Revenue Equivalence Revisited

The conventional wisdom in the auction design literature is that first price sealed bid auctions tend to make more money while ascending auctions tend to be more efficient. We re-examine these issues in an environment in which bidders are allowed to endogenously choose in which auction format to participate. Our findings are that more bidders choose to enter the ascending auction than the first price sealed bid auction and this extra entry is enough to make up the revenue difference between the formats. Consequently, we find that both formats raise approximately the same amount of revenue. They also generate efficiency levels and bidder earnings that are roughly equivalent across mechanisms though the earnings in the ascending might be slightly higher. In expected utility terms though, we find that the expected utility of entering a first price sealed bid auction is greater than entering an ascending for any risk averse bidder suggesting that we are seeing “overentry” into the ascending auctions

Anomalies in Auction Choice Behavior

Ivanova-Stenzel and Salmon (2004a) established some interesting yet puzzling results regarding bidders’ preferences between auction formats. The finding is that bidders strongly prefer the ascending to the first price sealed bid auction on a ceteris paribus basis but they are not willing to pay up to an entry price for entering into an ascending auction instead of a first price that would equalize the profits between the two. While it was found that risk aversion on the part of the bidders could resolve this anomaly the claim that risk aversion drives overbidding in first price auctions is somewhat controversial. In this study we examine two competing explanations for the observed behavior; loss aversion and “clock aversion”, i.e. a dislike for some aspect of the clock based bidding mechanism. We find that neither alternative explanation can account for bidders’ auction choice behavior leaving risk aversion as the only un-falsified hypothesis

Revenue Equivalence Revisited

The conventional wisdom in the auction design literature is that first price sealed bid auctions tend to make more money while ascending auctions tend to be more efficient. We re-examine these issues in an environment in which bidders are allowed to endogenously choose in which auction format to participate. Our findings are that more bidders choose to enter the ascending auction than the first price sealed bid auction and this extra entry is enough to make up the revenue difference between the formats. Consequently, we find that both formats raise approximately the same amount of revenue. They also generate efficiency levels and bidder earnings that are roughly equivalent across mechanisms though the earnings in the ascending might be slightly higher. In expected utility terms though, we find that the expected utility of entering a first price sealed bid auction is greater than entering an ascending for any risk averse bidder suggesting that we are seeing “overentry†into the ascending auctions.bidder preferences; private values; sealed bid auctions; ascending auctions; endogenous entry

Bidder Preferences Among Auction Institutions

This study examines bidder preferences between alternative auction institutions. We seek to experimentally characterize the degree to which bidders prefer an ascending auction to a sealed bid auction. We find very strong ceteris paribus preferences for the ascending institution with bidders choosing it overwhelmingly often when entry prices for the two auctions are the same. When the entry prices of the two auctions differ, many subjects can be shown to be willing to pay more to enter the ascending auction than is explainable by their risk attitudes when accounting for their expectations about the risk preferences of their opponents.auctions, mechanism design, electronic markets

Quantum phases and topological properties of interacting fermions in one-dimensional superlattices

The realization of artificial gauge fields in ultracold atomic gases has opened up a path towards experimental studies of topological insulators and, as an ultimate goal, topological quantum matter in many-body systems. As an alternative to the direct implementation of two-dimensional lattice Hamiltonians that host the quantum Hall effect and its variants, topological charge-pumping experiments provide an additional avenue towards studying many-body systems. Here, we consider an interacting two-component gas of fermions realizing a family of one-dimensional superlattice Hamiltonians with onsite interactions and a unit cell of three sites, whose groundstates would be visited in an appropriately defined charge pump. First, we investigate the grandcanonical quantum phase diagram of individual Hamiltonians, focusing on insulating phases. For a certain commensurate filling, there is a sequence of phase transitions from a band insulator to other insulating phases (related to the physics of ionic Hubbard models) for some members of the manifold of Hamiltonians. Second, we compute the Chern numbers for the whole manifold in a many-body formulation and show that, related to the aforementioned quantum phase transitions, a topological transition results in a change of the value and sign of the Chern number. We provide both an intuitive and conceptual explanation and argue that these properties could be observed in quantum-gas experiments

Semantics-directed implementation of method-call interception

We describe a form of method-call interception (MCI) that allows the programmer to superimpose extra functionality onto method calls at run-time. We provide a reference semantics and a reference implementation for corresponding language constructs. The setup applies to class-based, statically typed, compiled languages such as Java. The semantics of MCI is used to direct a language implementation with a number of valuable properties: simplicity of the implementational model and run-time adaptation capabilities and static type safety and separate compilation and reasonable performance. Our implementational development employs sourcecode instrumentation. We start from a naive implementational model, which is subsequently refined to optimise program execution. The implementation is assessed via benchmarks

The High/Low Divide: Self- Selection by Values in Auction Choice

Most prior theoretical and experimental work involving auction choice has assumed bidders only find out their value after making a choice of which autcion to enter. In this paper we examine whether or not subjects knowing their value prior to making an auction choice impacts their choice decision and/or the outcome of the auctions. The results show a strong impact. Subjects with low values choose the first price sealed bid auction more often while subjects with high values choose the ascending auction more often. The average numbers of bidders in both formats ended up being on average the same, but due to the self-selection bias the ascending auction raised as much revenue on average as the first sealed bid auction. The two formats also generate efficiency levels that are roughly equivalent though the earnings of bidders are higher in the ascending auction

Basic Considerations on the Overlap Detectors of the ATLAS ALFA system

We discuss the motivation and possible implementation of Overlap Detectors for the relative alignment of the two halves of the ATLAS Roman Pot detectors. We propose a system design and a set of prototype detectors for a proof of principle in a test beam experiment

IL-1α and TNF-α Down-Regulate CRH Receptor-2 mRNA Expression in the Mouse Heart

Two receptors (CRH receptor type 1 and CRH receptor type 2) have been identified for the stress-induced neuropeptide, CRH and related peptides, urocortin, and urocortin II. We previously found marked down-regulation of cardiac CRH receptor type 2 expression following administration of bacterial endotoxin, lipopolysaccharide, a model of systemic immune activation, and inflammation. We postulated that inflammatory cytokines may regulate CRH receptor type 2. We show that systemic IL-1α administration significantly down-regulates CRH receptor type 2 mRNA in mouse heart. In addition, TNFα treatment also reduces CRH receptor type 2 mRNA expression, although the effect was not as marked as with IL-1α. However, CRH receptor type 2 mRNA expression is not altered in adult mouse ventricular cardiomyocytes stimulated in vitro with TNFα or IL-1α. Thus, cytokine regulation may be indirect. Exogenous administration of corticosterone in vivo or acute restraint stress also reduces cardiac CRH receptor type 2 mRNA expression, but like cytokines, in vitro corticosterone treatment does not modulate expression in cardiomyocytes. Interestingly, treatment with urocortin significantly decreases CRH receptor type 2 mRNA in cultured cardiomyocytes. We speculate that in vivo, inflammatory mediators such as lipopolysaccharide and/or cytokines may increase urocortin, which in turn down-regulates CRH receptor type 2 expression in the heart. Because CRH and urocortin increase cardiac contractility and coronary blood flow, impaired CRH receptor type 2 function during systemic inflammation may ultimately diminish the adaptive cardiac response to adverse conditions