Spin-base-invariant formulation of Hilbert-Palatini gravity

In dieser Arbeit leiten wir eine neue Formulierung der Allgemeinen Relativitätstheorie ab, welche koordinatenabhängige Dirac Matrizen und einen verallgemeinerten Spin-Zusammenhang als Freiheitsgrade verwendet und die volle Spin-Basis-Invarianz - eine Symmetrie aller fermionischen Materie in der Natur - bewahrt. Die koordinatenabhängigen Dirac Matrizen werden dabei durch eine verallgemeinerte Clifford Algebra definiert, welche lokal postuliert wird. Diese Dirac Matrizen sind die natürlichen Variablen des so genannten Spin-Basen Formalismus, der es erlaubt, Spinore in gekrümmten Raumzeiten zu definieren, ohne ein spezielles Koordinatensystem einzuführen zu müssen, d.h. ein Vielbein-Feld ist nicht erforderlich. In der Verallgemeinerung des Spin-Zusammenhangs finden wir einen uneingeschränkten Freiheitsgrad, der neben der explizit implementierten Spin-Basis-Symmetrie eine weitere Symmetrie der neuen Formulierung aufdeckt. Weiter untersuchen wir in der Krümmung quadratische Terme, aus denen ein kinetischer Term für diesen unbeschränkten Freiheitsgrad hervorgeht, der ihn zu einem dynamischen Bestandteil der Theorie macht.In this thesis we derive a novel formulation of General Relativity that uses curved (spacetimedependent) Dirac matrices and generalized spin connections as degrees of freedom and preserves full spin-base invariance - a symmetry of all fermionic matter sectors in nature. The curved Dirac matrices are thereby defined by virtue of a generalized Clifford algebra, which is postulated to hold locally. These Dirac matrices are the natural variables of the so called spin-base formalism, which allows to define spinors in curved spacetimes without introducing a coframe, i.e. a vielbein field is not required. In the generalization of the spin connection, we find an unconstrained degree of freedom, which uncovers a new symmetry of the novel formulation aside from the spin-base symmetry explicitly implemented. We investigate terms quadratic in the curvature, which give rise to a kinetic term for this unconstrained degree of freedom promoting it to a dynamical constituent of the theory

Conciliating to avoid moral scepticism

A common worry about moral conciliationism is that it entails at best uncertainty about many of our moral beliefs and at worst epistemological moral scepticism. Against this worry, I argue that moral conciliationism saves us from epistemological moral scepticism and enables us to be confident in many of our moral beliefs. First, I show that only taking disagreements seriously as a threat to our beliefs allows us to utilise agreements in support of our beliefs (call this symmetry). Next, I argue that utilising moral agreements as an epistemic resource allows moral conciliationism to resist the potentially worrisome reduction in confidence of our moral beliefs. Taking the relevance of moral agreement into account, I argue that it is anti-conciliationism that must meet the challenge of epistemological moral scepticism. For this, I suggest that moral inquiry is best understood as a collective endeavour. If so, then agreement on our moral judgments is required to justify the confidence we have in many of our moral beliefs. However, by symmetry, this appeal is possible only if one accepts the conciliatory attitude towards disagreements. Hence, accepting, rather than rejecting moral conciliationism, is the way out of moral scepticism.Publisher PDFPeer reviewe

Pseudogap suppression by competition with superconductivity in La-based cuprates

We carried out a comprehensive high-resolution angle-resolved photoemission spectroscopy (ARPES) study of the pseudogap interplay with superconductivity in La-based cuprates. The three systems La2−xSrxCuO4, La1.6−xNd0.4SrxCuO4, and La1.8−xEu0.2SrxCuO4 display slightly different pseudogap critical points in the tem- perature versus doping phase diagram. We studied the pseudogap evolution into the superconducting state for doping concentrations just below the critical point. In this setting, near optimal doping for superconductivity and in the presence of the weakest possible pseudogap, we uncover how the pseudogap is partially suppressed inside the superconducting state. This conclusion is based on the direct observation of a reduced pseudogap energy scale and re-emergence of spectral weight suppressed by the pseudogap. Altogether these observations suggest that the pseudogap phenomenon in La-based cuprates is in competition with superconductivity for antinodal spectral weight.J.K., C.L., K.v.A., Q.W., K.K., M.H., W.R.P., N.C.P., and J.C. acknowledge support from the Swiss National Science Foundation (Projects No. 200021_188564 and No. 200021_- 185037). J.K. is supported by a Ph.D. fellowship from the German Academic Scholarship Foundation. Y.S. was sup- ported by the Wenner-Gren foundation. J.-S.Z. was supported by an NSF grant (MRSEC DMR-1720595). This work was performed at the SIS at the Swiss Light Source and I05 at the Diamond Light Source. This work was carried out with the support of Diamond Light Source, instrument I05 (Proposals No. SI 27768 and No. SI 10550).Center for Dynamics and Control of Material

Moral inquiry : we're all in this together

Moral inquiry is often thought of as an individualistic enterprise. This is in large part because morality not only seems to require doing the right thing, but being in touch with moral reality in the right way: to act well, it is necessary to ground our actions on an insight into moral reasons—reasons we can only understand when we inquire for ourselves. In this dissertation, I defend a picture of moral inquiry according to which such inquiry is fundamentally social: we are not alone when it comes to making moral decisions. In particular, I argue that the conception of moral inquiry as an individualistic enterprise wrongly delegitimises a central resource of moral inquiry, moral testimony. To this end, I first argue that moral agreement is of crucial justificatory value in moral inquiry. I then go on to address some worries connected to moral testimony, arguing that reliance on moral testimony is not intrinsically wrong and indeed oftentimes permissible if not required of us. I complement this with a discussion of moral expertise, arguing that the search for moral experts has often been too focused on theoretical knowledge. However, practical experience is a much more reliable way of identifying those we can rely on with respect to a particular moral issue. Lastly, I discuss one consequence this more social picture of moral inquiry has, namely that blame can not only be allocated to a wrongdoing agent, but also to those who guided the agent to that act. This concludes my contribution to the defence of a more social picture of moral inquiry. Overall, however, my aim is not to do away with the importance of being rightly connected to moral reality—it is just that the best connection to moral reality available is often not through ourselves, but through others."Throughout my enrolment in the PhD programme at the University of St Andrews and the University of Stirling, I received a generous stipend from the Philosophical Quarterly as well as travel bursaries from the Department of Philosophy and the Arché Philosophical Research Centre here in St Andrews. My stay at Harvard University was possible only due to its fellowship programme. I am grateful to all of these institutions for considering my endeavour worthwhile enough for their support."--Acknowledgment

The Corona crisis and the stability of the European banking sector A repeat of the Great Financial Crisis? Bertelsmann Stiftung Repair and Prepare Strengthening Europe May 2020.

The Corona crisis1 has had a devastating effect on the global economy and could end up being worse than the Great Financial Crisis (GFC). Some commentators have already suggested that the decline in economic activity could be the most marked for several centuries. Unlike the GFC, the Corona crisis was triggered by an external shock. Govern- ments responded to this shock by offering liquidity to the real economy, either directly or indirectly by guaranteeing new bank lending. So far European banks have weathered the storm but will they be able to withstand a prolonged economic down- turn? This paper suggests that the fortunes of European banking systems will depend on the economic recovery we experience. If we witness a “V-shaped” recovery as cur- rently forecast by the European Commission, for example, then banks in the majority of EU member states might be able to survive unscathed. The picture could look very dif- ferent if the recovery turns out to be more sluggish though. The paper suggests that capital ratios – one of the key benchmarks used to assess the stability of banking systems – could drop dramatically in a number of member states such as France and Spain to well below what super- visors generally consider to be “sound” even under stress conditions. With the situation looking less severe in other member states such as Germany or the Netherlands, this could renew political tensions seen last during the euro area sovereign debt crisis. The paper is structured as follows. Section “The Corona crisis” presents the latest economic forecasts and con- trasts the current crisis with the GFC. In Section “Could the Corona crisis undermine the financial stability of the Euro- pean banking sector?” the paper draws on the results of the 2018 EBA adverse stress test. Comparing the 2018 EBA adverse scenario with a plausible “ticked-shaped” recov- ery post-Corona, the paper presents illustrative impacts on capital ratios in a selected number of EU member states. Section “Concluding Comments” looks at the role of Euro- pean-wide policy responses to deal with the crisis and what the Corona crisis might mean for the future of the EU’s Banking Union and Capital Markets Union

Autorenschaft in postdramatischer Drameninszenierung

Die Arbeit versucht am Beispiel einer bestimmten Inszenierung aus dem Jahr 1993, Goethes Faust √1+2, das offensichtliche Spannungsverhältnis zwischen dem Begriff des postdramati-schen Theaters und dem künstlerischen Schaffensprozess an klassischen Dramentexten durch gemeinhin dieser Strömung zugerechneten Theatermachern zu beleuchten. Im Detail wird darauf eingegangen, welche Autorenkörperschaften an der Genese der fertigen Inszenierung beteiligt sind, von der Vorlage über die Inszenierung bis zur Rezeption. Zu diesem Zweck wird im Theorieteil der Arbeit der Dramenbegriff ebenso analysiert wie die semiotischen Strukturen, die im literarischen Text des Dramas wie im theatralischen Text der Inszenierung zum Tragen kommen; außerdem wird der Transformationsvorgang – der der Inszenierung zugrunde liegende ‚Übersetzungsvorgang‗ – anhand wesentlicher Merkmale betrachtet. Wei-terhin werden die spezifisch einzigartigen Eigenschaften des postdramatischen Theaters im Hinblick auf ihren semantisch-semiotischen Gehalt beleuchtet, sowie textuell-sprachliche und sonstige Spezifika dargelegt. Im weiteren Verlauf wird besagte Inszenierung detailliert analysiert und mit der Vorlage Goe-thes verglichen, um Charakteristika im Umgang mit den Figuren und der chronologischen Kontinuität aufzuzeigen. Ferner wird der in der Inszenierung verwendete Fremdtext betrach-tet, und in Bezug auf Herkunft, Einsatz und Bedeutung im Kontext der Inszenierung beleuch-tet. Außerdem wird auf die spezifische Rolle dieses Dramas im deutschsprachigen Literatur-kanon eingegangen, und die Auswirkungen auf die Inszenierung betrachtet. Schließlich wird auf die Funktion des Rezipienten allgemein eingegangen, dessen ‚Mitarbeit‗ in postdramatischen Theaterarbeiten deutlich mehr gefordert wird als in historisch-tradierten Inszenierungen. Weiterhin wird versucht, anhand von ausgewählten Stellen der Inszenierung aufzuzeigen, wie eine solche Mitarbeit des Rezipienten aussehen kann und in wieweit dieser so selbst zum Autor wird

Olig2 regulates Sox10 expression in oligodendrocyte precursors through an evolutionary conserved distal enhancer

The HMG-domain transcription factor Sox10 is expressed throughout oligodendrocyte development and is an important component of the transcriptional regulatory network in these myelin-forming CNS glia. Of the known Sox10 regulatory regions, only the evolutionary conserved U2 enhancer in the distal 5′-flank of the Sox10 gene exhibits oligodendroglial activity. We found that U2 was active in oligodendrocyte precursors, but not in mature oligodendrocytes. U2 activity also did not mediate the initial Sox10 induction after specification arguing that Sox10 expression during oligodendroglial development depends on the activity of multiple regulatory regions. The oligodendroglial bHLH transcription factor Olig2, but not the closely related Olig1 efficiently activated the U2 enhancer. Olig2 bound U2 directly at several sites including a highly conserved one in the U2 core. Inactivation of this site abolished the oligodendroglial activity of U2 in vivo. In contrast to Olig2, the homeodomain transcription factor Nkx6.2 repressed U2 activity. Repression may involve recruitment of Nkx6.2 to U2 and inactivation of Olig2 and other activators by protein–protein interactions. Considering the selective expression of Nkx6.2 at the time of specification and in differentiated oligodendrocytes, Nkx6.2 may be involved in limiting U2 activity to the precursor stage during oligodendrocyte development

Regulation of Connective Tissue Growth Factor Expression Influences the Cell Viability In Human Trabecular Meshwork Cells

Connective tissue growth factor (CTGF) induces extracellular matrix (ECM) synthesis and contractility in human trabecular meshwork (HTM) cells. Both processes are involved in the pathogenesis of primary open-angle glaucoma. To date, little is known about regulation and function of CTGF expression in the trabecular meshwork (TM). Therefore, we analysed the effects of different aqueous humour proteins and stressors on CTGF expression in HTM cells. HTM cells from three different donors were treated with endothelin-1, insulin-like growth factor (IGF)-1, angiotensin-II, H2O2 and heat shock and were analysed by immunohistochemistry, real-time RT-PCR and Western blotting. Viability after H2O2 treatment was measured in CTGF silenced HTM-N cells and their controls. Latrunculin A reduced expression of CTGF by about 50% compared to untreated HTM cells, whereas endothelin-1, IGF-1, angiotensin-II, heat shock and oxidative stress led to a significant increase. Silencing of CTGF resulted in a delayed expression of αB-crystallin and in reduced cell viability in comparison to the controls after oxidative stress. Conversely, CTGF treatment led to a higher cell viability rate after H2O2 treatment. CTGF expression is induced by factors that have been linked to glaucoma. An increased level of CTGF appears to protect TM cells against damage induced by stress. The beneficial effect of CTGF for viability of TM cells is likely associated with the effects on increased ECM synthesis and higher contractility of the TM, thereby contributing to reduced aqueous humour outflow facility causing increased intraocular pressure

Revealing the Orbital Composition of Heavy Fermion Quasiparticles in CeRu2Si2

We present a resonant angle-resolved photoemission spectroscopy (ARPES) study of the electronic band structure and heavy fermion quasiparticles in CeRu2Si2. Using light polarization analysis, considerations of the crystal field environment and hybridization between conduction and f electronic states, we identify the d-electronic orbital character of conduction bands crossing the Fermi level. Resonant ARPES spectra suggest that the localized Ce f states hybridize with eg and t2g states around the zone center. In this fashion, we reveal the orbital structure of the heavy fermion quasiparticles in CeRu2Si2 and discuss its implications for metamagnetism and superconductivity in the related compound CeCu2Si2

Single-domain stripe order in a high-temperature superconductor

The coupling of spin, charge and lattice degrees of freedom results in the emergence of novel states of matter across many classes of strongly correlated electron materials. A model example is unconventional superconductivity, which is widely believed to arise from the coupling of electrons via spin excitations. In cuprate high-temperature superconductors, the interplay of charge and spin degrees of freedom is also reflected in a zoo of charge and spin-density wave orders that are intertwined with superconductivity. A key question is whether the different types of density waves merely coexist or are indeed directly coupled. Here we profit from a neutron scattering technique with superior beam-focusing that allows us to probe the subtle spin-density wave order in the prototypical high-temperature superconductor La$${}_{1.88}$$Sr$${}_{0.12}$$CuO$${}_{4}$$ under applied uniaxial pressure to demonstrate that the two density waves respond to the external tuning parameter in the same manner. Our result shows that suitable models for high-temperature superconductivity must equally account for charge and spin degrees of freedom via uniaxial charge-spin stripe fluctuations