@phdthesis{Kaempf2015, author = {K{\"a}mpf, Lucas}, title = {Extreme events in geoarchives}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-85961}, school = {Universit{\"a}t Potsdam}, pages = {xii, 94}, year = {2015}, abstract = {A main limitation in the field of flood hydrology is the short time period covered by instrumental flood time series, rarely exceeding more than 50 to 100 years. However, climate variability acts on short to millennial time scales and identifying causal linkages to extreme hydrological events requires longer datasets. To extend instrumental flood time series back in time, natural geoarchives are increasingly explored as flood recorders. Therefore, annually laminated (varved) lake sediments seem to be the most suitable archives since (i) lake basins act as natural sediment traps in the landscape continuously recording land surface processes including floods and (ii) individual flood events are preserved as detrital layers intercalated in the varved sediment sequence and can be dated with seasonal precision by varve counting. The main goal of this thesis is to improve the understanding about hydrological and sedimentological processes leading to the formation of detrital flood layers and therewith to contribute to an improved interpretation of lake sediments as natural flood archives. This goal was achieved in two ways: first, by comparing detrital layers in sediments of two dissimilar peri-Alpine lakes, Lago Maggiore in Northern Italy and Mondsee in Upper Austria, with local instrumental flood data and, second, by tracking detrital layer formation during floods by a combined hydro-sedimentary monitoring network at Lake Mondsee spanning from the rain fall to the deposition of detrital sediment at the lake floor. Successions of sub-millimetre to 17 mm thick detrital layers were detected in sub-recent lake sediments of the Pallanza Basin in the western part of Lago Maggiore (23 detrital layers) and Lake Mondsee (23 detrital layers) by combining microfacies and high-resolution micro X-ray fluorescence scanning techniques (µ-XRF). The detrital layer records were dated by detailed intra-basin correlation to a previously dated core sequence in Lago Maggiore and varve counting in Mondsee. The intra-basin correlation of detrital layers between five sediment cores in Lago Maggiore and 13 sediment cores in Mondsee allowed distinguishing river runoff events from local erosion. Moreover, characteristic spatial distribution patterns of detrital flood layers revealed different depositional processes in the two dissimilar lakes, underflows in Lago Maggiore as well as under- and interflows in Mondsee. Comparisons with runoff data of the main tributary streams, the Toce River at Lago Maggiore and the Griesler Ache at Mondsee, revealed empirical runoff thresholds above which the deposition of a detrital layer becomes likely. Whereas this threshold is the same for the whole Pallanza Basin in Lago Maggiore (600 m3s-1 daily runoff), it varies within Lake Mondsee. At proximal locations close to the river inflow detrital layer deposition requires floods exceeding a daily runoff of 40 m3s-1, whereas at a location 2 km more distal an hourly runoff of 80 m3s-1 and at least 2 days with runoff above 40 m3s-1 are necessary. A relation between the thickness of individual deposits and runoff amplitude of the triggering events is apparent for both lakes but is obviously further influenced by variable influx and lake internal distribution of detrital sediment. To investigate processes of flood layer formation in lake sediments, hydro-sedimentary dynamics in Lake Mondsee and its main tributary stream, Griesler Ache, were monitored from January 2011 to December 2013. Precipitation, discharge and turbidity were recorded continuously at the rivers outlet to the lake and compared to sediment fluxes trapped close to the lake bottom on a basis of three to twelve days and on a monthly basis in three different water depths at two locations in the lake basin, in a distance of 0.9 (proximal) and 2.8 km (distal) to the Griesler Ache inflow. Within the three-year observation period, 26 river floods of different amplitude (10-110 m3s-1) were recorded resulting in variable sediment fluxes to the lake (4-760 g m-2d-1). Vertical and lateral variations in flood-related sedimentation during the largest floods indicate that interflows are the main processes of lake internal sediment transport in Lake Mondsee. The comparison of hydrological and sedimentological data revealed (i) a rapid sedimentation within three days after the peak runoff in the proximal and within six to ten days in the distal lake basin, (ii) empirical runoff thresholds for triggering sediment flux at the lake floor increasing from the proximal (20 m3s-1) to the distal lake basin (30 m3s-1) and (iii) factors controlling the amount of detrital sediment deposition at a certain location in the lake basin. The total influx of detrital sediment is mainly driven by runoff amplitude, catchment sediment availability and episodic sediment input by local sediment sources. A further role plays the lake internal sediment distribution which is not the same for each event but is favoured by flood duration and the existence of a thermocline and, therewith, the season in which a flood occurred. In summary, the studies reveal a high sensitivity of lake sediments to flood events of different intensity. Certain runoff amplitudes are required to supply enough detrital material to form a visible detrital layer at the lake floor. Reasonable are positive feedback mechanisms between rainfall, runoff, erosion, fluvial sediment transport capacity and lake internal sediment distribution. Therefore, runoff thresholds for detrital layer formation are site-specific due to different lake-catchment characteristics. However, the studies also reveal that flood amplitude is not the only control for the amount of deposited sediment at a certain location in the lake basin even for the strongest flood events. The sediment deposition is rather influenced by a complex interaction of catchment and in-lake processes. This means that the coring location within a lake basin strongly determines the significance of a flood layer record. Moreover, the results show that while lake sediments provide ideal archives for reconstructing flood frequencies, the reconstruction of flood amplitudes is a more complex issue and requires detailed knowledge about relevant catchment and in-lake sediment transport and depositional processes.}, language = {en} } @phdthesis{Papendiek2015, author = {Papendiek, Franka}, title = {Fodder legumes for Green Biorefineries}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-87198}, school = {Universit{\"a}t Potsdam}, pages = {XI, 111}, year = {2015}, abstract = {Peak oil is forcing our society to shift from fossil to renewable resources. However, such renewable resources are also scarce, and they too must be used in the most efficient and sustainable way possible. Biorefining is a concept that represents both resource efficiency and sustainability. This approach initiates a cascade use, which means food and feed production before material use, and an energy-related use at the end of the value-added chain. However, sustainability should already start in the fields, on the agricultural side, where the industrially-used biomass is produced. Therefore, the aim of my doctoral thesis is to analyse the sustainable feedstock supply for biorefineries. In contrast to most studies on biorefineries, I focus on the sustainable provision of feedstock and not on the bioengineering processing of whatever feedstock is available. Grasslands provide a high biomass potential. They are often inefficiently used, so a new utilisation concept based on the biorefining approach can increase the added value from grasslands. Fodder legumes from temporary and permanent grasslands were chosen for this study. Previous research shows that they are a promising feedstock for industrial uses, and their positive environmental impact is an important byproduct to promote sustainable agricultural production systems. Green Biorefineries are a class of biorefineries that use fresh green biomass, such as grasses or fodder legumes, as feedstock. After fractionation, an organic solution (press juice) forms; this is used for the production of organic acids, chemicals and extracts, as well as fertilisers. A fibre component (press cake) is also created to produce feed, biomaterials and biogas. This thesis examines a specific value chain, using alfalfa and clover/grass as feedstock and generating lactic acid and one type of cattle feed from it. The research question is if biomass production needs to be adapted for the utilisation of fodder legumes in the Green Biorefinery approach. I have attempted to give a holistic analysis of cultivation, processing and utilisation of two specific grassland crops. Field trials with alfalfa and clover/grass at different study sites were carried out to obtain information on biomass quality and quantity depending on the crop, study site and harvest time. The fresh biomass was fractionated with a screw press and the composition of press juices and cakes was analysed. Fermentation experiments took place to determine the usability of press juices for lactic acid production. The harvest time is not of high importance for the quality of press juices as a fermentation medium. For permanent grasslands, late cuts, often needed for reasons of nature conservation, are possible without a major influence on feedstock quality. The press cakes were silaged for feed-value determination. Following evidence that both intermediate products are suitable feedstocks in the Green Biorefinery approach, I developed a cost-benefit analysis, comparing different production scenarios on a farm. Two standard crop rotations for Brandenburg, producing either only market crops or market crops and fodder legumes for ruminant feed production, were compared to a system that uses the cultivated fodder legumes for the Green Biorefinery value chain instead of only feed production. Timely processing of the raw material is important to maintain quality for industrial uses, so on-site processing at the farm is assumed in Green Biorefinery scenario. As a result, more added value stays in the rural area. Two farm sizes, common for many European regions, were chosen to examine the influence of scale. The cost site of farmers has also been analysed in detail to assess which farm characteristics make production of press juices for biochemical industries viable. Results show that for large farm sizes in particular, the potential profits are high. Additionally, the wider spectrum of marketable products generates new sources of income for farmers. The holistic analysis of the supply chain provides evidence that the cultivation processes for fodder legumes do not need to be adapted for use in Green Biorefineries. In fact, the new utilisation approach even widens the cultivation and processing spectrum and can increase economic viability of fodder legume production in conventional farming.}, language = {en} } @phdthesis{Sander2015, author = {Sander, Andreas Alexander Christoph}, title = {Radiatively driven winds of hot stars}, school = {Universit{\"a}t Potsdam}, pages = {153}, year = {2015}, language = {en} } @phdthesis{Bendadani2015, author = {Bendadani, Carolin}, title = {1-Methylpyren: Biotransformation und Gentoxizit{\"a}t}, school = {Universit{\"a}t Potsdam}, pages = {188}, year = {2015}, language = {en} } @phdthesis{Herde2015, author = {Herde, Antje}, title = {Individual differences and seasonal variation in behaviour}, school = {Universit{\"a}t Potsdam}, pages = {111}, year = {2015}, language = {en} } @phdthesis{Baumeier2015, author = {Baumeier, Christian}, title = {Dietary and Pharmacological Strategies for the Prevention and Treatment of Type 2 Diabetes in a Diabetes-Susceptible Mouse Model}, school = {Universit{\"a}t Potsdam}, pages = {148}, year = {2015}, language = {en} } @phdthesis{Arabi2015, author = {Arabi, Fayezeh}, title = {Functional characterization of Sulfur Deficiency Induced genes, SDI1 and SDI2, in Arabidopsis thaliana}, school = {Universit{\"a}t Potsdam}, pages = {97}, year = {2015}, language = {en} } @phdthesis{Prandi2015, author = {Prandi, Simone}, title = {Characterization of the expression and function of bitter taste receptor genes in gastrointestinal tissues}, school = {Universit{\"a}t Potsdam}, pages = {165}, year = {2015}, language = {en} } @phdthesis{Golle2015, author = {Golle, Kathleen}, title = {Physical fitness in school-aged children}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-85949}, school = {Universit{\"a}t Potsdam}, pages = {xi, 147, xii}, year = {2015}, abstract = {Physical fitness is an important marker of health that enables people to carry out activities of daily living with vigour and alertness but without undue fatigue and with sufficient reserve to enjoy active leisure pursuits and to meet unforeseen emergencies. Especially, due to scientific findings that the onset of civilization diseases (e.g., obesity, cardiovascular disease) begins in childhood and that physical fitness tracks (at least) into young adulthood, the regular monitoring and promotion of physical fitness in children is risen up to a public health issue. In relation to the evaluation of a child's physical fitness over time (i.e., development) the use of longitudinally-based percentile values is of particular interest due to their underlined dedication of true physical fitness development within subjects (i.e., individual changes in timing and tempo of growth and maturation). Besides its genetic determination (e.g., sex, body height), physical fitness is influenced by factors that refer to children's environment and behaviour. For instance, disparities in physical fitness according to children's living area are frequently reported concerning the fact that living in rural areas as compared to urban areas seems to be more favourable for children's physical fitness. In addition, cross-sectional studies found higher fitness values in children participating in sports clubs as compared to non-participants. However, up to date, the observed associations between both (i.e., living area and sports club participating) and children's physical fitness are unresolved concerning a long-term effect. In addition, social inequality as determined by the socioeconomic status (SES) extends through many areas of children's life. While evidence indicates that the SES is inversely related to various indices of child's daily life and behaviour like educational success, nutritional habits, and sedentary- and physical activity behaviour, a potential relationship between child's physical fitness and the SES is hardly investigated and indicated inconsistent results. The present thesis addressed three objectives: (1) to generate physical fitness percentiles for 9- to 12- year-old boys and girls using a longitudinal approach and to analyse the age- and sex-specific development of physical fitness, (2) to investigate the long-term effect of living area and sports club participation on physical fitness in third- to sixth-grade primary school students, and (3) to examine associations between the SES and physical fitness in a large and representative (i.e., for a German federal state) sample of third grade primary school students. Methods (i/ii) Healthy third graders were followed over four consecutive years (up to grade 6), including annually assessment of physical fitness and parental questionnaire (i.e., status of sports club participation and living area). Six tests were conducted to estimate various components of physical fitness: speed (50-m sprint test), upper body muscular power (1-kg ball push test), lower body muscular power (triple hop test), flexibility (stand-and-reach test), agility (star agility run test), and cardiorespiratory fitness (CRF) (9-min run test). (iii) Within a cross-sectional study (i.e., third objective), physical fitness of third graders was assessed by six physical fitness tests including: speed (20-m sprint test), upper body muscular power (1-kg ball push test), lower body muscular power (standing long jump [SLJ] test), flexibility (stand-and-reach test), agility (star agility run test), and CRF (6-min run test). By means of questionnaire, students reported their status of organized sports participation (OSP). Results (i) With respect to percentiles of physical fitness development, test performances increased in boys and girls from age 9 to 12, except for males' flexibility (i.e., stable performance over time). Girls revealed significantly better performance in flexibility, whereas boys scored significantly higher in the remaining physical fitness tests. In girls as compared to boys, physical fitness development was slightly faster for upper body muscular power but substantially faster for flexibility. Generated physical fitness percentile curves indicated a timed and capacity-specific physical fitness development (curvilinear) for upper body muscular power, agility, and CRF. (ii) Concerning the effect of living area and sports club participation on physical fitness development, children living in urban areas showed a significantly faster performance development in physical fitness components of upper and lower body muscular power as compared to peers from rural areas. The same direction was noted as a trend in CRF. Additionally, children that regularly participated in a sports club, when compared to those that not continuously participated in a sports club demonstrated a significantly faster performance development in lower body muscular power. A trend of faster performance development in sports club participants occurred in CRF too. (iii) Regarding the association of SES with physical fitness, the percentage of third graders that achieved a high physical fitness level in lower body muscular power and CRF was significantly higher in students attending schools in communities with high SES as compared to middle and low SES, irrespective of sex. Similar, students from the high SES-group performed significantly better in lower body muscular power and CRF than students from the middle and/or the low SES-group. Conclusion (i) The generated percentile values provide an objective tool to estimate childrenʼs physical fitness within the frame of physical education (e.g., age- and sex-specific grading of motor performance) and further to detect children with specific fitness characteristics (low fit or high fit) that may be indicative for the necessity of preventive health promotion or long term athlete development. (ii) It is essential to consider variables of different domains (e.g., environment and behavior) in order to improve knowledge of potential factors which influence physical fitness during childhood. In this regard, the present thesis provide a first input to clarify the causality of living area and sports club participation on physical fitness development in school-aged children. Living in urban areas as well as a regular participation in sports clubs positively affected children´s physical fitness development (i.e., muscular power and CRF). Herein, sports club participation seems to be a key factor within the relationship between living area and physical fitness. (iii) The findings of the present thesis imply that attending schools in communities with high SES refers to better performance in specific physical fitness test items (i.e., muscular power, CRF) in third graders. Extra-curricular physical education classes may represent an important equalizing factor for physical activity opportunities in children of different SES backgrounds. In regard to strong evidence of a positive relationship between physical fitness - in particular muscular fitness/ CRF - and health, more emphasis should be laid on establishing sports clubs and extra-curricular physical education classes as an easy and attractive means to promote fitness-, and hence health- enhancing daily physical activity for all children (i.e. public health approach).}, language = {en} } @phdthesis{Ramisch2015, author = {Ramisch, Arne}, title = {Lake system development on the northern Tibetan Plateau during the last ~ 12 ka}, school = {Universit{\"a}t Potsdam}, pages = {122}, year = {2015}, language = {en} }