The Value of a Statistical Injury: New Evidence from the Swiss Labor Market

We study the monetary compensation for non-fatal accident risk in Switzerland using the number of accidents within cells defined over industry x skill-level of the job and capitalizing on the partial panel structure of our data which allows us to empirically isolate the wage component specific to the employer. Our results show that using accident risk at a lower level of aggregation, using narrower samples of workers, and using the wage component that is specific to the firm all yield higher estimates of risk compensation. Our preferred estimate gives an estimate of about 36,000 Swiss francs per prevented injury per year.Compensating wage differentials, value of a statistical injury, risk measurement

Nonlinear Zeeman Effects in the Cavity-Enhanced Emission of Polarised Photons

We theoretically and experimentally investigate nonlinear Zeeman effects within a polarised single-photon source that uses a single 87Rb atom strongly coupled to a high finesse optical cavity. The breakdown of the atomic hyperfine structure in the D2 transition manifold for intermediate strength magnetic fields is shown to result in asymmetric and, ultimately, inhibited operation of the polarised atom-photon interface. The coherence of the system is considered using Hong-Ou-Mandel interference of the emitted photons. This informs the next steps to be taken and the modelling of future implementations, based on feasible cavity designs operated in regimes minimising nonlinear Zeeman effects, is presented and shown to provide improved performance.Comment: 12 pages, 8 figure

Polarisation oscillations in birefringent emitter-cavity systems

We present the effects of resonator birefringence on the cavity-enhanced interfacing of quantum states of light and matter, including the first observation of single photons with a time-dependent polarisation state that evolves within their coherence time. A theoretical model is introduced and experimentally verified by the modified polarisation of temporally-long single photons emitted from a $^{87}$Rb atom coupled to a high-finesse optical cavity by a vacuum-stimulated Raman adiabatic passage (V-STIRAP) process. Further theoretical investigation shows how a change in cavity birefringence can both impact the atom-cavity coupling and engender starkly different polarisation behaviour in the emitted photons. With polarisation a key resource for encoding quantum states of light and modern micron-scale cavities particularly prone to birefringence, the consideration of these effects is vital to the faithful realisation of efficient and coherent emitter-photon interfaces for distributed quantum networking and communications.Comment: 9 pages, 5 figures including Supplemental Materia

Income Imputation in Longitudinal Surveys: A Within-Individual Panel-Regression Approach

Unlike for cross-sectional data, there is only little research on income imputation for longitudinal data. The current best practise is the Little and Su (L&S) method, which is based on individual-specific mean income over time. While the L&S method performs well for cross-sectional analysis, longitudinal estimates such as income mobility or fixed effects models tend to be biased. We argue that this bias arises from the L&S method treating within-individual variance – which is the basis of longitudinal analysis – as random. In this paper, we present an imputation approach, which uses information available in the missing wave which correlated with a changed income. The expected value is the sum of the individual mean across the observed waves and the within-individual deviance for the wave with missing information. We evaluate this new approach using employment income from the Swiss Household Panel and allow data to be missing at random and not at random. We compare different variants of this approach to the listwise deletion and the L&S method. The missingness mechanisms are estimated on the basis of an external data source containing both registry information and survey questions on income. We use performance criteria proposed in previous evaluations of longitudinal imputation methods. As an additional criterion, we consider the performance in application examples, by testing the bias of regression coefficients in typical longitudinal multivariate regression models. Our results indicate no systematic difference between imputation methods for cross-sectional criteria and for multivariate regression models, but a better performance of the new approach for longitudinal criteria. In applied fixed effects models, no imputation generally reduce bias compared to listwise deletion

Binding free energy calculations and molecular dynamics simulations on complexes of viral proteases with their ligands

Ein Ziel der biomolekularen Modellierung ist die Berechnung der Affinität deltaG von Liganden an Proteine, insbesondere Enzyme. Das Spektrum der Methoden, die zu diesem Zweck entwickelt wurden, reicht von theoretisch genauen aber aufwändigen Verfahren zu einfachen, eher qualitativen Verfahren. Während letztere häufig empirische Scoring-Funktionen und eine einzelne Struktur als Eingabe verwenden, wird für kompliziertere Methoden der möglichst vollständige Konformationsraum eines Protein-Ligand-Komplexes benötigt. Dieser wird mit Sampling-Verfahren wie der Molekulardynamik (MD) durchmustert. In dieser Promotionsarbeit sollten Verfahren zur Berechnung von deltaG, insbesondere Varianten der Molecular Mechanics Poisson-Boltzmann Surface Area (MMPBSA) Methode, getestet und nach Möglichkeit weiterentwickelt werden. Desweiteren sollte die Auswirkung bestimmter Resistenzmutationen auf Struktur und Dynamik von Proteinen mit unterschiedlichen Maßen aus MD Simulationen heraus erfasst werden. Der erste Schritt der quantitativen Modellierung mit MD ist die Beschreibung der Moleküle durch die Parametrisierung eines Kraftfelds. Anhand des sulfatierten Tyrosins wurde eine solche molekulare Parametrisierung für ein Nicht-Standard-Molekül durchgeführt. Sodann wurden Varianten der tendenziell weniger aufwändigen MMPBSA-Methode getestet im Hinblick auf ihre Konvergenz und ihre Eignung zur Bestimmung genauer deltaG-Werte oder zumindest verschiedene Enzym-Ligand-Komplexe in eine richtige Rangfolge gemäß ihrer deltaG-Werte zu bringen. Die Varianten unterscheiden sich durch verschiedene Solvatisierungsmodelle und Methoden zur Berechnung der Entropie. Als molekulares Referenzsystem wurden Mutanten der HIV Protease im Komplex mit Wirkstoffen verwendet, da es hierzu experimentelle Daten gibt, mit denen die berechneten Werte verglichen werden können. Am anderen Ende des methodischen Spektrums liegt die aufwändige Thermodynamische Integration (TI). Bei einer guten Kraftfeldparametrisierung sollte TI in der Lage sein, deltaG-Effekte in der Größenordnung weniger kJ/mol quantitativ zu bestimmen. Dies wurde anhand der Mutante L76V der HIVProtease, die für einige Wirkstoffe zu einer Resensitivierung (erhöhte Affinität) führt, getestet. Schließlich sollten MD-Simulationen verwendet werden, um die molekularen Effekte von Mutationen der NS3/4A-Protease des humanen Hepatitis C Virus auf die Bindung von Liganden (Substrat, Inhibitoren) zu verstehen.A major aim of biomolecular modelling is the calculation of binding affinities deltaG of ligands to proteins, especially enzymes. The spectrum of methods that has been developed for this task ranges from theoretically exact but expensive to more simple and qualitative ones. While the latter are often empirical scoring functions using one single structure as an input, the more complex methods require the preferably complete conformational space of a protein-ligand complex which can be sampled using methods such as molecular dynamics (MD). The intention of this thesis was to test and further develop methods for the calculation of deltaG, in particular variants of the molecular mechanics Poisson-Boltzmann surface area (MMPBSA) method. Furthermore, the effects of specific resistance mutations on the structure and dynamics of proteins should be determined using different metrics on MD simulation data. The first step to quantitative modelling using MD is the description of the molecules by parameterizing a forcefield. Such a molecular parameterization was performed for the non-standard amino acid sulpho-tyrosine. Subsequently, variants of the less expensive MMPBSA method were tested with regard to their ability to converge and determine deltaG estimates or at least establish the correct ranking of deltaG values for a set of enzyme-ligand complexes. Different solvation models and procedures to calculate the entropy have been used. As a molecular reference system, mutants of the HIV protease complexed with inhibitors were used. For these systems, experimental data are available to which the calculated values can be compared. At the other end of the methodological spectrum is the more expensive thermodynamic integration (TI). With a proper forcefield parameterization, TI should be able to quantitatively determine deltaG effects in the order of a few kJ/mol. This was tested on the HIV protease mutation L76V which is known to lead to a resensitivation (increased affinity) for some drugs. Eventually, MD simulations were used to understand the molecular effects of mutations of the NS3/4A protease, an enzyme of the human hepatitis C virus, on the binding of ligands (substrate, inhibitors)

Altered carbon cycling and trace-metal enrichment during the late Valanginian and early Hauterivian

Abstract.: Carbonates of Valanginian age deposited in the Tethys and Atlantic Oceans show a distinct positive δ13C excursion (Δ δ13C = 1.5‰-2‰) in sections of the neritic, hemipelagic, and pelagic environment. This excursion records a major climate-induced perturbation of the global carbon system. The δ13C excursion is accompanied by enrichments in manganese (Mn) and iron (Fe). The correlation of the δ13C excursion with trends in Mn and Fe contents reflects changes in Valanginian paleoceanography and climate. Fe enrichment occurs mainly in terrestrial, platform, and shelf regions. In a basinal direction the Fe content decreases, whereas the Mn/Fe ratio increases. An increase in sedimentary Mn and Fe concentrations is related to elevated continental weathering rates and to widespread dys- or anoxia that favored metal deposition in Valanginian sediments. Various oceanographic changes (e.g., expansion of oxygen-minimum zones) resulting from increased continental runoff led to a strong remobilization and focused reprecipitation of metals in the oceans of the Valanginian stag