Vertical Product Differentiation When Quality is Unobservable to Buyers

We analyze vertical product differentiation in a model where a good’s quality is unobservable to buyers before purchase, a continuum of quality levels is technologically feasible, and minimum quality is supplied under competitive conditions. After purchase the true quality of the good is revealed with positive probability. To provide firms with incentives to actually deliver promised quality, prices must exceed marginal cost. We derive sufficient conditions for these incentive constraints to determine equilibrium prices, and show that under certain conditions only one or both of the extreme levels of quality, minimum and maximum quality, are available in the market.experience goods, product differentiation, product quality, asymmetric information

Uncertainty in Spatial Duopoly with Possibly Asymmetric Distributions: a State Space Approach

In spatial competition firms are likely to be uncertain about consumer locations when launching products either because of shifting demograph- ics or of asymmetric information about preferences. Realistically distri- butions of consumer locations should be allowed to vary over states and need not be uniform. However, the existing literature models location uncertainty as an additive shock to a uniform consumer distribution. The additive shock restricts uncertainty to the mean of the consumers loca- tions. We generalize this approach to a state space model in which a vector of parameters gives rise to different distributions of consumer tastes in dif- ferent states, allowing other moments (besides the mean) of the consumer distribution to be uncertain. We illustrate our model with an asymmetric consumer distribution and obtain a unique subgame perfect equilibrium with an explicit, closed-form solution. An equilibrium existence result is then given for the general case. For symmetric distributions, the unique subgame perfect equilibrium in the general case can be described by a simple closed-form solution.Location, Product Differentiation, Uncertainty, Hotelling

Spacial Equilibrium in a State Space Approach to Demand Uncertainty

Firms are likely to be uncertain about consumer preferences when launching products. The existing literature models preference uncertainty as an additive shock to the consumer distribution in a characteristic space model. The additive shock only shifts the mean of the consumers' ideal points. We generalize this approach to a state space model in which a vector of parameters can give rise to dierent distributions of consumer tastes in dierent states, allowing other moments of the consumer density to be uncertain. An equilibrium existence result is given. In the case of symmetric distributions, the unique subgame-perfect equilibrium can be described by a simple closed-form solution.Location; Product Dierentiation; Uncertainty; Hotelling

Protein folding and the robustness of cells

The intricate intracellular infrastructure of all known life forms is based on proteins. The folded shape of a protein determines both the protein’s function and the set of molecules it will bind to. This tight coupling between a protein’s function and its interconnections in the molecular interaction network has consequences for the molecular course of evolution. It is also counter to human engineering approaches. Here we report on a simulation study investigating the impact of random errors in an abstract metabolic network of 500 enzymes. Tight coupling between function and interconnectivity of nodes is compared to the case where these two properties are independent. Our results show that the model system under consideration is more robust if function and interconnection are intertwined. These findings are discussed in the context of nanosystems engineering

A FRET-based method to study the activity of electron or oxygen transfer proteins and redox enzymes

This thesis centers around a novel fluorescence based method that allows to monitor the activity of redox enzymes and of electron (ET) or oxygen transfer proteins. It takes advantage of the fact that the absorption spectrum of the protein__s active site varies upon changing its redox state. This change can be translated into a change in the fluorescence intensity of a label that is covalently linked to the protein on the basis of F_rster Resonance Energy Transfer (FRET). With our method we could show that different redox proteins and enzymes can be studied down to the single molecule level. This exciting finding opens the door to the study of various redox enzymes and to monitor specific substances such as for example nitrite. Depending on the function of the enzyme under investigation a wide range of substrates can be monitored. Another example is the development of an oxygen sensor by employing proteins that are capable of binding oxygen. The findings presented in this thesis might be significant for applications in oxygen sensing and, more generally, in the fast growing field of biosensingFOM, Stichting voor Fundamenteel Onderzoek der MaterieUBL - phd migration 201

Multichannel Anomaly of the Resonance Pole Parameters Resolved

Inspired by anomalies which the standard scattering matrix pole-extraction procedures have produced in a mathematically well defined coupled-channel model, we have developed a new method based solely on the assumption of partial-wave analyticity. The new method is simple and applicable not only to theoretical predictions but to the empirical partial-wave data as well. Since the standard pole-extraction procedures turn out to be the lowest-order term of the proposed method the anomalies are understood and resolved.Comment: 5 page

On the connection between mutually unbiased bases and orthogonal Latin squares

We offer a piece of evidence that the problems of finding the number of mutually unbiased bases (MUB) and mutually orthogonal Latin squares (MOLS) might not be equivalent. We study a particular procedure which has been shown to relate the two problems and generates complete sets of MUBs in power-of-prime dimensions and three MUBs in dimension six. For these cases, every square from an augmented set of MOLS has a corresponding MUB. We show that this no longer holds for certain composite dimensions.Comment: 6 pages, submitted to Proceedings of CEWQO 200

Differential gene transfers and gene duplications in primary and secondary endosymbioses

BACKGROUND: Most genes introduced into phototrophic eukaryotes during the process of endosymbiosis are either lost or relocated into the host nuclear genome. In contrast, groEL homologues are found in different genome compartments among phototrophic eukaryotes. Comparative sequence analyses of recently available genome data, have allowed us to reconstruct the evolutionary history of these genes and propose a hypothesis that explains the unusual genome distribution of groEL homologues. RESULTS: Our analyses indicate that while two distinct groEL genes were introduced into eukaryotes by a progenitor of plastids, these particular homologues have not been maintained in all evolutionary lineages. This is of significant interest, because two chaperone proteins always co-occur in oxygenic photosynthetic organisms. We infer strikingly different lineage specific processes of evolution involving deletion, duplication and targeting of groEL proteins. CONCLUSION: The requirement of two groEL homologues for chaperon function in phototrophs has provided a constraint that has shaped convergent evolutionary scenarios in divergent evolutionary lineages. GroEL provides a general evolutionary model for studying gene transfers and convergent evolutionary processes among eukaryotic lineages