Three Essays on Markets with Constrained Price Mechanisms

This dissertation consists of three independent chapters. Their common topic is that they analyze markets in which the prices are not free to adjust, either because of price caps or because of price stickiness. In the first chapter, I analyze the effects of asymmetric price caps in a duopoly; a special case of which is that only one firm has a price cap. To do so, I incorporate asymmetric price caps into a quantity competition model. A (non-price) rationing rule determines a firm's inverse residual demand function in the presence of price caps, and the price cap makes the inverse residual demand function flat above the price cap. If only one price cap binds, asymmetric price caps induce a trade-off: When adjusting the binding price cap to increase the total quantity, the production gets more unequal across firms, that is, more inefficient. In the second chapter, Fabian Schmitz and I explain why and how non-compete clauses may be used to undermine the intended effect of minimum wages. Many low-wage workers in the United States have signed non-compete clauses, forbidding them to work for competitors. Empirical research has found a positive correlation between the level of the minimum wage and the prevalence of non-compete clauses. We explain this with moral hazard: By incentivizing more effort, non-compete clauses transfer utility from the agent to the principal. If the minimum wage is sufficiently high, the agent would get a rent without non-compete clauses. With a non-compete clause, the principal can extract this rent at some efficiency loss. In the third chapter, Maximilian Weiß and I conduct and evaluate a survey about price stickiness among German hairdressers. Surveying managers is a controversial method for finding out why prices are sticky because the results are often too noisy to be useful. By focusing on a single market and asking about the reactions to recent shocks, we reduce the noise in our survey. We find that the desire to retain regular customers is the main source of price stickiness. Furthermore, we find suggestive evidence for the importance of the customers' trust in the firm's commitment to fair pricing

Non-equilibrium dynamics of a system with Quantum Frustration

Using flow equations, equilibrium and non-equilibrium dynamics of a two-level system are investigated, which couples via non-commuting components to two independent oscillator baths. In equilibrium the two-level energy splitting is protected when the TLS is coupled symmetrically to both bath. A critical asymmetry angle separates the localized from the delocalized phase. On the other hand, real-time decoherence of a non-equilibrium initial state is for a generic initial state faster for a coupling to two baths than for a single bath.Comment: 22 pages, 9 figure

A Dynamic North-South Model of Demand-Induced Product Cycles

This paper presents a dynamic North-South general-equilibrium model where households have non-homothetic preferences. Innovation takes place in a rich North while norms in a poor South imitate products manufactured in North. Introducing non-homothetic preferences delivers a complete international product cycle as described by Vernon (1966), where the different stages of the product cycle are not only determined by supply side factors but also by the distribution of income between North and South. We ask how changes in Southern labor productivity, South's population size and inequality across regions affects the international product cycle. In line with presented stylized facts about the product cycle we predict a negative correlation between adoption time and per capita incomes

A Dynamic North-South Model of Demand-Induced Product Cycles

This paper presents a dynamic North-South general equilibrium model with non- homothetic preferences. Innovation takes place in the rich North while firms in the poor South at random imitate products manufactured in the North. The model is able to generate endogenous product cycles as described by Vernon (1966) where the different stages of the product cycle are not only determined by supply side factors but also by the distribution of income between North and South. We simulate comparative statics results of changes in Southern labor productivity, changes in inequality across regions, and changes in the savings rate. We further provide suggestive evidence for the product cycle stages

Insufficient sterilisation procedures and transmission of pathogens in developing countries

No Abstract

Occurrence of social wasps (Hymenoptera: Vespidae) in farming of organic tobacco (Nicotiana tabacum L.) in south of Brazil

This work aims to recognize and record the occurrence of species of social wasps (Polistinae) in organic tobacco crops, as well as to point out possible species that may be used in future biological control programs. The research was conducted in Virginia-type tobacco farming with organic management in two regions in south of Brazil. The collections were carried out with Malaise trap, during the harvests 2008/2009, 2009/2010 and 2010/2011. A total of 2.738 wasps, from which 23 species distributed in six genera was collected. Polistes was the most diverse genus (8 species), followed by Polybia, Mischocyttarus, Agelaia, Bachygastra and Protonectarina. Polybia scutellaris was the most abundant species, being considered eudominant. Agelaia multipicta and Polybia sericea with are also among the most abundant. This information is relevant for the insertion of social wasps with potential agents in the biological control of tobacco pests

Thermo-cyclically operated metal oxide gas sensor arrays for analysis of dissolved volatile organic compounds in fermentation processes: Part II – Quasi online monitoring in biogas fermentation

This study presents a quasi-online method for monitoring of dissolved volatile fatty acids (VFAs) in biogas fermentation processes with a carrier gas probe by use of thermo-cyclically operated metal oxide gas sensor arrays. Each of the two sensor arrays comprises a pure SnO$_2$ and three different SnO$_2$/additive-composites (additives: alumina, YSZ, NASICON) but differ by SnO$_2$ synthesis routes, namely Flame Spray Pyrolysis (FSP) and Sol-Gel (SG) technique, respectively. This allowed comparative studies of the influence of layer morphology on VFA sensing characteristics. For sensitive determination of the dissolved VFAs besides high concentrations of biogas components like CO or CH$_4$, first a pre-treatment routine of the fermentation sample was introduced to remove those physically dissolved gases without losing VFAs. The Conductance-over-Time-Profiles (CTPs) of eight different sensing layers were measured simultaneously at exposure to the gases extracted from the fermentation sample at different pH conditions. Almost all the investigated SnO$_2$/additive-composites show CTP-features clearly correlating with the undissociated VFA even at concentrations below 120 ppm as referenced by GC-analysis. The lower detection limit is well below inhibitory concentration for fermentation processes. As expected, most pronounced CTPs representing actual VFAs situation were measured at pH 3, well below the pKa of the VFAs. The FSP-layers highlighted clearly better sensitivity and CTP specificity of higher quality compared to SG-layers. Among the SnO$_2$/additives, the CTP-features of the SnO$_2$(FSP)/NASICON and SnO$_2$(SG)/NASICON layers showed the best specificity to acetic and propionic acid. For the first time, quasi-online analysis of VFAs using metal oxide gas sensors for early warning of VFA-development in biogas fermentation processes was demonstrated

Effect of Habrobracon hebetor (Hymenoptera: Braconidae) Release on Moth Infestation in Stored Tobacco

During the storage period of dry tobacco and its derivatives, insect pests such as species of Ephestia Guenée (Lepidoptera: Pyralidae), popularly known as moths, cause damage to the product, being controlled mainly with physical practices and synthetic chemicals, although with limitations on their use and results. Some biological control agents, such as the parasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae), have the potential to control these pests. This study aimed to evaluate the effect of H. hebetor release in tobacco farms and industrial warehouses, on the infestation of Ephestia spp. adults. Parasitoids were released in tobacco farmers and tobacco industry warehouses between 2016-2018, comprising two years/crop seasons. Each release consisted of 1,000 parasitoids (four times) in tobacco farmers warehouses (70 m2 ) and 30,000 (five times) in tobacco industry warehouses (8,000 m2 ). Pheromone-baited sticky traps were used to weekly monitor the average number of adults of Ephestia spp. in warehouses with (WP) and without parasitoid release (NP). The average number of adults of Ephestia spp. captured in the traps in WP environments at farmers and industry level was significantly lower than the average captured in NP from the third and fifth weeks. In the following weeks, the averages of Ephestia spp. were always significantly lower in the WP environments until the end of monitoring. Therefore, the use of H. hebetor for moth control should be considered as part of a biological control program in stored tobacco environments