Tradition, modernity and the future of African theology

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Auction Fever: Theory and Experimental Evidence

It is not a secret that certain auction formats yield on average higher prices than others. The phenomenon that dynamic auctions are more likely to elicit higher bids than static one-shot auctions is often associated with the term ''auction fever.'' On a psychological level, we consider the so-called pseudo-endowment effect as largely responsible for peoples’ tendency to submit higher bids, potentially amplified by the source-dependence effect. The phenomenon of auction fever is replicated in an experimental investigation of different auction formats within a private values framework where bidders have private but incomplete knowledge of their valuation for a hypothetical good. We suggest this assumption to be more realistic than definite private values, as assumed in the traditional IPV model. An additional experimental investigation within the traditional IPV framework does not either reveal any indication for the appearance of auction fever. On the basis of our experimental observations we present a model of reference-dependent utility theory that comprehends the phenomenon by assuming that bidders' reference points are shifted by the pseudo-endowment and the source-dependence effect.

Myopically Forward-Looking Agents in a Network Formation Game: Theory and Experimental Evidence

A population of players is considered in which each agent can select her neighbors in order to play a 2x2 Hawk-Dove game with each of them. We design our experiment in continuous time where participants may change their Hawk-Dove action and/or their neighborhood at any point in time. We are interested in the resulting formation of networks and the action distributions. Compared with static Nash equilibrium (e.g., Berninghaus and Vogt, 2004, 2006; Bramoulle, Lopez-Pintado, Goyal, and Vega-Redondo, 2004) and social optimum as theoretical benchmark solutions, subjects seem to employ a more complex, forward-looking thinking. We develop an other benchmark solution, called one-step-ahead stability, that combines forward-looking belief formation with rational response and that fits the data much better.

Effective strategies for enumeration games

We study the existence of effective winning strategies in certain infinite games, so called enumeration games. Originally, these were introduced by Lachlan (1970) in his study of the lattice of recursively enumerable sets. We argue that they provide a general and interesting framework for computable games and may also be well suited for modelling reactive systems. Our results are obtained by reductions of enumeration games to regular games. For the latter effective winning strategies exist by a classical result of Buechi and Landweber. This provides more perspicuous proofs for several of Lachlan\u27s results as well as a key for new results. It also shows a way of how strategies for regular games can be scaled up such that they apply to much more general games

Auctions, information, and new technologies

Auctions have been developed for economic transactions with asymmetric information and they are the simplest means of price determination for multilateral trading without "market makers." During the last years, new technologies gave a boost to the development and usage of innovative auction formats in several fields. We explore some of the new possibilities of applications and explain the differences to traditional auction formats. Furthermore, we demonstrate the potentialities of auctions concerning information gaining for the auctioneer as well as for the participating bidders

Auctions, information, and new technologies

Auctions have been developed for economic transactions with asymmetric information and they are the simplest means of price determination for multilateral trading without "market makers." During the last years, new technologies gave a boost to the development and usage of innovative auction formats in several fields. We explore some of the new possibilities of applications and explain the differences to traditional auction formats. Furthermore, we demonstrate the potentialities of auctions concerning information gaining for the auctioneer as well as for the participating bidders

Green Arrow vs. Hawkeye

It was during the twentieth annual Secre

How the auction design influences procurement prices: an experiment

The targeted design of auctions has to take behavioral regularities into account. This paper explores whether procurement auction formats can take advantage of bidders' willingness-to-pay-willingness-to-accept disparity. In a laboratory experiment, we compare four different second-price auction formats for procuring a good. The four formats are a sealed-bid auction and three different descending-clock auctions. We assume that a bidder's willingness-to-accept exceeds his willingness-to-pay and that, depending on the auction format, a bidder's reference-state shifts such that the bidder's perspective moves from a willingness-to-accept perspective towards a willingness-to-pay perspective, thus inducing aggressive bids. In line with the prediction, auction prices decline across the four formats. In particular, we observe the lowest prices in those two clock auction formats that, at every auction stage, select a bidder as the current leading bidder. We conclude that mechanisms influence the reference state and that auctions that foster reference-state shifts lead to lower payments for the buyer. These results support and generalize findings on sales auctions. However, not all of our findings on procurement auctions mirror findings on sales auctions. Bidders overbid in sealed-bid procurement auctions, which does not mirror the commonly observed overbidding in sealed-bid sales auctions

Correcting ligands, metabolites, and pathways

BACKGROUND: A wide range of research areas in bioinformatics, molecular biology and medicinal chemistry require precise chemical structure information about molecules and reactions, e.g. drug design, ligand docking, metabolic network reconstruction, and systems biology. Most available databases, however, treat chemical structures more as illustrations than as a datafield in its own right. Lack of chemical accuracy impedes progress in the areas mentioned above. We present a database of metabolites called BioMeta that augments the existing pathway databases by explicitly assessing the validity, correctness, and completeness of chemical structure and reaction information. DESCRIPTION: The main bulk of the data in BioMeta were obtained from the KEGG Ligand database. We developed a tool for chemical structure validation which assesses the chemical validity and stereochemical completeness of a molecule description. The validation tool was used to examine the compounds in BioMeta, showing that a relatively small number of compounds had an incorrect constitution (connectivity only, not considering stereochemistry) and that a considerable number (about one third) had incomplete or even incorrect stereochemistry. We made a large effort to correct the errors and to complete the structural descriptions. A total of 1468 structures were corrected and/or completed. We also established the reaction balance of the reactions in BioMeta and corrected 55% of the unbalanced (stoichiometrically incorrect) reactions in an automatic procedure. The BioMeta database was implemented in PostgreSQL and provided with a web-based interface. CONCLUSION: We demonstrate that the validation of metabolite structures and reactions is a feasible and worthwhile undertaking, and that the validation results can be used to trigger corrections and improvements to BioMeta, our metabolite database. BioMeta provides some tools for rational drug design, reaction searches, and visualization. It is freely available at provided that the copyright notice of all original data is cited. The database will be useful for querying and browsing biochemical pathways, and to obtain reference information for identifying compounds. However, these applications require that the underlying data be correct, and that is the focus of BioMeta

Evolution of YidC/Oxa1/Alb3 insertases: three independent gene duplications followed by functional specialization in bacteria, mitochondria and chloroplasts

Members of the YidC/Oxa1/Alb3 protein family facilitate the insertion, folding and assembly of proteins of the inner membranes of bacteria and mitochondria and the thylakoid membrane of plastids. All homologs share a conserved hydrophobic core region comprising five transmembrane domains. On the basis of phylogenetic analyses, six subgroups of the family can be distinguished which presumably arose from three independent gene duplications followed by functional specialization. During evolution of bacteria, mitochondria and chloroplasts, subgroup-specific regions were added to the core domain to facilitate the association with ribosomes or other components contributing to the substrate spectrum of YidC/Oxa1/Alb3 proteins