Introduction: Theory and Application of Electronic Market Design

Markets play a central role in the economy, facilitating the exchange of information, goods, services, and payments. Recent years have seen an enormous increase in the role of information technology in markets, in particular the emergence of electronic marketplaces. Different matching mechanisms are appropriate in different situations and there is not a single solution that caters for all the various negotiation situations. Therefore, economists, game theorists, and computer scientists have started to take a direct role by designing various kinds of negotiation mechanisms for computer products, travel, insurance, and utilities such as power and gas. What is so special about electronic market design is the fact that a designer has many more possibilities to design a negotiation mechanism than one would have for physical markets. The design of electronic markets involves a number of disciplines including game theory, mechanism design theory, simulation and laboratory experimentation. The focus of this special issue is to provide an overview of several new approaches in the field, and we are pleased to bring you an exciting selection of high standing papers. This article is intended to provide a brief introduction to this new and dynamic field.     

The problem of Caesarean section (author's transl)

The Caesarean sections at the Universit?ts-Frauenklinik Innsbruck from January 1st, 1969 to December 31st, 1974 have been surveyed. Related to the total number of 12 579 deliveries 627 Caesarean sections have been performed. Two 3-year-intervals have been compared: 1969-1971 (group I) without and 1972-1974 (group II) with modern practices of prenatal supervision. There was a high significant increase of the section rate in group II (5,8% versus 4,1% which has been related to the increasing number of mainly fetal indications. The maternal morbidity didn't rise with the increasing section rate. A significant decrease in total infant mortality rate and mortality rate at vaginal deliveries has been found with the increasing incidence of Caesarean sections; whereas the number of depressed infants (Apgar score less than 7) was increased in group II. The reasons therefore have been discussed. The rise of the number of Caesarean sections in group II performed because of breech presentation (14,2% versus 6,2%) was correspondent with a statistically significant decrease in the mortality rate from 11,7 to 4,1%. A Caesarean section rate between 7% and 10% seems to be the limit at least in our hospital--the total infant mortality rate cannot be reduced by further increasing the section frequency: the infant mortality rate possibly could be lowered by a better and more wide spread prenatal care especially by taking more care for prematurity and by intensifying the perinatal period.     

A non-parametric estimator for setting reservation prices in procurement auctions

Electronic auction markets collect large amounts of auction field data. This enables a structural estimation of the bid distributions and the possibility to derive optimal reservation prices. In this paper we propose a new approach to setting reservation prices. In contrast to traditional auction theory we use the buyer’s risk statement for getting a winning bid as a key criterion to set an optimal reservation price. The reservation price for a given probability can then be derived from the distribution function of the observed drop-out bids. In order to get an accurate model of this function, we propose a nonparametric technique based on kernel distribution function estimators and the use of order statistics. We improve our estimator by additional information, which can be observed about bidders and qualitative differences of goods in past auctions rounds (e.g. different delivery times). This makes the technique applicable to RFQs and multi-attribute auctions, with qualitatively differentiated offers.     

Electrical control of the exciton-biexciton splitting in self-assembled InGaAs quantum dots

The authors demonstrate how lateral electric fields can be used to precisely control the exciton-biexciton splitting in InGaAs quantum dots. By defining split-gate electrodes on the sample surface, optical studies show how the exciton transition can be tuned into resonance with the biexciton by exploiting the characteristically dissimilar DC Stark shifts. The results are compared to model calculations of the relative energies of the exciton and biexciton, demonstrating that the tuning can be traced to a dominance of hole-hole repulsion in the presence of a lateral field. Cascaded decay of the exciton-biexciton system enables the generation of entangled photon pairs without the need to suppress the fine structure splitting of the exciton. Our results demonstrate how the exciton-biexciton system can be electrically controlled.     

Evolution of Strain and Microstructure During Creep of Wrought AE42 and ZE10 Magnesium Alloys

Wrought magnesium alloys have been extensively used in the aerospace, electronics and automotive industries, where component weight is of concern and ambient temperatures remain below 100 °C. Undesirable creep relaxation of the wrought alloys above this temperature has been generally attributed to grain boundary sliding and plastic deformation leading to intergranular failure. The objective of this study was to investigate the compressive creep performance and microstructure of two wrought magnesium alloys (AE42 and ZE10) developed for high temperature applications. The total deformation of the AE42 and ZE10 alloys was 2.4 and 0.2 %, respectively, after 24 h creep test at 175 °C and 50 MPa. The poor creep performance of the AE42 alloy was explained via neutron diffraction studies which revealed that the elastic compressive response of $ (10\bar{1}0),\;(10\bar{1}1)\;{\text{and}}\;(2\bar{1}\bar{1}0) $ planes was significantly more anisotropic in the AE42 than in the ZE10 alloy. Further, microstructural analysis revealed ~10 % increase in grain size due to creep, with additional $ (10\bar{1}2) $ and $ (11\bar{2}1) $ twinning in the AE42 alloy. Precipitation of β-Mg₁₇Al₁₂ phase in the AE42 alloy possibly contributed to grain boundary sliding and high plastic strain during creep testing.     

Degeneration of cochlear neurons after amikacin intoxication in the rat

Intoxication with high doses of the aminoglycoside antibiotic amikacin in a supranormal sensitive period in the rat induces complete destruction of the inner and outer hair cells in the organ of Corti in all turns, whereas the supporting cells remain partially preserved in the upper turns. With increasing survival time, the number of ganglion cells in the spiral ganglion decreases progressively, reaching a minimum of about 10% surviving cells after 12 months. Both type I and type II neurons are subject to retrograde degeneration, although type-II cells degenerate more slowly than type-I cells. The presence or absence of supporting cells in the organ of Corti does not seem to influence neuronal degeneration. This retrograde degeneration is similar in all animals so far studied but its time course is different from different species. Retrograde degeneration after destruction of Corti's organ is a long-lasting process and is never completed at once. This must be taken into consideration in the treatment of total deafness with electric stimulation of surviving neurons.     

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