Räumliche Analyse und Gefährdungsmodellierung von Rutschungen in der rhenodanubischen Flyschzone (NÖ)

Diese Arbeit zeigt die wichtigsten rutschungsfördernden Faktoren der rhenodanubischen Flyschzone von Niederösterreich auf und stellt die gefährdeten Bereiche anhand von Gefahrenhinweiskarten räumlich differenziert dar. Durch Verwendung von zwei Modellierungsansätzen (logistische Regression und Landslide Susceptibility Index) und zwei unabhängig voneinander erstellten Rutschungsinventaren wird sowohl der Einfluss der Methode als auch der zugrundeliegenden Inventare dargestellt. Trotz der hohen statistischen Gütemaße belegen die Ergebnisse Limitationen einer rein quantitativen Herangehensweise sowie eine hohe Abhängigkeit von der zugrundeliegenden Datenbasis. Eine generierte Gefahrenhinweiskarte weist sowohl eine hohe Vorhersagerate als auch eine hohe qualitative geomorphologische Güte auf

Lost in folding space? Comparing four variants of the thermodynamic model for RNA secondary structure prediction

Janssen S, Schudoma C, Steger G, Giegerich R. Lost in folding space? Comparing four variants of the thermodynamic model for RNA secondary structure prediction. BMC Bioinformatics. 2011;12(1): 429.BACKGROUND:Many bioinformatics tools for RNA secondary structure analysis are based on a thermodynamic model of RNA folding. They predict a single, "optimal" structure by free energy minimization, they enumerate near-optimal structures, they compute base pair probabilities and dot plots, representative structures of different abstract shapes, or Boltzmann probabilities of structures and shapes. Although all programs refer to the same physical model, they implement it with considerable variation for different tasks, and little is known about the effects of heuristic assumptions and model simplifications used by the programs on the outcome of the analysis.RESULTS:We extract four different models of the thermodynamic folding space which underlie the programs RNAfold, RNAshapes, and RNAsubopt. Their differences lie within the details of the energy model and the granularity of the folding space. We implement probabilistic shape analysis for all models, and introduce the shape probability shift as a robust measure of model similarity. Using four data sets derived from experimentally solved structures, we provide a quantitative evaluation of the model differences.CONCLUSIONS:We find that search space granularity affects the computed shape probabilities less than the over- or underapproximation of free energy by a simplified energy model. Still, the approximations perform similar enough to implementations of the full model to justify their continued use in settings where computational constraints call for simpler algorithms. On the side, we observe that the rarely used level 2 shapes, which predict the complete arrangement of helices, multiloops, internal loops and bulges, include the "true" shape in a rather small number of predicted high probability shapes. This calls for an investigation of new strategies to extract high probability members from the (very large) level 2 shape space of an RNA sequence. We provide implementations of all four models, written in a declarative style that makes them easy to be modified. Based on our study, future work on thermodynamic RNA folding may make a choice of model based on our empirical data. It can take our implementations as a starting point for further program development

Quantum capacitance mediated carbon nanotube optomechanics

Cavity optomechanics allows the characterization of a vibration mode, its cooling and quantum manipulation using electromagnetic fields. Regarding nanomechanical as well as electronic properties, single wall carbon nanotubes are a prototypical experimental system. At cryogenic temperatures, as high quality factor vibrational resonators, they display strong interaction between motion and single-electron tunneling. Here, we demonstrate large optomechanical coupling of a suspended carbon nanotube quantum dot and a microwave cavity, amplified by several orders of magnitude via the nonlinearity of Coulomb blockade. From an optomechanically induced transparency (OMIT) experiment, we obtain a single photon coupling of up to g(0) = 2 . 95 Hz. This indicates that normal mode splitting and full optomechanical control of the carbon nanotube vibration in the quantum limit is reachable in the near future. Mechanical manipulation and characterization via the microwave field can be complemented by the manifold physics of quantum-confined single electron devices

Application of beta regression for the prediction of landslide areal density in South Tyrol, Italy

The concept of landslide hazard entails evaluating landslide occurrence in space (i.e., where landslides may occur), in time (i.e., when or how often landslides may occur), and their intensity (i.e., how destructive landslides may be). At regional scales, data-driven methods are implemented to separately analyze the spatial component (i.e., landslide susceptibility) and the temporal conditions leading to landslide occurrence, such as rainfall thresholds. However, assessing how large a landslide may develop once triggered is seldom conducted and poses a persistent challenge to satisfying the complete definition of landslide hazard.So far, only a few publications have addressed this issue by predicting the total areal extent of landslides based on certain mapping units, such as slope units. Limitations arise since the total areal extent of landslides within a mapping unit is strongly influenced by the size of the mapping unit, leading to larger mapping units being more likely to encompass larger total landslide areas. To tackle these challenges, this study aims to predict the landslide area proportion per slope unit in South Tyrol, Italy (7,400 km²). Our approach built upon past landslide occurrences from 2000 to 2020, systematically related to damage-causing and infrastructure-threatening landslide events. The method involved delineating slope units, filtering the landslide inventory, designing the sampling strategy, removing trivial areas, and aggregating the environmental variables (e.g., topography, lithology, land cover, and precipitation) to the slope unit partition. We tested a generalized additive beta regression model to estimate statistical relationships between the various static predictors and the target landslide areal density. The resulting spatially explicit predictions are evaluated through cross-validation from multiple perspectives. Applications and shortcomings of the approach are discussed.The proposed method is anticipated to provide valuable insights and alternatives to assessing landslide intensity and moving toward landslide hazard in a data-driven context. The outcomes associated with this research are framed within the PROSLIDE project, which has received funding from the research program Research Südtirol/Alto Adige 2019 of the Autonomous Province of Bozen/Bolzano – Südtirol/Alto Adige

Wipptal South Pilot Action Region: Gravity-Driven Natural Hazards and Forest Types

This chapter describes the Wipptal South Pilot Action Region (PAR) in South Tyrol, where forests are well recognized to play a crucial role in protecting against a variety of gravity-driven natural hazards, such as landslides, debris flows, rock falls and snow avalanches. The chapter presents the three municipalities in the PAR area in terms of socio-environmental context, gravity-driven natural hazards and forest characteristics. The presented best-practice example describes the results of a former project entitled “Waldtypisierung Südtirol” (Eng. Forest Characterization South Tyrol) that focused on a detailed description of forests in South Tyrol and the development of a handbook for foresters. It is shown that the Wipptal South PAR as being is frequently affected by a variety of gravity-induced hazards while highlighting the critical role of forest in protecting people and their properties. Appropriate forest management strategies are vital to maintain and increase tree species diversity (e.g. populating fir) and the associated protective forest function. In this context, climate change effects, such as an increasing threat of bark beetle infestation due to rising drought stress or the consequences of associated extreme weather events (e.g. storms), pose major challenges for the local forests and their protective function