Essays on Minimum Wages, Labour Supply and Public Finances

Diese Dissertation umfasst drei Aufsätze zu Mindestlöhnen, zum Arbeitsangebot sowie zu öffentlichen Finanzen. Der Fokus liegt auf den Entwicklungen in Deutschland innerhalb der letzten zwei Jahrzehnte. Der erste Aufsatz untersucht Beschäftigungseffekte des Mindestlohns in einem Modell der Sucharbeitslosigkeit. Das Modell bildet Heterogenität auf Arbeitnehmer- und Arbeitgeberseite ab und schränkt die Richtung der Beschäftigungseffekte ein. Es erlaubt eine unterschiedliche Frequenz der Stellensuche von Beschäftigten und Arbeitslosen und modelliert die Rekrutierungsintensität der Unternehmen. Die Ergebnisse zeigen, dass die Arbeitslosigkeit eine nicht-monotone Funktion des Mindestlohns ist. Die Auswirkungen von verschiedenen Mindestlöhnen unterscheiden sich stark nach Arbeitsmarktsegmenten. Der zweite Aufsatz befasst sich mit Trends im Arbeitsangebotsverhalten in Deutschland. Dazu werden diskrete Wahlmodelle des Arbeitsangebots für die Jahre von 1998 bis 2018 geschätzt. Die implizierten Arbeitsangebotselastizitäten haben in den letzten zwei Jahrzehnten zugenommen, insbesondere für Paare und für alleinstehende Männer. Eine Zerlegungsanalyse zeigt, dass Veränderungen in der Demografie nur eine geringe Rolle bei der Verschiebung der Eigen- und Kreuzlohnelastizitäten von Männern spielen, da der größte Teil der Veränderungen durch Präferenzen oder Arbeitsmarktrestriktionen bedingt ist. Bei Frauen hingegen spielen demografische Veränderungen eine größere Rolle für den Anstieg der Elastizitäten. Der dritte Aufsatz befasst sich mit den deutschen Staatsfinanzen sowie mit Reformen aufgrund der Finanzkrise 2008/2009. Der Aufsatz stellt die makroökonomische Situation und die Entwicklung der Krise in Deutschland dar und beleuchtet die Bedeutung für die öffentlichen Finanzen. In dem Aufsatz werden zudem die Verteilungswirkungen der Reformen im Steuer- und Transfersystem mithilfe von Mikrosimulationen untersucht.This dissertation consists of three essays on the minimum wage, labour supply, and public finances. The selected essays focus on the German experience and developments over the last two decades. The first essay is an analysis of unemployment effects of the German minimum wage in an empirical equilibrium job search model. The estimated model with worker and firm heterogeneity does not restrict the sign of employment effects a priori; it allows for different job offer arrival rates for the employed and the unemployed and lets firms optimally choose their recruiting intensity. Results show that unemployment is a non-monotonic function of the minimum wage level, and effects differ strongly by labour market segment. The second essay is on the topic of labour supply elasticities in Germany. In order to analyse recent trends in labour supply in Germany, a static discrete choice model of unitary household labour supply is estimated for each year 1998 to 2018. Findings are that own-wage labour supply elasticities implied by the models have increased over the last two decades, especially for couples, and for single males. A decomposition analysis shows that compositional changes in demographics play only a minor role in the shift in males' own- and cross-wage elasticities, since most of the changes in elasticities are driven by preferences or labour market restrictions. For females, changes in composition play a bigger role in the rise of elasticities. The third essay reviews German public finances through the financial crisis 2008/2009. The essay starts with a presentation of the macroeconomic situation and how the crisis unfolded in Germany, before focusing on the situation of the public finances. Finally, the distributional effects of policy responses to the financial crisis are analysed on the individual level using microsimulation

Sîn City : notes on the moon god of Ḫarrān/Carrhae in the Partho-Roman period

Today the city of Ḫarrān/Carrhae is mainly known for the famous battle, in which the Roman general Crassus was defeated by a Parthian army in 53 BCE. However, Ḫarrān was also one of the most important religious centres of North Mesopotamia. Since the Bronze Age, the moon god Sîn of Ḫarrān was popular in the wider region, and it is well known that the late Assyrian and Baby- lonian kings supported the cult and rebuilt the temple of Sîn. Archaeological evidence and written sources attest to the great popularity of Sîn of Ḫarrān at that time. Much less is known about the development of the cult in the subsequent periods, but the evidence assembled in this paper in- dicates that it continued to thrive. An important but so far largely ignored source for the study of Sîn are coins, which were minted at Ḫarrān in the second and third century CE. They suggest that some distinctive features of the Iron Age cult still existed in the Roman period. Most important in this regard is the predominance of aniconic symbolism. A cult standard, a crescent on a globe with tassels mounted on a pole, continued to be the main of representation of the god. In addition, two versions of an anthropomorphic image of the god can be traced in the coinage of Ḫarrān. The first shows him as an enthroned mature man. It is based on the model of Zeus, but his attributes iden- tify the god as Sîn. The second version portrays him as a youthful, beardless god. Late antique sources frequently mention that the people of Ḫarrān remained attached to pagan religion, but the veracity of these accounts must be questioned. A reassessment of the literary and archaeological evidence suggests that the accounts of a pagan survival at Ḫarrān are hyperbolic and exacer ated by negative sentiments towards Ḫarrān among writer from the neighbouring city of Edessa

New universality class for the fragmentation of plastic materials

We present an experimental and theoretical study of the fragmentation of polymeric materials by impacting polypropylene particles of spherical shape against a hard wall. Experiments reveal a power law mass distribution of fragments with an exponent close to 1.2, which is significantly different from the known exponents of three-dimensional bulk materials. A 3D discrete element model is introduced which reproduces both the large permanent deformation of the polymer during impact, and the novel value of the mass distribution exponent. We demonstrate that the dominance of shear in the crack formation and the plastic response of the material are the key features which give rise to the emergence of the novel universality class of fragmentation phenomena.Comment: 4 pages, 4 figures, appearing in Phys. Rev. Let

Downregulation of Tumor Necrosis Factor Expression in the Human Mono-Mac-6 Cell Line

Mono-Mac-6 cells, but not U937 cells, can be Induced to rapidly express tumor necrosis factor (TNF) mRNA and protein when triggered with Ilpopolysaccharlde (LPS) at 1 pg/mI. Preincubatlon of the cells for 3 d with low amounts of LPS (10 ng/mI) results In nearly complete suppression of TNF secretion. This downreguiatlon appears to occur at the pretranslational level since specIfIc mRNA is virtually undetectable under these conditions. By contrast, the same prelncubatlon with 10 ng/mI LPS results in enhanced phagocytosls (28.6-67.2% for Staphylococcus aureus), demonstrating that not all monocyte functions are suppressed. While these results show that only stringent exclusion of LPS from culture media allows for Induction of TNF In the Mono-Mac-6 cell line, the pronounced effect of LPS preincubatlon may also provide a suitable model with which to study the mechanisms of LPS-lnduced desensitizatIon