Memristive Bauelemente für neuronale Schaltungen

The present post-doctoral thesis covers 14 original publications, which result from my work as research assistant between 2011 and 2015 at the Institute of electrical engineering at the technical faculty of the Christian-Albrecht university at Kiel. During this time my research work was strongly guided by the question how to understand memory and learning in brains and how we can build up non-biological systems, which function similar to those. In particular, I focused on the usage of new non-volatile memory technologies and electronic circuits for neuromorphic systems. Thus, the development of non-volatile devices and electronic circuits as well as biological models based on those devices is at the heart of this post-doctoral thesis

The Rectal Gland in Relation to the Osmoregulatory Mechanisms of Marine and Freshwater Elasmobranchs

The rectal gland of elasmobranchs secretes large quantities of electrolytes and is of primary importance in the osmoregulatory mechanisms of these animals (Burger and Hess, 1960; Burger, 1962). Analogously, various organs of other vertebrates are also known to be involved in salt secretion (Schmidt-Nielsen, 1965; Bonting, 1970; Bentley, 1971). In general, active ion transport is the basis of this phenomenon; in any case, it requires the presence of structural devices, morphologically and chemically well defined, and of metabolic capabilities which, taken singly, are not specific, but collectively are consistent with active ion transport and salt secretion

Subsidence and thermal history of an inverted Late Jurassic-Early Cretaceous extensional basin (Cameros, North-central Spain) affected by very low- to low-grade metamorphism.

The Cameros Basin (North Spain) is a Late Jurassic-Early Cretaceous extensional basin, which was inverted during the Cenozoic. It underwent a remarkable thermal evolution, as indicated by the record of anomalous high temperatures in its deposits. In this work the subsidence and thermal history of the basin is reconstructed, using subsidence analysis and 2D thermal modeling. Tectonic subsidence curves provide evidence of the occurrence of two rapid subsidence phases during the syn-extensional stage. In the first phase (Tithonian-Early Berriasian), the largest accommodation space was formed in the central sector of the basin, whereas in the second (Early Barremian-Early Albian), it was formed in the northern sector. These rapid subsidence phases could correspond to relevant tectonic events affecting the Iberian Plate at that time. By distinguishing between the initial and thermal subsidence and defining their relative magnitudes, Royden's (1986) method was used to estimate the heat flow at the end of the extensional stage. A maximum heat flow of 60-65 mW/m2 is estimated, implying only a minor thermal disturbance associated with extension. In contrast with these data, very high vitrinite reflectance, anomalously distributed in some case with respect to the typical depth-vitrinite reflectance relation, was measured in the central-northern sector of the basin. Burial and thermal data are used to construct a 2D thermal basin model, to elucidate the role of the processes involved in sediment heating. Calibration of the thermal model with the vitrinite reflectance (%Ro) and fluid inclusion (FI) data indicates that in the central and northern sectors of the basin, an extra heat source, other than a typical rift, is required to explain the observed thermal anomalies. The distribution of the %Ro and FI values in these sectors suggests that the high temperatures and their distribution are related to the circulation of hot fluids. Hot fluids were attributed to the hydrothermal metamorphic events affecting the area during the early post-extensional and inversion stages of the basin

Evolution of an intra-plate rift basin: the Latest Jurassic-Early Cretaceous Cameros Basin (Northwest Iberian Ranges, North Spain)

Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

Protein traffic is an intracellular target in alcohol toxicity

Eukaryotic cells comprise a set of organelles, surrounded by membranes with a unique composition, which is maintained by a complex synthesis and transport system. Cells also synthesize the proteins destined for secretion. Together, these processes are known as the secretory pathway or exocytosis. In addition, many molecules can be internalized by cells through a process called endocytosis. Chronic and acute alcohol (ethanol) exposure alters the secretion of different essential products, such as hormones, neurotransmitters and others in a variety of cells, including central nervous system cells. This effect could be due to a range of mechanisms, including alcohol-induced alterations in the different steps involved in intracellular transport, such as glycosylation and vesicular transport along cytoskeleton elements. Moreover, alcohol consumption during pregnancy disrupts developmental processes in the central nervous system. No single mechanism has proved sufficient to account for these effects, and multiple factors are likely involved. One such mechanism indicates that ethanol also perturbs protein trafficking. The purpose of this review is to summarize our understanding of how ethanol exposure alters the trafficking of proteins in different cell systems, especially in central nervous system cells (neurons and astrocytes) in adult and developing brains

Modelización de la evolución sedimentaria y térmica de una cuenca extensional intraplaca (Cuenca de Cameros): aplicación a la prospección de hidrocarburos

Tesis inédita presentada en la Universidad complutense de Madrid, Facultad de Ciencias Geológicas, Departamento de Petrología y Geoquímica, leída 02-10-2014Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEunpu

Quantifying Multiple Erosion Events in the Distal Sector of the Northern Alpine Foreland Basin (North-Eastern Switzerland), by Combining Basin Thermal Modelling with Vitrinite Reflectance and Apatite Fission Track Data

This work quantifies the amount of erosion associated with the Cretaceous and Miocene erosional unconformities recognised in the distal part of the Northern Alpine Foreland Basin (NAFB), north-eastern Switzerland. To achieve this goal, the basin thermal modelling approach is applied, calibrated by two different sets of data collected in previous studies: vitrinite reflectance (%Ro) and the temperature estimated from apatite fission tracks (AFT) data modelling. The novelty of this approach is the possibility to constrain the timing and magnitude of multiple erosion events by integrating thermal modelling with thermochronologic data. Combining these two methods allows the erosional events to be separated which would not be possible using only irreversible paleothermometers, such as vitrinite reflectance data. Two scenarios were tested, based on the data of two published thermochronology studies. For the Cretaceous unconformity, similar results are obtained for the two scenarios, both indicating that the deposition and the subsequent complete erosion of Lower Cretaceous deposits, in the order of 500–1300 m, depending on the area, are necessary, in order to attain the temperatures estimated by the thermal history modelling of AFT data. Thus, a depositional hiatus for this period is not likely. For the Miocene-Quaternary unconformity, the magnitude of erosion calculated for the two scenarios differs by 300–1400 m, depending on the AFT data considered. The two scenarios lead to a different evaluation of the subsidence and uplift rate of the study area, thus to a different interpretation of the tectono-stratigraphic evolution of this distal sector of the NAFB

Tectonic and climatic control on the Late Messinian sedimentary evolution of the Nijar Basin Nijar Basin (Betic Cordillera, Southern Spain)

The Late Messinian fill of the Nijar Basin (Betic Cordillera, southeastern Spain) mainly consists ofclastic deposits of the Feos Formation that at basin margins rest unconformably above the primaryevaporites of the Yesares Formation, the local equivalent of the Mediterranean Lower Gypsum. TheFeos Fm. records the upward transition towards non-marine environments before the abrupt returnto fully marine conditions at the base of the Pliocene. The Feos Fm. is clearly two-phase, with ‘lower’and ‘upper’ members, which exhibit substantial differences in terms of facies, thickness, depositionaltrends and cyclical organization. These members record two distinct sedimentary and tectonic stagesof Nijar Basin infilling. A high-resolution, physical-stratigraphic framework is proposed based onkey beds and stratigraphic cyclicity and patterns that differ largely from those of most previouslypublished studies. The predominant influence on stratigraphic cyclicity is interpreted to be precessionallydriven climate changes, allowing their correlation to the Late Messinian astronomicallycalibrated chronostratigraphic framework. Detailed correlations suggest a phase of enhanced tectonicactivity, possibly related to the Serrata-Carboneras strike-slip fault zone, during the first stage(‘lower’ member), resulting in a strongly articulated topography with structural lows and highscontrolling sediment thickness and facies variation. Tectonic activity decreased during the secondstage (‘upper’ member), which is characterized by (1) a progressively dampened and homogenized,(2) overall relative base-level rise and (3) gradual establishment of hypohaline environments. Faciescharacteristics, overall stacking patterns and depositional trends of the Feos Fm. are analogous withuppermost Messinian successions of the Northern Apennines, Piedmont Basin and Calabria. Despiteminor differences related to the local geodynamic setting, these basins experienced a common LateMessinian history that supports the development of a single, large Mediterranean water bodycharacterized by high-frequency, climatically-driven changes in sediment flux and base-level