Sealed Bid Auctions vs. Ascending Bid Auctions: An Experimental Study

This paper considers the sealed bid and ascending auction, which both identifies the minimum Walrasian equilibrium prices and where truthful preference revelation constitutes an equilibrium. Even though these auction formats share many theortical properties, there are behavioral aspects that are not easily captured. To explore this issue in more detail, this paper experimentally investigates what role the design of the auction format has for its outcome. The results suggest that the sealed bid mechanism performs weakly better in all of investigated measures (consistent reporting, efficiency etc.). In addition, we find that the performance of the ascending auction is increasing over time, whereas the sealed bid auction shows no such tendency.Auctions; Non-manipulability; Efficiency; Experiments

Costly Renegotiation in Repeated Bertrand Games

This paper extends the concept of weak renegotiation-proof equilibrium (WRP) to allow for costly renegotiation and shows that even small renegotiation costs can have dramatic effects on the set of equilibria. More specifically, the paper analyzes the infinitely repeated Bertrand game. It is shown that for every level of renegotiation cost there exists a discount factor such that any collusive profit can be supported as an equilibrium outcome. Hence, any arbitrary small renegotiation cost will suffice to facilitate collusive outcomes for sufficiently patient firms. This result stands in stark contrast to the unique pure-strategy WRP equilibrium without renegotiation costs, which implies marginal-cost pricing in every period. Moreover, in comparison to the findings of McCutcheon (1997), who states that renegotiation costs have to be substantial to facilitate collusion, this result points to a quite different conclusion.Noncooperative game theory; Weak Renegotiation-proofness; Costly Renegotation; Repeated Bertrand games

Credible Communication and Cooperation: Experimental Evidence from Multi-stage Games

It is well known that communication often serves as a facilitator for cooperation in static games. Yet, communication can serve entirely different purposes in dynamic settings as communication during the game may work as a means for renegotiation, potentially undermining the credibility of cooperative strategies. To explore this issue, this paper experimentally investigates cooperation and non-binding communication in a two-stage game. More specifically, two treatments are considered: one with only pre-play communication and one where subjects can also communicate intra-play between the stages of the game. The results highlight a nontrivial difference concerning the effects of pre-play communication between the two treatments. Pre-play communication only has a significant impact on cooperation when no intra-play communication is possible. The results suggest that the credibility of pre-play messages may depend crucially on future communication opportunities.Communication; Cooperation; Renegotiation; Experiments

Robustness to strategic uncertainty in price competition

We model a player's uncertainty about other player's strategy choices as probability distributions over their strategy sets. We call a strategy profile robust to strategic uncertainty if it is the limit, as uncertainty vanishes, of some sequence of strategy profiles in each of which every player's strategy is optimal under his or her uncertainty about the pthers. We apply this definition to Bertrand games with a continuum of equilibrium prices and show that our robustness criterion selects a unique Nash equilibrium price. This selection agrees with available experimental findings.Nash equilibrium; refinement; strategic uncertainty; price competition

Structural Change, Competition and Job Turnover in the Swedish Manufacturing Industry 1964-96

The rate of inter-industry job turnover in Swedish manufacturing seems to be driven by the dispersion of profit changes among industries. Shifts in international competitiveness among industries played a central role for explaining this pattern. The rate of intra-industry job turnover among plants has been higher in industries with many small plants, low profit margins and high import penetration.Comparative advantage; market power; structural change; job turnover

Effect of delayed versus early umbilical cord clamping on neonatal outcomes and iron status at 4 months: a randomised controlled trial

Objective To investigate the effects of delayed umbilical cord clamping, compared with early clamping, on infant iron status at 4 months of age in a European setting

Using design-of-experiments techniques for an efficient finite element study of the influence of changed parameters in design

All designs are marred by uncertainties and tolerances in dimen- sions, load levels etc. Traditionally, one has often over-dimensioned to take these uncertainties into account. The demand for optimized designs with high quality and reliability increases, which means that more sophisticated methods have been developed, see e.g. Lochner and Matar (1990). By describing the fluctuations in design parame- ters in terms of distributions with expectation and variance, the design can be examined with statistical methods, which results in a more op-timized design. This treatment of the design often demands several experiments, and to plan these experiments Design Of Experiments (DOE) techniques, see e.g. Montgomery (1991), are often used. By using DOE methods the design variables are systematically altered, which minimizes the number of experiments needed. The output of the experiments is the results of a specified response function, giving an indication of the influence of design variable fluctuations. A FEM system is a suitable tool when performing repeated, similar analyses. Examples exist where the DOE process has been performed external- ly and then transferred to the FEM system in the form of parameter sets defining the analysis cases that are to be solved, see e.g. Summers et al. (1996) and Billings (1996). This paper describes a statistical DOE module based on Taguchi’s method that works within ANSYS. The module plans the FEM anal-ysis and calculates the standard statistical moments of the FEM result. This module serves as a powerful tool for the engineering designer or analysts when examining the influence of variance and mean value of different design variables. It also serves as an exploration of where to concentrate an optimization process

STRUCTURAL CHANGE, COMPETITION AND JOB TURNOVER IN THE SWEDISH MANUFACTURING INDUSTRY 1964-96

The rate of inter-industry job turnover in Swedish manufacturing seems to be driven by the dispersion of profit changes among industries. Shifts in international competitiveness among industries played a central role for explaining this pattern. The rate of intra-industry job turnover among plants has been higher in industries with many small plants, low profit margins and high import penetration.comparative advantage; market power; structural change; job turnover

Human papillomavirus subtypes are not uncommon

AbstractWhile both variants and types of human papillomavirus (HPV) are common, subtypes (2–10% sequence divergence in the L1 gene) have been considered to be rare. We searched GenBank and in-house databases using a 440 nt L1 fragment and identified 7, 30 and 10 subtypes/putative subtypes in the HPV genera Alpha, Beta and Gamma, respectively. The number of types/putative types in each genus was 54, 58 and 103. Thus, there appears to exist at least 47 different subtypes/putative subtypes of HPV and they seem to be particularly common in the genus Beta-papillomavirus

Pseudovirion-binding and neutralizing antibodies to cutaneous Human Papillomaviruses correlated to presence of HPV DNA in skin.

We compared seroreactivity to Human papillomavirus (HPV) antigens measured with two different high-throughput assays. One method used GST-L1 fusion proteins and the other heparin-bound HPV pseudovirions as antigens and both methods used multiplexed fluorescent beads for detection. For six HPV types (5, 6, 15, 16, 32 and 38), seroreactivity could be measured in parallel for 434 serum samples from non-immunosuppressed patients with skin lesions (squamous cell carcinoma of the skin, basal cell carcinoma of the skin, actinic keratosis and benign skin lesions). Biopsies from the skin lesions were tested for presence of HPV DNA using three different PCR methods, with typing by sequencing. Among the types included in the serological tests, HPV DNA of types HPV5, 15, 38 and 76 were most frequently detected in the tumours. Serum samples from subjects with HPV DNA positive biopsies and randomly selected serum samples from subjects with HPV DNA negative biopsies were also tested with neutralization assays with HPV5, 38 and 76 pseudovirions. Agreement of the three serological methods varied from poor to moderate and showed limited consistency. Type-specific seroprevalences among patients positive for the same type of HPV DNA (sensitivity of serology) was improved with the pseudovirion-based method (average of 40%, maximum 63%) compared to the GST-L1 method (average of 20%, maximum of 25%). Neutralization was the most sensitive assay for HPV38 (50%). In summary, the pseudovirion-based methods appeared to have an improved sensitivity