. Geographic information systems (GIS) and spatial statistics (SS) have shown considerable potential in ecological and ecotoxicological research to quantify stressor impacts on humans and ecological entitles, and disentangle the relationships between drivers and ecological entities on large scales through an integrated spatial-ecological approach. However, integration of GIS and SS with ecological and ecotoxicological models are scarce and hence the large scale spatial picture of the extent and magnitude of freshwater stressors as well as their human and ecological impacts is still opaque. This Ph.D. thesis contributes novel GIS and SS tools as well as adapts and advances available spatial models and integrates them with ecological models to enable large scale human and ecological impacts identification from freshwater degradation. The main aim was to identify and quantify the effects of stressors, i.e climate change and trace metals, on the freshwater assemblage structure and trait composition, and human health, respectively, on large scales, i.e. European and Asian freshwater networks. The thesis starts with an introduction to the conceptual framework and objectives (chapter 1). It proceeds with outlining two novel open-source algorithms for quantification of the magnitude and effects of catchment scale stressors (chapter 2). The algorithms, i.e. jointly called ATRIC, automatically select an accumulation threshold for stream network extraction from digital elevation models (DEM) by assuring the highest concordance between DEM-derived and traditionally mapped stream networks. Moreover, they delineate catchments and upstream riparian corridors for given stream sampling points after snapping them to the DEM-derived stream network. ATRIC showed similar or better performance than the available comparable algorithms, and is capable of processing large scale datasets. It enables an integrated and transboundary management of freshwater resources by quantifying the magnitude of effects of catchment scale stressors. Spatially shifting temporal points (SSTP), outlined in chapter 3, estimates pooled within-time series (PTS) variograms by spatializing temporal data points and shifting them. Data were pooled by ensuring consistency of spatial structure and temporal stationarity within a time series, while pooling sufficient number of data points and increasing data density for a reliable variogram estimation. SSTP estimated PTS variograms showed higher precision than the available method. The method enables regional scale stressors quantification by filling spatial data gaps integrating temporal information in data scarce regions. In chapter 4, responses of the assumed climate-associated traits from six grouping features to 35 bioclimatic indices for five insect orders were compared, their potential for changing distribution pattern under future climate change was evaluated and the most influential climatic aspects were identified (chapter 4). Traits of temperature preference grouping feature and the insect order Ephemeroptera exhibited the strongest response to climate as well as the highest potential for changing distribution pattern, while seasonal radiation and moisture were the most influential climatic aspects that may drive a change in insect distribution pattern. The results contribute to the trait based freshwater monitoring and change prediction. In chapter 5, the concentrations of 10 trace metals in the drinking water sources were predicted and were compared with guideline values. In more than 53% of the total area of Pakistan, inhabited by more than 74 million people, the drinking water was predicted to be at risk from multiple trace metal contamination. The results inform freshwater management by identifying potential hot spots. The last chapter (6) synthesizes the results and provides a comprehensive discussion on the four studies and on their relevance for freshwater resources conservation and management.
Placing questions before the material or after the material constitute different reading situations. To adapt to these reading situations, readers may apply appropriate reading strategies. Reading strategy caused by location of question has been intensively explored in the context of text comprehension. (1) However, there is still not enough knowledge about whether text plays the same role as pictures when readers apply different reading strategies. To answer this research question, three reading strategies are experimentally manipulated by displaying question before or after the blended text and picture materials: (a) Unguided processing with text and pictures and without the question. (b) Information gathering to answer the questions after the prior experience with text and pictures. (c) Comprehending text and pictures to solve the questions with the prior information of the questions. (2) Besides, it is arguable whether readers prefer text or pictures when the instructed questions are in different difficulty levels. (3) Furthermore, it is still uncertain whether students from higher school tier (Gymnasium) emphasize more on text or on pictures than students from lower school tier (Realschule). (4) Finally, it is rarely mentioned whether higher graders are more able to apply reading strategies in text processing and picture processing than lower graders.
Two experiments were undertaken to investigate the usage of text and pictures in the perspectives of task orientation, question difficulty, school and grade. For a 2x2(x2x2x2) mixed design adopting eye tracking method, participants were recruited from grade 5 (N = 72) and grade 8 (N = 72). In Experiment 1, thirty-six 5th graders were recruited from higher tier (Gymnasium) and thirty-six 5th graders were from lower tier (Realschule). In Experiment 2, thirty-six 8th graders were recruited from higher tier and thirty-six were from lower tier. They were supposed to comprehend the materials combining text and pictures and to answer the questions. A Tobii XL60 eye tracker recorded their eye movements and their answers to the questions. Eye tracking indicators were analyzed and reported, such as accumulated fixation duration, time to the first fixation and transitions between different Areas of Interest. The results reveal that students process text differently from pictures when they follow different reading strategies. (1) Consistent with Hypothesis 1, students mainly use text to construct their mental model in unguided spontaneous processing of text and pictures. They seem to mainly rely on the pictures as external representations when trying to answer questions after the prior experience with the material. They emphasize on both text and pictures when questions are presented before the material. (2) Inconsistent with Hypothesis 2, students are inclined to emphasize on text and on pictures as question difficulty increases. However, the increase of focus on pictures is more than on text when the presented question is difficult. (3) Different from Hypothesis 3, the current study discovers that higher tier students did not differ from lower tier students in text processing. Conversely, students from higher tier attend more to pictures than students from lower tier. (4) Differed from Hypothesis 4, 8th graders outperform 5th graders mainly in text processing. Only a subtle difference is found between 5th graders and 8th graders in picture processing.
To sum up, text processing differs from picture processing when applying different reading strategies. In line with the Integrative Model of Text and Picture Comprehension by Schnotz (2014), text is likely to play a major part in guiding the processing of meaning or general reading, whereas pictures are applied as external representations for information retrieval or selective reading. When question is difficulty, pictures are emphasized due to their advantages in visualizing the internal structure of information. Compared to lower tier students (poorer problem solvers), higher tier students (good problem solvers) are more capable of comprehending pictures rather than text. Eighth graders are more efficient than 5th graders in text processing rather than picture processing. It also suggests that in designing school curricula, more attention should be paid to students’ competence on picture comprehension or text-picture integration in the future.
Factors triggering the ecotoxicity of metal-based nanoparticles towards aquatic invertebrates
(2015)
Nanoparticles are produced and used in huge amounts increasing their probability to end up in surface waters. There, they are subject to environmentally driven modification processes. Consequently, aquatic life may be exposed to different nanoparticle agglomerate sizes, while after sedimentation benthic organisms are more likely to be affected.
However, most ecotoxicity studies with nanoparticles exclusively investigated implications of their characteristics (e.g. size) on pelagic organisms, ignoring environmentally modified nanoparticles. Therefore, a systematic assessment of factors triggering the fate and toxicity of nanoparticles under environmentally relevant conditions is needed. The present thesis, therefore, investigates the implications of nanoparticle related factors (i.e., inherent material-properties and nanoparticle characteristics) as well as environmental conditions towards the pelagic living organism Daphnia magna and the benthic species Gammarus fossarum. In detail, inert titanium dioxide (nTiO2) and ion-releasing silver nanoparticles (nAg), both of varying particle characteristics (e.g. initial size), were tested for their toxicity under different environmental conditions (e.g. ultraviolet-light (UV-light)).
The results indicate that the toxicity of nTiO2 and nAg is mainly determined by: their adsorption potential onto biota, and their fate in terms of reactive oxygen species or Ag+ ion release. Thus, inherent material-properties, nanoparticle characteristics and environmental conditions promoting or inhibiting these aspects revealed significant implications in the toxicity of nTiO2 and nAg towards daphnids.
Furthermore, the presence of ambient UV-light, for example, adversely affected gammarids at 0.20 mg nTiO2/L, while under darkness no effects occurred even at 5.00 mg nTiO2/L. Hence, the currently associated risk of nanoparticles might be underestimated if disregarding their interaction with environmental parameters
Die Basis für die Untersuchung bilden die theoretischen Erkenntnisse zur Transition und zum Fremdsprachenunterricht. In der Studie wurden saarländische Grundschullehrer und Gymnasiallehrer zu für den Fremdsprachenunterricht relevanten Aspekten befragt. Aus den Ergebnissen wurden Konsequenzen für die Bildungspolitik und die Unterrichtspraxis abgeleitet.
Modern agriculture is a dominant land use in Europe, although it has been associated with negative effects on biodiversity in agricultural landscapes. One species-rich insect group in agro-ecosystems is the Lepidoptera (moths and butterflies); however, the populations of a number of Lepidoptera species are currently declining. The aims of this thesis were to assess the amount and structure of field margins in agricultural landscapes, study the effects of realistic field margin input rates of agrochemicals (fertilizer and pesticides) on Lepidoptera, and provide information on moth pollination services.
In general, field margins are common semi-natural habitat elements in agro-ecosystems; however, data on the structure, size, and width of field margins is limited. An assessment in two German agricultural landscapes (4,000 ha each) demonstrated that many of the evaluated field margins were less than 3 m wide (Rhineland‐Palatinate: 85% of margin length; Brandenburg: 45% margin length). In Germany, risk mitigation measures (such as buffer zones) to reduce pesticide inputs to terrestrial non-crop habitats do not have to be established by farmers next to narrow field margins. Thus, narrow field margins receive inputs of agrochemicals, especially via overspray and spray drift. These field margins were used as a development habitat for caterpillars, but the mean abundance of caterpillars was 35 – 60% lower compared with that in meadows. Caterpillars were sensitive to realistic field margin input rates of insecticide (pyrethroid, lambda-cyhalothrin) in a field experiment as well as in laboratory experiments. Moreover, 40% fewer Hadena bicruris eggs were observed on Silene latifolia plants treated with this insecticide compared with control plants, and the flowers of these insecticide-treated plants were less likely to be pollinated by moths. In addition, realistic field margin input rates of herbicides can also affect Lepidoptera. Ranunculus acris L. plants treated with sublethal rates of a sulfonylurea herbicide were used as host plants for Mamestra brassicae L. caterpillars, which resulted in significantly lower caterpillar weights, increased time to pupation, and increased overall development time compared with caterpillars feeding on control plants. These results might have been caused by lower nutritional value of the herbicide-treated plants or increased concentrations of secondary metabolites involved in plant defense. Fertilizer applications slightly increased the caterpillar abundance in the field experiment. However, fertilizers reduce plant diversity in the long term and thus, most likely, also reduce caterpillar diversity.
Moths such as Noctuidae and Sphingidae have been observed to act as pollinators for numerous plant species, including a number of Orchidaceae and Caryophyllaceae. Although in temperate agro-ecosystems moths are less likely to act as the main pollinators for crops, they can pollinate non-crop plants in semi-natural habitats. Currently, the role of moths as pollinators appears to be underestimated, and long-term research focusing on ecosystems is necessary to address temporal fluctuations in their abundance and community composition.
Lepidoptera represent a diverse organism group in agricultural landscapes and fulfill essential ecosystem services, such as pollination. To better protect moths and butterflies, agrochemical inputs to (narrow) field margins habitats should be reduced, for example, via risk mitigation measures and agro-environmental schemes.