The Trouble with Glaciers: A Case Study in the Region of San Juan, Argentina

In 2010 Argentina passed the first glacier law in the world. This law regulates the protection of glaciers and the periglacial environment against external influences. Within the framework of this law, the Argentine glacier inventory was developed. This inventory includes glaciers, snow patches and rock glaciers. The National Institute of Snow, Ice and Environmental Research (IANIGLA), headed by Ricardo Villalba, was responsible for compiling the Argentinean glacier inventory. Between 2015 and 2017 there were three accidents with cyanide at the Veladero Mine in the Province of San Juan. In one case the cyanide reached the watershed. Following these accidents, the environmental group Jáchal No Se Toca filed lawsuits against both the mine operators (Barrick Gold) and IANIGLA. Ricardo Villalba and IANIGLA were accused of not implementing the law correctly because they used the standard threshold for glaciers of one hectare. The Critical Physical Geography Approach is used to illuminate and analyze the conflict between the different parties. This approach is used because the approach assumes that physical landscape changes do not take place in a social vacuum, but are influenced by social aspects. To analyze the social aspects of the conflict, a content analysis of the definitions, values and boundaries of a glacier is made. This analysis is carried out with different stakeholders involved. Furthermore, it is analyzed how the different stakeholders understand and interpret the term "glacier". In order to understand the physical aspects of this conflict, two inventories of satellite images from ASTER and Sentinel-2 have been created for comparison it with the Argentine glacier inventory. The organization Center for Human Right and Environment (CEDHA) is very critical of the Argentine glacier inventory, so the inventory of this organization is also used for further analysis. To fully understand the conflict, it is important to understand the amount of water stored in these different features, as the Veladero Mine is located in an arid area. The results show that Ricardo Villalba and the institution IANIGLA did not make any obvious mistake during the mapping of glaciers, snow patches and rock glaciers. However, it is clear that the Argentinean glacier inventory tried to find a balance between what is on the one hand legally and on the other hand scientifically justifiable. In addition, the water content of the features shows that glaciers and the periglacial environment in this region play an important role as a water resource, since the conflict takes place in a rather arid area

"Kometensplitter einer Biographie" & die vielstimmige Beweglichkeit der Kunst. Autofiktionales Erzählen in Felicitas HOPPEs Hoppe

In this thesis I examine in how far, or to which degree, the concept of autofiction can be applied to Felicitas Hoppe’s text Hoppe (2012). Since the coinage of the term ‘autofiction’ by Serge Doubrovsky in the 1970s, there have been many discussions and redefinitions of this possible genre. The discussions include questions regarding definitions of autobiography and the novel within the field of literary theory, as well as the depiction of fact and fiction. Moreover, they ask in how far the knowledge of the impossibility of capturing ‘reality’ via language technically turns any autobiography into autofiction. Various positions regarding these debates, including the thoughts and positions of scholars such as Philippe Lejeune, Serge Doubrovsky, Martina Wagner- Egelhaaf, and Frank Zipfel, are represented in the first part of this thesis. In the sections that follow, I show how Felicitas Hoppe’s Hoppe is a text that intertwines ‘factuality’ and ‘fiction’ in a way that it can be interpreted as either or indeed simultaneously both genres (doppeltes Leseangebot) in the sense of Frank Zipfel. I point out that from the paratextual features of Hoppe to the tripartite fission of ‘Hoppe’ – including the author HOPPE, the narrator ‘fh’, and the protagonist Felicitas Hoppe – the text allows and asks with its particular construction for new interpretations of identity and self-representation. Finally, I conclude with the assumption that Hoppe is a text that might not be completely captured with present available literary theories. However, the refusal of the text to being fully assigned to any one particular genre or typology remains one of the many strengths of Felicitas Hoppe’s Hoppe

Background resistivity model from seismic velocities

ABSTRACT We developed a methodology to estimate resistivities from seismic velocities. We applied known methods, including rock physics, depth trends, structural information, and uncertainty analysis. The result is the range of background resistivity models that is consistent with the known seismic velocities. We successfully tested the methodology with real data from the North Sea. These 2D or 3D background resistivity models yield a detailed insight into the background resistivity, and they are a powerful tool for feasibility studies. They could also serve as starting models or constraints in (iterative) forward modeling of electromagnetic data for the determination of subsurface resistivities

Bayesian estimation of resistivities from seismic velocities

I address the problem of finding a background model for the estimation of resistivities in the earth from controlled-source electromagnetic (CSEM) data by using seismic data and well logs as constraints. Estimation of resistivities is normally done by trial-and-error, in a process called “inversion”, by finding a model of the earth whose responses match the data to within an acceptable error; what comes out of the inversion is what is put into the model by the geophysicist: it does not come out of the data directly. The premise underlying this thesis is that an earth model can be found that satisfies not only the CSEM data but also the seismic data and any well logs. I present a methodology to determine background resistivities from seismic velocities using rock physics, structural constraints, and depth trends. The physical parameters of the seismic wave equation are different from those in the electromagnetic diffusion equation, so there is no direct link between the governing equations. I therefore use a Bayesian framework to incorporate not only the errors in the data and our limited knowledge of the rock parameters, but also the uncertainty of our chosen and calibrated velocity-to-resistivity transform. To test the methodology I use a well log from the North Sea Harding South oil and gas field to calibrate the transform, and apply it to seismic velocities of the nearby Harding Central oil and gas field. I also use short-offset CSEM inversions to estimate the electric anisotropy and to improve the shallow part of the resistivity model, where there is no well control. Three-dimensional modelling of this resistivity model predicts the acquired CSEM data within the estimated uncertainty. This methodology makes it possible to estimate background resistivities from seismic velocities, well logs, and other available geophysical and geological data. Subsequent CSEM surveys can then focus on finding resistive anomalies relative to this background model; these are, potentially, hydrocarbon-bearing formations

Interference phenomena in the JP=1/2−J^P=1/2^--wave in η\eta photoproduction

The recent precise experimental results for the photoproduction of $\eta$-mesons off the neutron measured with the Crystal Ball/TAPS calorimeter at the MAMI accelerator have been investigated in detail in the framework of the Bonn-Gatchina coupled channel model. The main result is that the narrow structure observed in the excitation function of $\gamma n \rightarrow n\eta$ can be reproduced fully with a particular interference pattern in the $J^P=1/2^-$ partial wave. Introduction of the narrow resonance $N(1685)$ with the properties reported in earlier publications deteriorates the quality of the fit.Comment: 10 pages, 13 figures, accepted for publication in EPJ

Investigation of the anomaly in eta-photoproduction off the neutron

Quasi-free photoproduction of eta-mesons off the neutron and off the proton has been studied using a deuterium target and bremsstrahlung photons produced by MAMI-C with incident energies up to 1.5 GeV. The eta-mesons were detected in coincidence with the recoil nucleons thus a fully exclusive measurement was performed. Preliminary results show a bump-like structure in the excitation function for the neutron close to W $\approx$ 1675 MeV which is not seen for the proton. Considering the experimental resolution and using a Breit-Wigner fit the width of this structure was approximated below 50 MeV.Comment: oral contribution to the workshop on physics of the excited nucleon - NSTAR 2009, Beijing, April 200

Quasi-free Photoproduction of η-Mesons off 2H and 3He

In this work, we are presenting a combination of two preliminary results for quasi-free photoproduction of η-mesons from the liquid deuterium and 3He targets for incident photon energies from threshold up to 1.4 GeV. The experiments were performed at the Mainz MAMI electron accelerator, using the Glasgow tagged photon facility. Decay photons of the η-mesons and the recoil nucleons were detected with an almost 4π covering electromagnetic calorimeter combining the Crystal Ball and TAPS detectors. The data from both targets show a narrow structure in the excitation function of γ + n → n + η. The results from the two measurements are consistent within the expected effects from nuclear Fermi motion

Ocean Bottom Seismometer Clock Correction using Ambient Seismic Noise

Ocean-bottom seismometers (OBSs) are equipped with seismic sensors that record acoustic and seismic events at the seafloor, which makes them suitable for investigating tectonic structures capable of generating earthquakes offshore. One critical parameter to obtain accurate earthquake locations is the absolute time of the incoming seismic signals recorded by the OBSs. It is, however, not possible to synchronize the internal clocks of the OBSs with a known reference time, given that GNSS signals are unable to reach the instrument at the sea bottom. To address this issue, here we introduce a new method to synchronize the clocks of large-scale OBS deployments. Our approach relies on the theoretical time-symmetry of time-lapse (averaged) crosscorrelations of ambient seismic noise. Deviations from symmetry are attributed to clock errors. This implies that the recovered clock errors will be obscured by lapse crosscorrelations' deviations from symmetry that are not due to clock errors. Non-uniform surface wave illumination patterns are arguably the most notable source which breaks the time symmetry. Using field data, we demonstrate that the adverse effects of non-uniform illumination patterns on the recovered clock errors can be mitigated by means of a weighted least-squares inversion that is based on station-station distances. In addition, our methodology permits the recovery of timing errors at the time of deployment of the OBSs. This error can be attributed to either: i) a wrong initial time synchronization of the OBS or ii) a timing error induced by changing temperature and pressure conditions while the OBS is sunk to the ocean floor. The methodology is implemented in an open-source Python package named OCloC, and we applied it to the OBS recordings acquired in the context of the IMAGE project in and around Reykjanes, Iceland. As expected, most OBSs suffered from clock drift. Surprisingly, we found incurred timing errors at the time of deployment for most of the OBSs

Proton Zemach radius from measurements of the hyperfine splitting of hydrogen and muonic hydrogen

While measurements of the hyperfine structure of hydrogen-like atoms are traditionally regarded as test of bound-state QED, we assume that theoretical QED predictions are accurate and discuss the information about the electromagnetic structure of protons that could be extracted from the experimental values of the ground state hyperfine splitting in hydrogen and muonic hydrogen. Using recent theoretical results on the proton polarizability effects and the experimental hydrogen hyperfine splitting we obtain for the Zemach radius of the proton the value 1.040(16) fm. We compare it to the various theoretical estimates the uncertainty of which is shown to be larger that 0.016 fm. This point of view gives quite convincing arguments in support of projects to measure the hyperfine splitting of muonic hydrogen.Comment: Submitted to Phys. Rev.