11 research outputs found
The only known cyclopygidââathelopticâ trilobite fauna from North America: the upper Ordovician fauna of the Pyle Mountain Argillite and its palaeoenvironmental significance
The trilobite fauna of the upper Ordovician (middle Katian) Pyle Mountain Argillite comprises a mixture of abundant mesopelagic cyclopygids and other pelagic taxa and a benthic fauna dominated by trilobites lacking eyes. Such faunas were widespread in deep water environments around Gondwana and terranes derived from that continent throughout Ordovician time but this is the only known record of such a fauna from North America and thus from Laurentia. It probably reflects a major sea level rise (the âLinearis drowning eventsâ) as does the development of coeval cyclopygid-dominated deep water trilobite faunas in terranes that were marginal to Laurentia and are now preserved in Ireland and Scotland. The Pyle Mountain Argillite trilobite fauna occurs with a deep water Foliomena brachiopod fauna and comprises 22 species. Pelagic trilobites (mostly cyclopygids) constitute 36% of the preserved sclerites, and 45% of the fauna is the remains of trilobites lacking eyes, including one new species, Dindymene whittingtoni sp. nov. Three species of cyclopygid are present, belonging in Cyclopyge, Symphysops and Microparia (Heterocyclopyge). Cyclopygids are widely thought to have been stratified in the water column in life and thus their taxonomic diversity reflects the relative depths of the sea-beds on which their remains accumulated. A tabulation of middle and upper Katian cyclopygid-bearing faunas from several palaeoplates and terranes arranged on the basis of increasing numbers of cyclopygid genera allows an assessment of the relative depth ranges of the associated benthic taxa. The Pyle Mountain Argillite fauna lies towards the deeper end of this depth spectrum
Cooling potential of green spaces in the Vienna metropolitan area during extended periods of drought
Parquet DÎA with self-consistent recalculation of the impurity vertex
Im Rahmen dieser Arbeit wurde die erste völlig selbstkonsistente Implementierung der Dynamischen Vertex Approximation (DGA) durchgefĂŒhrt. Diese Methode erlaubt die Behandlung nicht-lokaler Korrelationen in stark korrelierten Elektronensystemen, die zu einigen der interessantesten PhĂ€nomenen der Festkörperphysik fĂŒhren. Wir stellen die zugrundeliegenden Gleichungen, die Parquet Gleichungen, vor und skizzieren den Aufbau des Programms victory-code, das zur Lösung der Parquet Gleichungen verwendet wurde. Wir zeigen, wie man den völlig irreduziblen Vertex, der eine wichtige Komponente der DGA bildet, von den Zweiteilchen Greenschen Funktionen erhĂ€lt, die wiederum mittels CT-QMC von einem Störstellenmodell berechnet werden. Ein besonderer Fokus dieser Arbeit liegt auf der Neuberechnung des Störstellenmodells, sodass Selbstkonsistenz auf dem Niveau der lokalen Einteilchen Greenschen Funktion erreicht wird. Diese (Ă€uĂere) Selbstkonsistenz hat sich als besonders wichtig bei nicht-lokalen Wechselwirkungen herausgestellt, wie sie fĂŒr das Benzol-MolekĂŒl eingefĂŒhrt wurden. Wir prĂ€sentieren auĂerdem Ergebnisse fĂŒr das zweidimensionale Hubbard Modell auf einem quadratischen Gitter, wo die Ă€uĂere Selbstkonsistenz das Ergebnis fĂŒr die derzeit ereichbaren Parameter nicht stark beeinflusst. Dennoch deuten die Ergebnisse auf mögliche d-Wellen Supraleitung im zweidimensionalen Hubbard Modell hin.In this thesis, the first fully self-consistent implementation of the dynamical vertex approximation (DGA) in its parquet formulation was realized. The method provides a framework to treat non-local correlations in strongly correlated electron systems, which lead to some of the most interesting phenomena in solid-state physics. In this thesis, we give an introduction to the parquet-, Bethe-Salpeter- and Schwinger-Dyson-equations, which form the backbone of DGA. We further give a sketch of the parquet-solver used within this work, the victory-code. We then show how to extract the fully irreducible vertex, a key component of DGA, from two-particle Green's functions obtained in a CTQMC solution of the local impurity problem. A special focus lies on the update of the impurity problem to achieve self-consistency at the level of the local one-particle Green's function. This (outer) self-consistency is found to be particularly important with the introduction of non-local interactions, as is shown for the case of the benzene molecule. We also present results for the two dimensional Hubbard model on the square lattice, where the outer self-consistency does not impact the solution in a significant way at the currently attainable parameters. Nevertheless, the results indicate possible d-wave superconducting pairing in the two-dimensional Hubbard model.5
Fehl am Ort â die deplatzierte Frau
Diese Arbeit widmet sich der Evokation von Raum in Grillparzers Dramenwerken Sappho, Das goldene VlieĂ und Libussa mit dem Ziel, nachweislich zu belegen, dass durch den konstruierten Raum Einfluss auf die IdentitĂ€ten der (weiblichen) Figuren geĂŒbt wird und das Scheitern der Frauen als Resultat gesellschaftlicher Hierarchien gewertet werden kann, die durch rĂ€umliche Strukturen produziert und legitimiert werden.
Der Raum wird dabei nicht als einfache Gegebenheit begriffen, sondern als dynamisches, verĂ€nderliches Produkt und gleichzeitig zu einer Bedingung und zu einem Ergebnis sozialer Strukturen gemacht. In Anbetracht der Annahme, dass sich der soziale Raum durch Handlungen und Beziehungen manifestiert, liegt der Fokus der Arbeit auf der Positionierung und der Bewegung der Figuren im Raum. Aufgrund der Tatsache, dass der Raum kulturell produziert und kulturell produktiv ist, können durch eine sorgfĂ€ltige Analyse SchlĂŒsse ĂŒber dargestellte gesellschaftliche GefĂŒge gezogen werden und Aussagen ĂŒber die vorherrschenden sozialen Klassen im Raum getroffen werden. Ein weiterer Schwerpunkt dieser Arbeit liegt auf der geschlechtskritischen ĂberprĂŒfung der evozierten RĂ€ume, denn der enge Bezug zwischen Raumerfahrung und IdentitĂ€tskonstitution kann hinsichtlich der Konstruktion von Weiblichkeit aufschlussreich sein.
Die Diplomarbeit soll einen Beitrag dazu leisten, die BeschĂ€ftigung mit dem Raum als KulturtrĂ€ger in der Literatur voranzutreiben und dabei an die raumtheoretischen Konzepte der Sozial- und Kulturwissenschaften anknĂŒpfen
Hydromorphological Assessment as the Basis for Ecosystem Restoration in the Nanxi River Basin (China)
Hydromorphology is a major component of riverine ecosystems. Therefore, proper assessments of the status quo, as well as the detection of pressures in river basins, are of high relevance. Process-based morphological methods have been developed, relying on a broad data basis and resulting in suitable instruments, such as the Morphological Quality Index (MQI). In this study, the hydromorphological status of the Nanxi river system in Eastern China was assessed by an adapted application of the MQI. Adaptations and amendments in the methodical approach were developed in cycles and carried out to transfer the well-approved method for European river systems to another geographical setting. The strengths of the tested approach are the few data requirements, the applicability for modified river basins, and the decoupling of historical information. The assessment of 161 river kilometers resulted in a hydromorphological status quo with the focus being a relative comparison of different sections ranging from âmoderateâ to âbadâ, with an average classification of a âpoorâ state. On the one hand, the results build the basis for future restoration and river management planning, specifically, and on the other hand, they create a foundation for the development of an assessment method fitted for modified river systems conditions
Hydromorphological Assessment as the Basis for Ecosystem Restoration in the Nanxi River Basin (China)
Hydromorphology is a major component of riverine ecosystems. Therefore, proper assessments of the status quo, as well as the detection of pressures in river basins, are of high relevance. Process-based morphological methods have been developed, relying on a broad data basis and resulting in suitable instruments, such as the Morphological Quality Index (MQI). In this study, the hydromorphological status of the Nanxi river system in Eastern China was assessed by an adapted application of the MQI. Adaptations and amendments in the methodical approach were developed in cycles and carried out to transfer the well-approved method for European river systems to another geographical setting. The strengths of the tested approach are the few data requirements, the applicability for modified river basins, and the decoupling of historical information. The assessment of 161 river kilometers resulted in a hydromorphological status quo with the focus being a relative comparison of different sections ranging from “moderate” to “bad”, with an average classification of a “poor” state. On the one hand, the results build the basis for future restoration and river management planning, specifically, and on the other hand, they create a foundation for the development of an assessment method fitted for modified river systems conditions