Parallel implementation of a robust optical flow technique

[EN] The accuracy and performance of current variational optical ow methods have considerably increased during the last years. The complexity of these techniques is high and enough care has to be taken for the implementation. The aim of this work is to present a comprehensible implementation of recent variational optical flow methods. We start with an energy model that relies on brightness and gradient constancy terms and a ow-based smoothness term. We minimize this energy model and derive an e cient implicit numerical scheme. In the experimental results, we evaluate the accuracy and performance of this implementation with the Middlebury benchmark database. We show that it is a competitive solution with respect to current methods in the literature. In order to increase the performance, we use a simple strategy to parallelize the execution on multi-core processors.

Model of vessels for the 3D reconstruction

[EN] In this paper, we present a vascular tree model made with synthetic materials and which allows us to obtain images to make a 3D reconstruction. In order to create this model, we have used PVC tubes of several diameters and lengths that will let us evaluate the accuracy of our 3D reconstruction. We have made the 3D reconstruction from a series of images that we have from our model and after we have calibrated the camera. In order to calibrate it we have used a corner detector. Also we have used Optical Flow techniques to follow the points through the images going and going back. Once we have the set of images where we have located a point, we have made the 3D reconstruction choosing by chance a couple of images and we have calculated the projection error. After several repetitions, we have found the best 3D location for the point.

A dynamic model of oceanic sulfur (DMOS) applied to the Sargasso Sea: Simulating the dimethylsulfide (DMS) summer paradox

[EN]A new one-dimensional model of DMSP/DMS dynamics (DMOS) is developed and applied to the Sargasso Sea in order to explain what drives the observed dimethylsulfide (DMS) summer paradox: a summer DMS concentration maximum concurrent with a minimum in the biomass of phytoplankton, the producers of the DMS precursor dimethylsulfoniopropionate (DMSP). Several mechanisms have been postulated to explain this mismatch: a succession in phytoplankton species composition towards higher relative abundances of DMSP producers in summer; inhibition of bacterial DMS consumption by ultraviolet radiation (UVR); and direct DMS production by phytoplankton due to UVR-induced oxidative stress. None of these hypothetical mechanisms, except for the first one, has been tested with a dynamic model. We have coupled a new sulfur cycle model that incorporates the latest knowledge on DMSP/DMS dynamics to a preexisting nitrogen/carbon-based ecological model that explicitly simulates the microbial-loop. This allows the role of bacteria in DMS production and consumption to be represented and quantified. The main improvements of DMOS with respect to previous DMSP/DMS models are the explicit inclusion of: solar-radiation inhibition of bacterial sulfur uptakes; DMS exudation by phytoplankton caused by solar-radiation-induced stress; and uptake of dissolved DMSP by phytoplankton. We have conducted a series of modeling experiments where some of the DMOS sulfur paths are turned “off” or “on,” and the results on chlorophyll-a, bacteria, DMS, and DMSP (particulate and dissolved) concentrations have been compared with climatological data of these same variables. The simulated rate of sulfur cycling processes are also compared with the scarce data available from previous works. All processes seem to play a role in driving DMS seasonality. Among them, however, solar-radiation-induced DMS exudation by phytoplankton stands out as the process without which the model is unable to produce realistic DMS simulations and reproduce the DMS summer paradox.

Liquid-liquid equilibria in binary solutions formed by [Pyridinium-Derived][F4B] ionic liquids and alkanols:new experimental data and validation of a multiparametric model for correlating LLE data

[EN]Experimental solubility data are presented for a set of binary systems composed of ionic liquids (IL) derived from pyridium, with the tetrafluoroborate anion, and normal alcohols ranging from ethanol to decanol, in the temperature interval of 275 420 K, at atmospheric pressure. For each case, the miscibility curve and the upper critical solubility temperature (UCST) values are presented. The effects of the ILs on the behavior of solutions with alkanols are analyzed, paying special attention to the pyridine derivatives, and considering a series of structural characteristics of the compounds involved.

Non-Markovian stochastic processes and their applications: from anomalous diffusion to time series analysis

This work provides a forward step in the study and comprehension of the relationships between stochastic processes and a certain class of integral-partial differential equation, which can be used in order to model anomalous diffusion and transport in statistical physics. In the first part, we brought the reader through the fundamental notions of probability and stochastic processes, stochastic integration and stochastic differential equations as well. In particular, within the study of H-sssi processes, we focused on fractional Brownian motion (fBm) and its discrete-time increment process, the fractional Gaussian noise (fGn), which provide examples of non-Markovian Gaussian processes. The fGn, together with stationary FARIMA processes, is widely used in the modeling and estimation of long-memory, or long-range dependence (LRD). Time series manifesting long-range dependence, are often observed in nature especially in physics, meteorology, climatology, but also in hydrology, geophysics, economy and many others. We deepely studied LRD, giving many real data examples, providing statistical analysis and introducing parametric methods of estimation. Then, we introduced the theory of fractional integrals and derivatives, which indeed turns out to be very appropriate for studying and modeling systems with long-memory properties. After having introduced the basics concepts, we provided many examples and applications. For instance, we investigated the relaxation equation with distributed order time-fractional derivatives, which describes models characterized by a strong memory component and can be used to model relaxation in complex systems, which deviates from the classical exponential Debye pattern. Then, we focused in the study of generalizations of the standard diffusion equation, by passing through the preliminary study of the fractional forward drift equation. Such generalizations have been obtained by using fractional integrals and derivatives of distributed orders. In order to find a connection between the anomalous diffusion described by these equations and the long-range dependence, we introduced and studied the generalized grey Brownian motion (ggBm), which is actually a parametric class of H-sssi processes, which have indeed marginal probability density function evolving in time according to a partial integro-differential equation of fractional type. The ggBm is of course Non-Markovian. All around the work, we have remarked many times that, starting from a master equation of a probability density function f(x,t), it is always possible to define an equivalence class of stochastic processes with the same marginal density function f(x,t). All these processes provide suitable stochastic models for the starting equation. Studying the ggBm, we just focused on a subclass made up of processes with stationary increments. The ggBm has been defined canonically in the so called grey noise space. However, we have been able to provide a characterization notwithstanding the underline probability space. We also pointed out that that the generalized grey Brownian motion is a direct generalization of a Gaussian process and in particular it generalizes Brownain motion and fractional Brownain motion as well. Finally, we introduced and analyzed a more general class of diffusion type equations related to certain non-Markovian stochastic processes. We started from the forward drift equation, which have been made non-local in time by the introduction of a suitable chosen memory kernel K(t). The resulting non-Markovian equation has been interpreted in a natural way as the evolution equation of the marginal density function of a random time process l(t). We then consider the subordinated process Y(t)=X(l(t)) where X(t) is a Markovian diffusion. The corresponding time-evolution of the marginal density function of Y(t) is governed by a non-Markovian Fokker-Planck equation which involves the same memory kernel K(t). We developed several applications and derived the exact solutions. Moreover, we considered different stochastic models for the given equations, providing path simulations.

Neuroprotective activity of guanosine in an in vitro model of Alzheimer's disease

The β-Amyloid (βA) peptide is the major component of senile plaques that are one of the hallmarks of Alzheimer’s Disease (AD). It is well recognized that Aβ exists in multiple assembly states, such as soluble oligomers or insoluble fibrils, which affect neuronal viability and may contribute to disease progression. In particular, common βA-neurotoxic mechanisms are Ca2+ dyshomeostasis, reactive oxygen species (ROS) formation, altered signaling, mitochondrial dysfunction and neuronal death such as necrosis and apoptosis. Recent study shows that the ubiquitin-proteasome pathway play a crucial role in the degradation of short-lived and regulatory proteins that are important in a variety of basic and pathological cellular processes including apoptosis. Guanosine (Guo) is a purine nucleoside present extracellularly in brain that shows a spectrum of biological activities, both under physiological and pathological conditions. Recently it has become recognized that both neurons and glia also release guanine-based purines. However, the role of Guo in AD is still not well established. In this study, we investigated the machanism basis of neuroprotective effects of GUO against Aβ peptide-induced toxicity in neuronal (SH-SY5Y), in terms of mitochondrial dysfunction and translocation of phosphatidylserine (PS), a marker of apoptosis, using MTT and Annexin-V assay, respectively. In particular, treatment of SH-SY5Y cells with GUO (12,5-75 μM) in presence of monomeric βA25-35 (neurotoxic core of Aβ), oligomeric and fibrillar βA1-42 peptides showed a strong dose-dependent inhibitory effects on βA-induced toxic events. The maximum inhibition of mitochondrial function loss and PS translocation was observed with 75 μM of Guo. Subsequently, to investigate whether neuroprotection of Guo can be ascribed to its ability to modulate proteasome activity levels, we used lactacystin, a specific inhibitor of proteasome. We found that the antiapoptotic effects of Guo were completely abolished by lactacystin. To rule out the possibility that this effects resulted from an increase in proteasome activity by Guo, the chymotrypsin-like activity was assessed employing the fluorogenic substrate Z-LLL-AMC. The treatment of SH-SY5Y with Guo (75 μM for 0-6 h) induced a strong increase, in a time-dependent manner, of proteasome activity. In parallel, no increase of ubiquitinated protein levels was observed at similar experimental conditions adopted. We then evaluated an involvement of anti and pro-apoptotic proteins such as Bcl-2, Bad and Bax by western blot analysis. Interestingly, Bax levels decreased after 2 h treatment of SH-SY5Y with Guo. Taken together, these results demonstrate that Guo neuroprotective effects against βA-induced apoptosis are mediated, at least partly, via proteasome activation. In particular, these findings suggest a novel neuroprotective pathway mediated by Guo, which involves a rapid degradation of pro-apoptotic proteins by the proteasome. In conclusion, the present data, raise the possibility that Guo could be used as an agent for the treatment of AD.

Sistemi liquido cristallini complessi: simulazioni al calcolatore e studi ESR

The aim of this PhD thesis was to study at a microscopic level different liquid crystal (LC) systems, in order to determine their physical properties, resorting to two distinct methodologies, one involving computer simulations, and the other spectroscopic techniques, in particular electron spin resonance (ESR) spectroscopy. By means of the computer simulation approach we tried to demonstrate this tool effectiveness for calculating anisotropic static properties of a LC material, as well as for predicting its behaviour and features. This required the development and adoption of suitable molecular models based on a convenient intermolecular potentials reflecting the essential molecular features of the investigated system. In particular, concerning the simulation approach, we have set up models for discotic liquid crystal dimers and we have studied, by means of Monte Carlo simulations, their phase behaviour and self­-assembling properties, with respect to the simple monomer case. Each discotic dimer is described by two oblate Gay­Berne ellipsoids connected by a flexible spacer, modelled by a harmonic "spring" of three different lengths. In particular we investigated the effects of dimerization on the transition temperatures, as well as on the characteristics of molecular aggregation displayed and the relative orientational order. Moving to the experimental results, among the many experimental techniques that are typically employed to evaluate LC system distinctive features, ESR has proved to be a powerful tool in microscopic scale investigation of the properties, structure, order and dynamics of these materials. We have taken advantage of the high sensitivity of the ESR spin probe technique to investigate increasingly complex LC systems ranging from devices constituted by a polymer matrix in which LC molecules are confined in shape of nano- droplets, as well as biaxial liquid crystalline elastomers, and dimers whose monomeric units or lateral groups are constituted by rod-like mesogens (11BCB). Reflection-mode holographic-polymer dispersed liquid crystals (H-PDLCs) are devices in which LCs are confined into nanosized (50­-300 nm) droplets, arranged in layers which alternate with polymer layers, forming a diffraction grating. We have determined the configuration of the LC local director and we have derived a model of the nanodroplet organization inside the layers. Resorting also to additional information on the nanodroplet size and shape distribution provided by SEM images of the H-PDLC cross-section, the observed director configuration has been modeled as a bidimensional distribution of elongated nanodroplets whose long axis is, on the average, parallel to the layers and whose internal director configuration is a uniaxial quasi- monodomain aligned along the nanodroplet long axis. The results suggest that the molecular organization is dictated mainly by the confinement, explaining, at least in part, the need for switching voltages significantly higher and the observed faster turn-off times in H-PDLCs compared to standard PDLC devices. Liquid crystal elastomers consist in cross-linked polymers, in which mesogens represent the monomers constituting the main chain or the laterally attached side groups. They bring together three important aspects: orientational order in amorphous soft materials, responsive molecular shape and quenched topological constraints. In biaxial nematic liquid crystalline elastomers (BLCEs), two orthogonal directions, rather than the one of normal uniaxial nematic, can be controlled, greatly enhancing their potential value for applications as novel actuators. Two versions of a side-chain BLCEs were characterized: side­-on and end­-on. Many tests have been carried out on both types of LCE, the main features detected being the lack of a significant dynamical behaviour, together with a strong permanent alignment along the principal director, and the confirmation of the transition temperatures already determined by DSC measurements. The end­-on sample demonstrates a less hindered rotation of the side group mesogenic units and a greater freedom of alignment to the magnetic field, as already shown by previous NMR studies. Biaxial nematic ESR static spectra were also obtained on the basis of Molecular Dynamics generated biaxial configurations, to be compared to the experimentally determined ones, as a mean to establish a possible relation between biaxiality and the spectral features. This provides a concrete example of the advantages of combining the computer simulation and spectroscopic approaches. Finally, the dimer α,ω-bis(4'-cyanobiphenyl-4-yl)undecane (11BCB), synthesized in the "quest" for the biaxial nematic phase has been analysed. Its importance lies in the dimer significance as building blocks in the development of new materials to be employed in innovative technological applications, such as faster switching displays, resorting to the easier aligning ability of the secondary director in biaxial phases. A preliminary series of tests were performed revealing the population of mesogenic molecules as divided into two groups: one of elongated straightened conformers sharing a common director, and one of bent molecules, which display no order, being equally distributed in the three dimensions. Employing this model, the calculated values show a consistent trend, confirming at the same time the transition temperatures indicated by the DSC measurements, together with rotational diffusion tensor values that follow closely those of the constituting monomer 5CB.

Non-equilibrium molecular dynamics study of an amphiphilic model system

Diese Doktorarbeit untersucht das Verhalten von komplexenFluidenunter Scherung, insbesondere den Einfluss von Scherflüssenauf dieStrukturbildung.Dazu wird ein Modell dieser entworfen, welches imRahmen von Molekulardynamiksimulationen verwendet wird.Zunächst werden Gleichgewichtseigenschaften dieses Modellsuntersucht.Hierbei wird unter anderem die Lage desOrdnungs--Unordnungsübergangs von derisotropen zur lamellaren Phase der Dimere bestimmt.Der Einfluss von Scherflüssen auf diese lamellare Phase wirdnununtersucht und mit analytischen Theorien verglichen. Die Scherung einer parallelen lamellaren Phase ruft eineNeuausrichtung des Direktors in Flussrichtung hervor.Das verursacht eine Verminderung der Schichtdicke mitsteigender Scherrateund führt oberhalb eines Schwellwertes zu Ondulationen.Ein vergleichbares Verhalten wird auch in lamellarenSystemengefunden, an denen in Richtung des Direktors gezogen wird.Allerdings wird festgestellt, dass die Art der Bifurkationenin beidenFällen unterschiedlich ist.Unter Scherung wird ein Übergang von Lamellen parallelerAusrichtung zu senkrechter gefunden.Dabei wird beoachtet, dass die Scherspannung in senkrechterOrientierungniedriger als in der parallelen ist.Dies führt unter bestimmten Bedingungen zum Auftreten vonScherbändern, was auch in Simulationen beobachtet wird. Es ist gelungen mit einem einfachen Modell viele Apsekte desVerhalten vonkomplexen Fluiden wiederzugeben. Die Strukturbildung hängt offensichtlich nurbedingt von lokalen Eigenschaften der Moleküle ab.

Informationsstrukturen der protokollbasierten Medizin

Die protokollbasierte Medizin stellt einen interdisziplinären Brennpunkt der Informatik dar. Als besonderer Ausschnitt der medizinischen Teilgebiete erlaubt sie die relativ formale Spezifikation von Prozessen in den drei Bereichen der Prävention, Diagnose und Therapie.Letzterer wurde immer besonders fokussiert und gilt seit jeher im Rahmen klinischer Studien als Projektionsfläche für informationstechnologische Konzepte. Die Euphorie der frühen Jahre ernüchtert sich jedoch bei jeder Bilanz. Nur sehr wenige der unzählbaren Projekte haben ihre Routine in der alltäglichen Praxis gefunden. Die meisten Vorhaben sind an der Illusion der vollständigen Berechenbarkeit medizinischer Arbeitsabläufe gescheitert. Die traditionelle Sichtweise der klinischen Praxis beruht auf einer blockorientierten Vorstellung des Therapieausführungsprozesses. Sie entsteht durch seine Zerlegung in einzelne Therapiezweige, welche aus vordefinierten Blöcken zusammengesetzt sind. Diese können sequentiell oder parallel ausgeführt werden und sind selbst zusammengesetzt aus jeweils einer Menge von Elementen,welche die Aktivitäten der untersten Ebene darstellen. Das blockorientierte Aufbaumodell wird ergänzt durch ein regelorientiertes Ablaufmodell. Ein komplexes Regelwerk bestimmt Bedingungen für die zeitlichen und logischen Abhängigkeiten der Blöcke, deren Anordnung durch den Ausführungsprozeß gebildet wird. Die Modellierung der Therapieausführung steht zunächst vor der grundsätzlichen Frage, inwieweit die traditionelle Sichtweise für eine interne Repräsentation geeignet ist. Das übergeordnete Ziel besteht in der Integration der unterschiedlichen Ebenen der Therapiespezifikation. Dazu gehört nicht nur die strukturelle Komponente, sondern vorallem die Ablaufkomponente. Ein geeignetes Regelmodell ist erforderlich, welches den spezifischen Bedürfnissen der Therapieüberwachung gerecht wird. Die zentrale Aufgabe besteht darin, diese unterschiedlichen Ebenen zusammenzuführen. Eine sinnvolle Alternative zur traditionellen Sichtweise liefert das zustandsorientierte Modell des Therapieausführungsprozesses. Das zustandsorientierte Modell beruht auf der Sichtweise, daß der gesamte Therapieausführungsprozeß letztendlich eine lineare Folge von Zuständen beschreibt, wobei jeder Zustandsübergang durch ein Ereignis eingeleitet wird, an bestimmte Bedingungen geknüpft ist und bestimmte Aktionen auslösen kann. Die Parallelität des blockorientierten Modells tritt in den Hintergrund, denn die Menge der durchzuführenden Maßnahmen sind lediglich Eigenschaften der Zustände und keine strukturellen Elemente der Ablaufspezifikation. Zu jedem Zeitpunkt ist genau ein Zustand aktiv, und er repräsentiert eine von endlich vielen klinischen Situationen, mit all ihren spezifischen Aktivitäten und Ausführungsregeln. Die Vorteile des zustandsorientierten Modells liegen in der Integration. Die Grundstruktur verbindet die statische Darstellung der möglichen Phasenanordnungen mit der dynamischen Ausführung aktiver Regeln. Die ursprünglichen Inhalte des blockorientierten Modells werden als gewöhnliche Eigenschaften der Zustände reproduziert und stellen damit nur einen Spezialfall der zustandsbezogenen Sicht dar.Weitere Möglichkeiten für die Anreicherung der Zustände mit zusätzlichen Details sind denkbar wie sinnvoll. Die Grundstruktur bleibt bei jeder Erweiterung jedoch die gleiche. Es ergibt sich ein wiederverwendbares Grundgerüst,ein gemeinsamer Nenner für die Erfüllung der Überwachungsaufgabe.

Physical model of PD behavior and relevant damage growth from micro-cavities in polyethylene-based material under AC voltage

In the framework of developing defect-based life models, in which breakdown is explicitly associated with partial discharge (PD)-induced damage growth from a defect, ageing tests and PD measurements were carried out in the lab on polyethylene (PE) layered specimens containing artificial cavities. PD activity was monitored continuously during aging. A quasi-deterministic series of stages can be observed in the behavior of the main PD parameters (i.e. discharge repetition rate and amplitude). Phase-resolved PD patterns at various ageing stages were reproduced by numerical simulation which is based on a physical discharge model devoid of adaptive parameters. The evolution of the simulation parameters provides insight into the physical-chemical changes taking place at the dielectric/cavity interface during the aging process. PD activity shows similar time behavior under constant cavity gas volume and constant cavity gas pressure conditions, suggesting that the variation of PD parameters may not be attributed to the variation of the gas pressure. Brownish PD byproducts, consisting of oxygen containing moieties, and degradation pits were found at the dielectric/cavity interface. It is speculated that the change of PD activity is related to the composition of the cavity gas, as well as to the properties of dielectric/cavity interface.

Populationsdynamik des Cydia pomonella Granulovirus

Das Cydia pomonella Granulovirus (CpGV, Fam. Baculoviridae) ist ein sehr virulentes und hoch spezifisches Pathogen des Apfelwicklers (Cydia pomonella), das seit mehreren Jahren in der Bundesrepublik Deutschland und anderen Ländern der EU als Insektizid zugelassen ist. Wie andere Baculoviren auch befällt es die Larven der Insekten und ist aufgrund seiner Selektivität für Nicht-Zielorganismen unbedenklich. In der Vergangenheit konzentrierte sich die Erforschung des CpGV auf Bereiche, die für die Anwendung im Pflanzenschutz relevant waren, wobei nach fast 20 Jahren nach der ersten Zulassung noch immer nicht bekannt ist, ob und wie sich das CpGV in der Umwelt etablieren kann. Im Rahmen der vorliegenden Arbeit wurden verschiedene Parameter, mit deren Hilfe die Populationsdynamik des CpGV beschrieben werden kann, analysiert und quantitativ bestimmt. Neben den biologischen Eigenschaften wie Virulenz, DNA-Charakterisierung und Quantifizierung der Virusnachkommenschaft wurden insbesondere die horizontale sowie die vertikale Transmission, die Inaktivierung und die Infektion später Larvenstadien untersucht. Letztlich wurden die ermittelten Parameter zusammen mit Daten aus der Literatur in ein mathematisches Modell integriert. Um die Wahrscheinlichkeit der horizontalen Transmission zu quantifizieren, wurde ein Modellsystem mit losen Äpfeln etabliert, in dem verschiedene Szenarien möglicher horizontaler Transmission unter definierten Laborbedingungen getestet wurden. In Versuchsserien, in denen ein Virusfleck, entsprechend der produzierten Virusmenge einer Eilarve, auf einen Apfel appliziert worden war, war unter den aufgesetzten Apfelwicklerlarven lediglich eine sehr geringe Mortalität von 3 - 6% zu beobachten. Wurde jedoch ein an einer Virusinfektion gestorbener Larvenkadaver als Inokulum verwendet, lag die Mortalitätsrate aufgesetzter Larven bei über 40%. Diese beobachtete hohe horizontale Transmissionsrate konnte mit dem Verhalten der Larven erklärt werden. Die Larven zeigten eine deutliche Einbohrpräferenz für den Stielansatz bzw. den Kelch, wodurch die Wahrscheinlichkeit des Zusammentreffens einer an der Infektion verendeten Larve mit einer gesunden Larve um ein Vielfaches zunahm. In einem ähnlich angelegten Freilandversuch konnte eine horizontale Transmission nicht belegt werden. Der Unterschied zur Kontrollgruppe fiel aufgrund einer hohen natürlichen Mortalität und einer damit einhergehenden niedrigen Dichte der Larven zu gering aus. Parallel hierzu wurde außerdem eine Halbwertszeit von 52 Sonnenstunden für das CpGV ermittelt. Weiterhin konnte festgestellt werden, dass die Mortalität von späteren Larvenstadien, die 14 Tage Zeit hatten sich in die Äpfel einzubohren, bevor eine CpGV-Applikation durchgeführt wurde, ebenso hoch war wie bei Larven, die sich im L1-Stadium auf der Apfeloberfläche infizierten. Aufgrund des höheren Alters jener Larven war der Fraßschaden an befallenen Äpfeln jedoch wesentlich größer und vergleichbar mit dem Fraßschaden einer unbehandelten Kontrolle. Der Versuch zur vertikalen Transmission zeigte dass, obwohl die verwendete Apfelwicklerzucht nicht frei von CpGV war, die Mortalitätsrate der Nachkommen subletal infizierter Weibchen (44%) jedoch deutlich höher war als die der Nachkommen subletal infizierter Männchen (28%) und der unbehandelten Kontrolle (27%). Auch in den PCR-Analysen konnte eine größere Menge an CpGV-Trägern bei den Nachkommen subletal infizierter Weibchen (67%) als bei den Nachkommen subletal infizierter Männchen (49%) und bei der Kontrolle (42%) nachgewiesen werden. Die Ergebnisse deuten darauf hin, dass eine Infektion durch subletal infizierte Weibchen vertikal in die nächste Generation übertragen werden kann. Dies lässt erkennen, dass in der Folgegeneration des Apfelwicklers eine zusätzliche Wirkung des CpGV durch vertikale Transmission auftreten kann. Hierin wäre auch ein potentieller Mechanismus für eine dauerhafte Etablierung des Virus zu sehen. Letztlich wurden alle Parameter, die die CpGV-Apfelwickler-Beziehung beschreiben, in ein mathematisches Modell GRANULO integriert. Nach einer Sensitivitätsanalyse wurde GRANULO teilweise mit Daten aus den Freilandversuchen verifiziert. Durch Modifikation der Virusparameter im Modell konnte anschließend der Einfluss veränderter biologischer Eigenschaften (UV-Stabilität und Transmissionsraten) der Viren in Simulationen theoretisch erprobt werden. Das beschriebene Modell, das allerdings noch einer weitergehenden Verifizierung und Validierung bedarf, ist eine erste Annäherung an die quantitative Erfassung und Modellierung der Populationsdynamik des Systems CpGV-Apfelwickler. Die im Zusammenhang mit der Populationsdynamik des Apfelwicklers erhobenen Daten können einen wertvollen Beitrag zur Optimierung von Kontrollstrategien des Apfelwicklers mittels CpGV leisten. Außerdem geben sie Aufschluss über die Etablierungsmöglichkeiten dieses Bioinsektizids.

Simulations of physics and chemistry of polar stratospheric clouds with a general circulation model

A polar stratospheric cloud submodel has been developed and incorporated in a general circulation model including atmospheric chemistry (ECHAM5/MESSy). The formation and sedimentation of polar stratospheric cloud (PSC) particles can thus be simulated as well as heterogeneous chemical reactions that take place on the PSC particles. For solid PSC particle sedimentation, the need for a tailor-made algorithm has been elucidated. A sedimentation scheme based on first order approximations of vertical mixing ratio profiles has been developed. It produces relatively little numerical diffusion and can deal well with divergent or convergent sedimentation velocity fields. For the determination of solid PSC particle sizes, an efficient algorithm has been adapted. It assumes a monodisperse radii distribution and thermodynamic equilibrium between the gas phase and the solid particle phase. This scheme, though relatively simple, is shown to produce particle number densities and radii within the observed range. The combined effects of the representations of sedimentation and solid PSC particles on vertical H2O and HNO3 redistribution are investigated in a series of tests. The formation of solid PSC particles, especially of those consisting of nitric acid trihydrate, has been discussed extensively in recent years. Three particle formation schemes in accordance with the most widely used approaches have been identified and implemented. For the evaluation of PSC occurrence a new data set with unprecedented spatial and temporal coverage was available. A quantitative method for the comparison of simulation results and observations is developed and applied. It reveals that the relative PSC sighting frequency can be reproduced well with the PSC submodel whereas the detailed modelling of PSC events is beyond the scope of coarse global scale models. In addition to the development and evaluation of new PSC submodel components, parts of existing simulation programs have been improved, e.g. a method for the assimilation of meteorological analysis data in the general circulation model, the liquid PSC particle composition scheme, and the calculation of heterogeneous reaction rate coefficients. The interplay of these model components is demonstrated in a simulation of stratospheric chemistry with the coupled general circulation model. Tests against recent satellite data show that the model successfully reproduces the Antarctic ozone hole.

A structural and metamorphic study of the southern Menderes Massif (Western Turkey)

P-T conditions, paragenetic studies and the relation between mineral growth, deformation and - when possible- isograd minerals have been used to describe the type of metamorphism involved within lower units of the southern Menderes Massif of the Anatolide Belt in western Turkey. The study areas mainly consist of Proterozoic orthogneiss and surrounding schists of presumed Paleozoic age. Both units are seen as nappes in the southern study area, the Çine and the Selimiye nappe, on the whole corresponding to Proterozoic orthogneiss and surrounding schists, respectively. The Çine and Selimiye nappes are part of a complex geological structure within the core series of the Menderes Massif. Their emplacement under lower greenschist facies conditions, would result from closure of the northern Neo-Thethys branch during the Eocene. These two nappes are separated by a major tectonic structure, the Selimiye shear zone, which records top-to-the-S shearing under greenschist facies conditions. Amphibolite to upper amphibolite facies metamorphism is widely developed within the metasedimentary rocks of the Çine nappe whereas no metamorphism exceeding lower amphibolite facies has been observed in the Selimiye nappe. In the southern margin of the Çine Massif, around Selimiye and Millas villages, detailed sampling has been undertaken in order to map mineral isograds within the Selimiye nappe and to specify P-T conditions in this area. The data collected in this area reveals a global prograde normal erosion field gradient from south to north and toward the orthogneiss. The mineralogical parageneses and P-T estimates are correlated with Barrovian-type metamorphism. A jump of P-T conditions across the Selimiye shear zone has been identified and estimated c. 2 kbar and 100 °C which evidences the presence of amphibolite facies metasedimentary rocks near the orthogneiss. Metasedimentary rocks from the overlying Selimiye nappe have maximum P-T conditions of c. 4-5 kbar and c. 525 °C near the base of the nappe. Metasedimentary rocks from the Çine nappe underneath the Selimiye shear zone record maximum P-T conditions of about 7 kbar and >550 °C. Kinematic indicators in both nappes consistently show a top-S shear sense. Metamorphic grade in the Selimiye nappe decreases structurally upwards as indicated by mineral isograds defining the garnet-chlorite zone at the base, the chloritoid-biotite zone and the biotite-chlorite zone at the top of the nappe. The mineral isograds in the Selimiye nappe run parallel to the regional SR foliation. 40Ar/39Ar mica ages indicate an Eocene age of metamorphism in the Selimiye nappe and underneath the Çine nappe in this area. Metasedimentary rocks of the Çine nappe 20-30 km north of the Selimiye shear zone record maximum P-T conditions of 8-11 kbar and 600-650 °C. Kinematic indicators show mainly top-N shear sense associated with prograde amphibolite facies metamorphism. An age of about 550 Ma could be indicated for amphibolite facies metamorphism and associated top-N shear in the orthogneiss and metasedimentary rocks of the Çine nappe. However, there is no evidence for polymetamorphism in the 6 metasedimentary rocks of the Çine nappe, making tectonic interpretations about late Neoproterozoic to Cambrian and Tertiary metamorphic events speculative. In the western margin of the Çine Massif metamorphic mineral parageneses and pressure– temperature conditions lead to similar conclusion regarding the erosion field gradient, prograde normal toward the orthogneiss. The contact between orthogneiss and surrounding metasedimentary rocks is mylonitic and syn-metamorphism. P-T estimates are those already observed within the Selimiye nappe and correlated with lower amphibolite facies parageneses. Finally additional data in the eastern part and a general paragenetic study within the Menderes Massif lower units, the Çine and the Selimiye nappes, strongly suggest a single Barrovian-type metamorphism predating Eocene emplacement of the high pressure–low temperature Lycean and Cycladic blueschist nappes. Metamorphic mineral parageneses and pressure–temperature conditions do not support the recently proposed model of high pressure–low temperature metamorphic overprinting, which implies burial of the lower units of the Menderes Massif up to depth of 30 km, as a result of closure of the Neo-Tethys. According to the geochronological problem outlined during this thesis, there are two possible schemes: either Barrovian-type metamorphism is Proterozoic in age and part of the sediments from Selimiye nappe (lower amphibolite facies) has to be proterozoic of age too, or Barrovian-type metamorphism in Eocene of age. In the first case the structure observed now in the core series would correspond to simple exhumation of Proterozoic basement. In the latter case a possible correlation with closure of Neo-Tethys (sensu stricto, southern branch) is envisaged.

Structural and strain analysis in the Late Paleozoic coastal accretionary wedge of central Chile

Abstract In this study structural and finite strain data are used to explore the tectonic evolution and the exhumation history of the Chilean accretionary wedge. The Chilean accretionary wedge is part of a Late Paleozoic subduction complex that developed during subduction of the Pacific plate underneath South America. The wedge is commonly subdivided into a structurally lower Western Series and an upper Eastern Series. This study shows the progressive development of structures and finite strain from the least deformed rocks in the eastern part of the Eastern Series of the accretionary wedge to higher grade schist of the Western Series at the Pacific coast. Furthermore, this study reports finite-strain data to quantify the contribution of vertical ductile shortening to exhumation. Vertical ductile shortening is, together with erosion and normal faulting, a process that can aid the exhumation of high-pressure rocks. In the east, structures are characterized by upright chevron folds of sedimentary layering which are associated with a penetrative axial-plane foliation, S1. As the F1 folds became slightly overturned to the west, S1 was folded about recumbent open F2 folds and an S2 axial-plane foliation developed. Near the contact between the Western and Eastern Series S2 represents a prominent subhorizontal transposition foliation. Towards the structural deepest units in the west the transposition foliation became progressively flat lying. Finite-strain data as obtained by Rf/Phi and PDS analysis in metagreywacke and X-ray texture goniometry in phyllosilicate-rich rocks show a smooth and gradual increase in strain magnitude from east to west. There are no evidences for normal faulting or significant structural breaks across the contact of Eastern and Western Series. The progressive structural and strain evolution between both series can be interpreted to reflect a continuous change in the mode of accretion in the subduction wedge. Before ~320-290 Ma the rocks of the Eastern Series were frontally accreted to the Andean margin. Frontal accretion caused horizontal shortening and upright folds and axial-plane foliations developed. At ~320-290 Ma the mode of accretion changed and the rocks of the Western Series were underplated below the Andean margin. This basal accretion caused a major change in the flow field within the wedge and gave rise to vertical shortening and the development of the penetrative subhorizontal transposition foliation. To estimate the amount that vertical ductile shortening contributed to the exhumation of both units finite strain is measured. The tensor average of absolute finite strain yield Sx=1.24, Sy=0.82 and Sz=0.57 implying an average vertical shortening of ca. 43%, which was compensated by volume loss. The finite strain data of the PDS measurements allow to calculate an average volume loss of 41%. A mass balance approximates that most of the solved material stays in the wedge and is precipitated in quartz veins. The average of relative finite strain is Sx=1.65, Sy=0.89 and Sz=0.59 indicating greater vertical shortening in the structurally deeper units. A simple model which integrates velocity gradients along a vertical flow path with a steady-state wedge is used to estimate the contribution of deformation to ductile thinning of the overburden during exhumation. The results show that vertical ductile shortening contributed 15-20% to exhumation. As no large-scale normal faults have been mapped the remaining 80-85% of exhumation must be due to erosion.