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Two of the most controversial issues concerning the late Cenozoic evolution of the Andean orogen are the timing of uplift of the intraorogenic Puna plateau and its eastern border, the Eastern Cordillera, and ensuing changes in climatic and surface-process conditions in the intermontane basins of the NW-Argentine Andes. The Eastern Cordillera separates the internally drained, arid Puna from semi-arid intermontane basins and the humid sectors of the Andean broken foreland and the Subandean fold-and-thrust belt to the east. With elevations between 4,000 and 6,000 m the eastern flanks of the Andes form an efficient orographic barrier with westward-increasing elevation and asymmetric rainfall distribution and amount with respect to easterly moisture-bearing winds. This is mirrored by pronounced gradients in the efficiency of surface processes that erode and re-distribute sediment from the uplifting ranges. Although the overall pattern of deformation and uplift in this sector of the southern central Andes shows an eastward migration of deformation, a well-developed deformation front does not exist and uplift and associated erosion and sedimentary processes are highly disparate in space and time. In addition, periodic deformation within intermontane basins, and continued diachronous foreland uplifts associated with the reactivation of inherited basement structures furthermore make a rigorous assessment of the spatiotemporal uplift patterns difficult.
This thesis focuses on the tectonic evolution of the Eastern Cordillera of NW Argentina, the depositional history of its intermontane sedimentary basins, and the regional topographic evolution of the eastern flank of the Puna Plateau. The intermontane basins of the Eastern Cordillera and the adjacent morphotectonic provinces of the Sierras Pampeanas and the Santa Bárbara System are akin to reverse fault bounded, filled, and partly coalesced sedimentary basins of the Puna Plateau. In contrast to the Puna basins, however, which still form intact morphologic entities, repeated deformation, erosion, and re-filling have impacted the basins in the Eastern Cordillera. This has resulted in a rich stratigraphy of repeated basin fills, but many of these basins have retained vestiges of their early depositional history that may reach back in time when these areas were still part of a contiguous and undeformed foreland basin. Fortunately, these strata also contain abundant volcanic ashes that are not only important horizons to decipher tectono-sedimentary events through U-Pb geochronology and geochemical correlation, but they also represent terrestrial recorders of the hydrogen-isotope composition of ancient meteoric waters that can be compared to the isotopic composition of modern meteoric water. The ash horizons are thus unique recorders of past environmental conditions and lend themselves to tracking the development of rainfall barriers and tectonically forced climate and environmental change through time.
U-Pb zircon geochronology and paleocurrent reconstructions of conglomerate sequences in the Humahuaca Basin of the Eastern Cordillera at 23.5° S suggest that the basin was an integral part of a largely unrestricted depositional system until 4.2 Ma, which subsequently became progressively decoupled from the foreland by range uplifts to the east that forced easterly moisture-bearing winds to precipitate in increasingly eastward locations. Multiple cycles of severed hydrological conditions and drainage re-capture are identified together with these processes that were associated with basin filling and sediment evacuation, respectively. Moreover, systematic relationships among faults, regional unconformities and deformed landforms reveal a general pattern of intra-basin deformation that appears to be linked with basin-internal deformation during or subsequent to episodes of large-scale sediment removal. Some of these observations are supported by variations in the hydrogen stable isotope composition of volcanic glass from the Neogene to Quaternary sedimentary record, which can be related to spatiotemporal changes in topography and associated orographic effects. δDg values in the basin strata reveal two main trends associated with surface uplift in the catchment area between 6.0 and 3.5 Ma and the onset of semiarid conditions in the basin following the attainment of threshold elevations for effective orographic barriers to the east after 3.5 Ma. The disruption of sediment supply from western sources after 4.2 Ma and subsequent hinterland aridification, moreover, emphasize the possibility that these processes were related to lateral orogenic growth of the adjacent Puna Plateau. As a result of the hinterland aridification the regions in the orogen interior have been characterized by an inefficient fluvial system, which in turn has helped maintaining internal drainage conditions, sediment storage, and relief reduction within high-elevation basins.
The diachronous nature of basin formation and impacts on the fluvial system in the adjacent broken foreland is underscored by the results of detailed sediment provenance and paleocurrent analyses, as well as U-Pb zircon geochronology in the Lerma and Metán basins at ca. 25° S. This is particularly demonstrated by the isolated uplift of the Metán range at ~10 Ma, which is more than 50 km away from the presently active orogenic front along the eastern Puna margin and the Eastern Cordillera to the west. At about 5 Ma, Puna-sourced sediments disappear from the foreland record, documenting further range uplifts in the Eastern Cordillera and hydrological isolation of the neighboring Angastaco Basin from the foreland. Finally, during the late Pliocene and Quaternary, deformation has been accommodated across the entire foreland and is still active. To elucidate the interactions between tectonically controlled changes in elevation and their impact on atmospheric circulation processes in this region, this thesis provides additional, temporally well-constrained hydrogen stable isotope results of volcanic glass samples from the broken foreland, including the Angastaco Basin, and other intermontane basins farther south. The results suggest similar elevations of intermontane basins and the foreland sectors prior to ca. 7 Ma. In case of the Angastaco Basin the region was affected by km-scale surface uplift of the basin. A comparison with coeval isotope data collected from sedimentary sequences in the Puna plateau explains rapid shifts in the intermontane δDg record and supports the notion of recurring phases of enhanced deep convection during the Pliocene, and thus climatic conditions during the middle to late Pliocene similar to the present day.
Combined, field-based and isotope geochemical methods used in this study of the NW-Argentine Andes have thus helped to gain insight into the systematics, rate changes, interactions, and temporal characteristics among tectonically controlled deformation patterns, the build-up of topography impacting atmospheric processes, the distribution of rainfall, and resulting surface processes in a tectonically active mountain belt. Ultimately, this information is essential for a better understanding of the style and the rates at which non-collisional mountain belts evolve, including the development orogenic plateaus and their bordering flanks. The results presented in this study emphasize the importance of stable isotope records for paleoaltimetric and paleoenvironmental studies in mountain belts and furnishes important data for a rigorous interpretation of such records.
Anthropogenic activities have transformed the Earth's environment, not only on local level, but on the planetary-scale causing global change. Besides industrialization, agriculture is a major driver of global change. This change in turn impairs the agriculture sector, reducing crop yields namely due to soil degradation, water scarcity, and climate change. However, this is a more complex issue than it appears. Crop yields can be increased by use of agrochemicals and fertilizers which are mainly produced by fossil energy. This is important to meet the increasing food demand driven by global demographic change, which is further accelerated by changes in regional lifestyles. In this dissertation, we attempt to address this complex problem exploring agricultural potential globally but on a local scale. For this, we considered the influence of lifestyle changes (dietary patterns) as well as technological progress and their effects on climate change, mainly greenhouse gas (GHG) emissions. Furthermore, we examined options for optimizing crop yields in the current cultivated land with the current cropping patterns by closing yield gaps. Using this, we investigated in a five-minute resolution the extent to which food demand can be met locally, and/or by regional and/or global trade. Globally, food consumption habits are shifting towards calorie rich diets. Due to dietary shifts combined with population growth, the global food demand is expected to increase by 60-110% between 2005 and 2050. Hence, one of the challenges to global sustainability is to meet the growing food demand, while at the same time, reducing agricultural inputs and environmental consequences. In order to address the above problem, we used several freely available datasets and applied multiple interconnected analytical approaches that include artificial neural network, scenario analysis, data aggregation and harmonization, downscaling algorithm, and cross-scale analysis.
Globally, we identified sixteen dietary patterns between 1961 and 2007 with food intakes ranging from 1,870 to 3,400 kcal/cap/day. These dietary patterns also reflected changing dietary habits to meat rich diets worldwide. Due to the large share of animal products, very high calorie diets that are common in the developed world, exhibit high total per capita emissions of 3.7-6.1 kg CO2eq./day. This is higher than total per capita emissions of 1.4-4.5 kg CO2eq./day associated with low and moderate calorie diets that are common in developing countries. Currently, 40% of the global crop calories are fed to livestock and the feed calorie use is four times the produced animal calories. However, these values vary from less than 1 kcal to greater 10 kcal around the world. On the local and national scale, we found that the local and national food production could meet demand of 1.9 and 4.4 billion people in 2000, respectively. However, 1 billion people from Asia and Africa require intercontinental agricultural trade to meet their food demand. Nevertheless, these regions can become food self-sufficient by closing yield gaps that require location specific inputs and agricultural management strategies. Such strategies include: fertilizers, pesticides, soil and land improvement, management targeted on mitigating climate induced yield variability, and improving market accessibility. However, closing yield gaps in particular requires global N-fertilizer application to increase by 45-73%, P2O5 by 22-46%, and K2O by 2-3 times compare to 2010. Considering population growth, we found that the global agricultural GHG emissions will approach 7 Gt CO2eq./yr by 2050, while the global livestock feed demand will remain similar to 2000. This changes tremendously when diet shifts are also taken into account, resulting in GHG emissions of 20 Gt CO2eq./yr and an increase of 1.3 times in the crop-based feed demand between 2000 and 2050. However, when population growth, diet shifts, and technological progress by 2050 were considered, GHG emissions can be reduced to 14 Gt CO2eq./yr and the feed demand to nearly 1.8 times compare to that in 2000. Additionally, our findings shows that based on the progress made in closing yield gaps, the number of people depending on international trade can vary between 1.5 and 6 billion by 2050. In medium term, this requires additional fossil energy. Furthermore, climate change, affecting crop yields, will increase the need for international agricultural trade by 4% to 16%.
In summary, three general conclusions are drawn from this dissertation. First, changing dietary patterns will significantly increase crop demand, agricultural GHG emissions, and international food trade in the future when compared to population growth only. Second, such increments can be reduced by technology transfer and technological progress that will enhance crop yields, decrease agricultural emission intensities, and increase livestock feed conversion efficiencies. Moreover, international trade dependency can be lowered by consuming local and regional food products, by producing diverse types of food, and by closing yield gaps. Third, location specific inputs and management options are required to close yield gaps. Sustainability of such inputs and management largely depends on which options are chosen and how they are implemented. However, while every cultivated land may not need to attain its potential yields to enable food security, closing yield gaps only may not be enough to achieve food self-sufficiency in some regions. Hence, a combination of sustainable implementations of agricultural intensification, expansion, and trade as well as shifting dietary habits towards a lower share of animal products is required to feed the growing population.
Development of geophysical methods to characterize methane hydrate reservoirs on a laboratory scale
(2015)
Gas hydrates are crystalline solids composed of water and gas molecules. They are stable at elevated pressure and low temperatures. Therefore, natural gas hydrate deposits occur at continental margins, permafrost areas, deep lakes, and deep inland seas. During hydrate formation, the water molecules rearrange to form cavities which host gas molecules. Due to the high pressure during hydrate formation, significant amounts of gas can be stored in hydrate structures. The water-gas ratio hereby can reach up to 1:172 at 0°C and atmospheric pressure. Natural gas hydrates predominantly contain methane. Because methane constitutes both a fuel and a greenhouse gas, gas hydrates are a potential energy resource as well as a potential source for greenhouse gas.
This study investigates the physical properties of methane hydrate bearing sediments on a laboratory scale. To do so, an electrical resistivity tomography (ERT) array was developed and mounted in a large reservoir simulator (LARS). For the first time, the ERT array was applied to hydrate saturated sediment samples under controlled temperature, pressure, and hydrate saturation conditions on a laboratory scale. Typically, the pore space of (marine) sediments is filled with electrically well conductive brine. Because hydrates constitute an electrical isolator, significant contrasts regarding the electrical properties of the pore space emerge during hydrate formation and dissociation. Frequent measurements during hydrate formation experiments permit the recordings of the spatial resistivity distribution inside LARS. Those data sets are used as input for a new data processing routine which transfers the spatial resistivity distribution into the spatial distribution of hydrate saturation. Thus, the changes of local hydrate saturation can be monitored with respect to space and time.
This study shows that the developed tomography yielded good data quality and resolved even small amounts of hydrate saturation inside the sediment sample. The conversion algorithm transforming the spatial resistivity distribution into local hydrate saturation values yielded the best results using the Archie-var-phi relation. This approach considers the increasing hydrate phase as part of the sediment frame, metaphorically reducing the sample’s porosity. In addition, the tomographical measurements showed that fast lab based hydrate formation processes cause small crystallites to form which tend to recrystallize.
Furthermore, hydrate dissociation experiments via depressurization were conducted in order to mimic the 2007/2008 Mallik field trial. It was observed that some patterns in gas and water flow could be reproduced, even though some setup related limitations arose.
In two additional long-term experiments the feasibility and performance of CO2-CH4 hydrate exchange reactions were studied in LARS. The tomographical system was used to monitor the spatial hydrate distribution during the hydrate formation stage. During the subsequent CO2 injection, the tomographical array allowed to follow the CO2 migration front inside the sediment sample and helped to identify the CO2 breakthrough.
During the last two decades, instability training devices have become a popular means in athletic training and rehabilitation of mimicking unstable surfaces during movements like vertical jumps. Of note, under unstable conditions, trunk muscles seem to have a stabilizing function during exercise to facilitate the transfer of torques and angular momentum between the lower and upper extremities. The present thesis addresses the acute effects of surface instability on performance during jump-landing tasks. Additionally, the long-term effects (i.e., training) of surface instability were examined with a focus on the role of the trunk in athletic performance/physical fitness.
Healthy adolescent, and young adult subjects participated in three cross-sectional and one longitudinal study, respectively. Performance in jump-landing tasks on stable and unstable surfaces was assessed by means of a ground reaction force plate. Trunk muscle strength (TMS) was determined using an isokinetic device or the Bourban TMS test. Physical fitness was quantified by standing long jump, sprint, stand-and-reach, jumping sideways, Emery balance, and Y balance test on stable surfaces. In addition, activity of selected trunk and leg muscles and lower limb kinematics were recorded during jump-landing tasks.
When performing jump-landing tasks on unstable compared to stable surfaces, jump performance and leg muscle activity were significantly lower. Moreover, significantly smaller knee flexion angles and higher knee valgus angles were observed when jumping and landing on unstable compared to stable conditions and in women compared to men. Significant but small associations were found between behavioral and neuromuscular data, irrespective of surface condition. Core strength training on stable as well as on unstable surfaces significantly improved TMS, balance and coordination.
The findings of the present thesis imply that stable rather than unstable surfaces provide sufficient training stimuli during jump exercises (i.e., plyometrics). Additionally, knee motion strategy during plyometrics appears to be modified by surface instability and sex. Of note, irrespective of surface condition, trunk muscles only play a minor role for leg muscle performance/activity during jump exercises. Moreover, when implemented in strength training programs (i.e., core strength training), there is no advantage in using instability training devices compared to stable surfaces in terms of enhancement of athletic performance.
The high-latitudinal thermospheric processes driven by the solar wind and Interplanetary Magnetic Field (IMF) interaction with the Earth magnetosphere are highly variable parts of the complex dynamic plasma environment, which represent the coupled Magnetosphere – Ionosphere – Thermosphere (MIT) system. The solar wind and IMF interactions transfer energy to the MIT system via reconnection processes at the magnetopause. The Field Aligned Currents (FACs) constitute the energetic links between the magnetosphere and the Earth ionosphere. The MIT system depends on the highly variable solar wind conditions, in particular on changes of the strength and orientation of the IMF.
In my thesis, I perform an investigation on the physical background of the complex MIT system using the global physical - numerical, three-dimensional, time-dependent and self-consistent Upper Atmosphere Model (UAM). This model describes the thermosphere, ionosphere, plasmasphere and inner magnetosphere as well as the electrodynamics of the coupled MIT system for the altitudinal range from 80 (60) km up to the 15 Earth radii.
In the present study, I developed and investigated several variants of the high-latitudinal electrodynamic coupling by including the IMF dependence of FACs into the UAM model. For testing, the various variants were applied to simulations of the coupled MIT system for different seasons, geomagnetic activities, various solar wind and IMF conditions. Additionally, these variants of the theoretical model with the IMF dependence were compared with global empirical models. The modelling results for the most important thermospheric parameters like neutral wind and mass density were compared with satellite measurements. The variants of the UAM model with IMF dependence show a good agreement with the satellite observations. In comparison with the empirical models, the improved variants of the UAM model reproduce a more realistic meso-scale structures and dynamics of the coupled MIT system than the empirical models, in particular at high latitudes. The new configurations of the UAM model with IMF dependence contribute to the improvement of space weather prediction.
Welfare states and policies have changed greatly over the past decades, mostly characterized by retrenchments in terms of government spending or in terms of restricted access to certain benefits. In the area of family policies, however, a lot of countries have simultaneously expanded provisions and transfers for families. Bringing together the macro analysis of policy variation and household income changes on the micro-level, the main research question of the dissertation is to what extent economic consequences following separation and divorce in families with children have changed between the 1980s and the 2000s in Germany and the United States. The second research question of the dissertation regards the differences in dissolution outcomes between married and cohabiting parents in Germany.
The dissertation thus aims to link institutional regulations of welfare states with the actual income situation of families. To achieve this, a research design was developed that has never been used for the analysis of the economic consequences of family dissolution. For this, the two longest running panel datasets, German Socio-economic Panel (GSOEP) and the US American Panel Study of Income Dynamics (PSID), have been used. The analytic strategy applied to estimate the effects of family dissolution on household income is a difference-in-difference design combined with coarsened exact matching (CEM).
To begin with, the dissertation confirmed many findings of previous research, for example regarding the gender differences in family dissolution outcomes. Mothers experience clearly higher relative income losses and consequently higher risks of poverty than fathers. This finding is universal, that is it holds for both countries, for all time periods observed, and for all measures of economic outcome that were employed. Another confirmed finding is the higher level of welfare state intervention in Germany compared to the United States.
The dissertation also revealed a number of novel findings. The results show that the expansion of family policies in Germany over time has not been accompanied by substantially decreasing income losses for mothers. Though income losses have slightly decreased over time, they have become more persistent during the years following family dissolution. The impact of the German welfare state has meanwhile been quite stable.
American mothers’ income losses took place on a slightly lower level than those of German mothers. Only during the 1980s their relative losses were clearly lower than those of German mothers. And also American mothers did not recover as much from their income losses during the 2000s than they used to during the 1980s. For them, the 1996 welfare reform brought a considerable decrease in welfare state support. Accordingly, the results for American mothers can certainly be described as a shift from public to private provision.
The general finding of previous studies that fathers do not have to suffer income losses, or if at all rather moderate ones compared to mothers, can be confirmed. Nevertheless, both German and US American fathers face a deterioration of the economic consequences of family dissolution over time. German fathers’ relative income changes are still positive though they have decreased over time. One reason for this decrease is the increasing loss of partner earnings following union dissolution. Also among American fathers, income gains still prevail in the year of family dissolution. Two years later, however, they have been facing income losses already since the 1980s which have furthermore increased considerably over time.
Zooming in on Germany, family dissolution outcomes by marital status show negligible differences between cohabiting and married mothers in disposable income, but considerable differences in losses of income before taxes and transfers. It is the impact of the welfare state that equalizes the differences in income losses between these two groups of mothers. For married mothers, losses are not as high in the year of event but they have difficulties to recover from these losses. Without the income buffering of the welfare state, married mothers would, three years after family dissolution, remain with relative income losses double as high as for cohabiting mothers.
Compared to mothers, differences between married and cohabiting fathers are visible in changes of income before as well as after taxes and transfers. The welfare state does not alter the difference between the two groups of fathers. With regard to both income concepts, cohabiting fathers fare worse than married fathers. Cohabiting fathers suffer moderate income losses of disposable income while married fathers experience moderate income gains. Accounting for support payments is decisive for fathers’ income changes. If these payments are not deducted from disposable income, both married and cohabiting fathers experience gains in disposable income following family dissolution.
Plant cell walls are complex structures that underpin plant growth and are widely exploited in diverse human activities thus placing them with a central importance in biology. Cell walls have been a prominent area of research for a long time, but the chemical complexity and diversity of cell walls not just between species, but also within plants, between cell-types, and between cell wall micro-domains pose several challenges. Progress accelerated several-fold in cell wall biology owing to advances in sequencing technology, aided soon thereafter by advances in omics and imaging technologies. This development provides additional perspectives of cell walls across a rapidly growing number of species, highlighting a myriad of architectures, compositions, and functions.
Furthermore, rather than the component centric view, integrative analysis of the different cell wall components across system-levels help to gain a more in-depth understanding of the structure and biosynthesis of the cell envelope and its interactions with the environment.
To this end, in this work three case studies are detailed, all pertaining to the integrative analysis of heterogeneous cell wall related data arising from different system-levels and analytical techniques. A detailed account of multiblock methods is provided and in particular canonical correlation and regression methods of data integration are discussed. In the first integrative analysis, by employing canonical correlation analysis - a multivariate statistical technique to study the association between two datasets - novel insight to the relationship between glycans and phenotypic traits is gained. In addition, sparse partial least squares regression approach that adapts Lasso penalization and allows for the selection of a subset of variables was employed. The second case study focuses on an integrative analysis of images obtained from different spectroscopic techniques. By employing yet another multiblock approach - multiple co-inertia analysis, insitu biochemical composition of cell walls from different cell-types is studied thereby highlighting the common and complementary parts of the two hyperspectral imaging techniques. Finally, the third integrative analysis facilitates gene expression analysis of the Arabidopsis root transcriptome and translatome for the identification of cell wall related genes and compare expression patterns of cell wall synthesis genes. The computational analysis considered correlation and variation of expression across cell-types at both system-levels, and also provides insight into the degree of co-regulatory relationships that are preserved between the two processes.
The integrative analysis of glycan data and phenotypic traits in cotton fibers using canonical methods led to the identification of specific polysaccharides which may play a major role during fiber development for the final fiber characteristics. Furthermore, this analysis provides a base for future studies on glycan arrays in case of developing cotton fibers. The integrative analysis of images from infrared and Raman spectroscopic approaches allowed the coupling of different analytical techniques to characterize complex biological material, thereby, representing various facets of their chemical properties. Moreover, the results from the co-inertia analysis demonstrated that the study was well adapted as it is relevant for coupling data tables in a symmetric way. Several indicators are proposed to investigate how the global and block scores are related. In addition, studying the root cells of \textit{Arabidopsis thaliana} allowed positing a novel pipeline to systematically investigate and integrate the different levels of information available at the global and single-cell level. The conducted analysis also confirms that previously identified key transcriptional activators of secondary cell wall development display highly conserved patterns of transcription and translation across the investigated cell-types. Moreover, the biological processes that display conserved and divergent patterns based on the cell-type-specific expression and translation levels are identified.
The dissertation proposes that the spread of photography and popular cinema in 19th- and 20th-century-India have shaped an aesthetic and affective code integral to the reading and interpretation of Indian English novels, particularly when they address photography and/or cinema film, as in the case of the four corpus texts. In analyzing the nexus between ‘real’ and ‘reel’, the dissertation shows how the texts address the reader as media consumer and virtual image projector. Furthermore, the study discusses the Indian English novel against the backdrop of the cultural and medial transformations of the 20th century to elaborate how these influenced the novel’s aesthetics. Drawing upon reception aesthetics, the author devises the concept of the ‘implied spectator’ to analyze the aesthetic impact of the novels’ images as visual textures.
No God in Sight (2005) by Altaf Tyrewala comprises of a string of 41 interior monologues, loosely connected through their narrators’ random encounters in Mumbai in the year 2000. Although marked by continuous perspective shifts, the text creates a sensation of acute immediacy. Here, the reader is addressed as implied spectator and is sutured into the narrated world like a film spectator ― an effect created through the use of continuity editing as a narrative technique.
Similarly, Ruchir Joshi’s The Last Jet Engine Laugh (2002) coll(oc)ates disparate narrative perspectives and explores photography as an artistic practice, historiographic recorder and epistemological tool. The narrative appears guided by the random viewing of old photographs by the protagonist and primary narrator, the photographer Paresh Bhatt. However, it is the photographic negative and the practice of superimposition that render this string of episodes and different perspectives narratively consequential and cosmologically meaningful. Photography thus marks the perfect symbiosis of autobiography and historiography.
Tabish Khair’s Filming. A Love Story (2007) immerses readers in the cine-aesthetic of 1930s and 40s Bombay film, the era in which the embedded plot is set. Plotline, central scenes and characters evoke the key films of Indian cinema history such as Satyajit Ray’s “Pather Panchali” or Raj Kapoor’s “Awara”. Ultimately, the text written as film dissolves the boundary between fiction and (narrated) reality, reel and real, thereby showing that the images of individual memory are inextricably intertwined with and shaped by collective memory. Ultimately, the reconstruction of the past as and through film(s) conquers trauma and endows the Partition of India as a historic experience of brutal contingency with meaning.
The Bioscope Man (Indrajit Hazra, 2008) is a picaresque narrative set in Calcutta - India’s cultural capital and birthplace of Indian cinema at the beginning of the 20th century. The autodiegetic narrator Abani Chatterjee relates his rise and fall as silent film star, alternating between the modes of tell and show. He is both autodiegetic narrator and spectator or perceiving consciousness, seeing himself in his manifold screen roles. Beyond his film roles however, the narrator remains a void. The marked psychoanalytical symbolism of the text is accentuated by repeated invocations of dark caves and the laterna magica. Here too, ‘reel life’ mirrors and foreshadows real life as Indian and Bengali history again interlace with private history. Abani Chatterjee thus emerges as a quintessentially modern man of no qualities who assumes definitive shape only in the lost reels of the films he starred in.
The final chapter argues that the static images and visual frames forwarded in the texts observe an integral psychological function: Premised upon linear perspective they imply a singular, static subjectivity appealing to the postmodern subject. In the corpus texts, the rise of digital technology in the 1990s thus appears not so much to have displaced older image repertories, practices and media techniques, than it has lent them greater visibility and appeal. Moreover, bricolage and pastiche emerge as cultural techniques which marked modernity from its inception. What the novels thus perpetuate is a media archeology not entirely servant to the poetics of the real. The permeable subject and the notion of the gaze as an active exchange as encapsulated in the concept of darshan - ideas informing all four texts - bespeak the resilience of a mythical universe continually re-instantiated in new technologies and uses. Eventually, the novels convey a sense of subalternity to a substantially Hindu nationalist history and historiography, the centrifugal force of which developed in the twentieth century and continues into the present.
The overarching goal of this dissertation is to provide a better understanding of the role of wind and water in shaping Earth’s Cenozoic orogenic plateaus - prominent high-elevation, low relief sectors in the interior of Cenozoic mountain belts. In particular, the feedbacks between surface uplift, the build-up of topography and ensuing changes in precipitation, erosion, and vegetation patterns are addressed in light of past and future climate change. Regionally, the study focuses on the two world’s largest plateaus, the Altiplano-Puna Plateau of the Andes and Tibetan Plateau, both characterized by average elevations of >4 km. Both plateaus feature high, deeply incised flanks with pronounced gradients in rainfall, vegetation, hydrology, and surface processes. These characteristics are rooted in the role of plateaus to act as efficient orographic barriers to rainfall and to force changes in atmospheric flow.
The thesis examines the complex topics of tectonic and climatic forcing of the surface-process regime on three different spatial and temporal scales: (1) bedrock wind-erosion rates are quantified in the arid Qaidam Basin of NW Tibet over millennial timescales using cosmogenic radionuclide dating; (2) present-day stable isotope composition in rainfall is examined across the south-central Andes in three transects between 22° S and 28° S; these data are modeled and assessed with remotely sensed rainfall data of the Tropical Rainfall Measuring Mission and the Moderate Resolution Imaging Spectroradiometer; (3) finally, a 2.5-km-long Mio-Pliocene sedimentary record of the intermontane Angastaco Basin (25°45’ S, 66°00’ W) is presented in the context of hydrogen and carbon compositions of molecular lipid biomarker, and oxygen and carbon isotopes obtained from pedogenic carbonates; these records are compared to other environmental proxies, including hydrated volcanic glass shards from volcanic ashes intercalated in the sedimentary strata.
There are few quantitative estimates of eolian bedrock-removal rates from arid, low relief landscapes. Wind-erosion rates from the western Qaidam Basin based on cosmogenic 10Be measurements document erosion rates between 0.05 to 0.4 mm/yr. This finding indicates that in arid environments with strong winds, hyperaridity, exposure of friable strata, and ongoing rock deformation and uplift, wind erosion can outpace fluvial erosion. Large eroded sediment volumes within the Qaidam Basin and coeval dust deposition on the Chinese Loess plateau, exemplify the importance of dust production within arid plateau environments for marine and terrestrial depositional processes, but also health issues and fertilization of soils.
In the south-central Andes, the analysis of 234 stream-water samples for oxygen and hydrogen reveals that areas experiencing deep convective storms do not show the commonly observed patterns of isotopic fractionation and the expected co-varying relationships between oxygen and hydrogen with increasing elevation. These convective storms are formed over semi-arid intermontane basins in the transition between the broken foreland of the Sierras Pampeanas, the Eastern Cordillera, and the Puna Plateau in the interior of the orogen. Here, convective rainfall dominates the precipitation budget and no systematic stable isotope-elevation relationship exists. Regions to the north, in the transition between the broken foreland and the Subandean foreland fold-and-thrust belt, the impact of convection is subdued, with lower degrees of storminess and a stronger expected isotope-elevation relationship. This finding of present-day fractionation trends of meteoric water is of great importance for paleoenvironmental studies in attempts to use stable isotope relationships in the reconstruction of paleoelevations.
The third part of the thesis focuses on the paleohydrological characteristics of the Mio-Pliocene (10-2 Ma) Angastaco Basin sedimentary record, which reveals far-reaching environmental changes during Andean uplift and orographic barrier formation. A precipitation- evapotranspiration record identifies the onset of a precipitation regime related to the South American Low Level Jet at this latitude after 9 Ma. Humid foreland conditions existed until 7 Ma, followed by orographic barrier uplift to the east of the present-day Angastaco Basin. This was superseded by rapid (~0.5 Myr) aridification in an intermontane basin, highlighting the effects of eastward-directed deformation. A transition in vegetation cover from a humid C3 forest ecosystem to semi-arid C4-dominated vegetation was coeval with continued basin uplift to modern elevations.
The relationship between nutrition and the development of chronic diseases including metabolic syndrome, diabetes mellitus, cancer and cardiovascular disease has been well studied. On the other hand, changes in the GH-IGF-1 axis in association with nutrition-related diseases have been reported. The interplay between GH, total IGF-1 and different inhibitory and stimulatory kinds of IGF-1 binding proteins (IGFBPs) results in IGF-1 bioactivity, the ability of IGF-1 to induce phosphorylation of its receptor and consequently its signaling. Moreover, IGF-1 bioactivity is sufficient to reflect any change in the GH-IGF-1 system. Accumulating evidence suggests that both of high protein diet, characterized by increased glucagon secretion, and insulin-induced hypoglycemia increase mortality rate and the mechanisms are unclear. However both of glucagon and insulin-induced hypoglycemia are potent stimuli of GH secretion. The aim of the current study was to identify the impact of glucagon and insulin-induced hypoglycemia on IGF-1 bioactivity as possible mechanisms. In a double-blind placebo-controlled study, glucagon was intramuscularly administrated in 13 type 1 diabetic patients (6 males /7 females; [BMI]: 24.8 ± 0.95 kg/m2), 11 obese subjects (OP; 5/ 6; 34.4 ± 1.7 kg/m2), and 13 healthy lean participants (LP; 6/ 7; 21.7 ± 0.6 kg/m2), whereas 12 obese subjects (OP; 6/ 6; 34.4 ± 1.7 kg/m2), and 13 healthy lean participants (LP; 6/ 7; 21.7 ± 0.6 kg/m2) performed insulin tolerance test in another double-blind placebo-controlled study and changes in GH, total IGF-1, IGF binding proteins (IGFBPs) and IGF-1 bioactivity, measured by the cell-based KIRA method, were investigated. In addition, the interaction between the metabolic hormones (glucagon and insulin) and the GH-IGF-1 system on the transcriptional level was studied using mouse primary hepatocytes. In this thesis, glucagon decreased IGF-1 bioactivity in humans independently of endogenous insulin levels, most likely through modulation of IGFBP-1 and-2 levels. The glucagon-induced reduction in IGF-1 bioactivity may represent a novel mechanism underlying the impact of glucagon on GH secretion and may explain the negative effect of high protein diet related to increased cardiovascular risk and mortality rate. In addition, insulin-induced hypoglycemia was correlated with a decrease in IGF-1 bioactivity through up-regulation of IGFBP-2. These results may refer to a possible and poorly explored mechanism explaining the strong association between hypoglycemia and increased cardiovascular mortality among diabetic patients.