Do we (still) need to regulate fixed network retail markets?

In the beginning of fixed network liberalisation in Europe in the late 1990s, the main concern of regulators was to lower calls prices. This was done by introducing wholesale regulation and promoting service based competition. Some years later, the concern of some regulators turned from too high calls prices to too low calls prices which might ‘squeeze’ entrants out of the market. We look at a simple model in which this development is explained by increasing competitive pressure from an ‘outside opportunity’, e.g. mobile telephony. We conclude that a margin squeeze is not necessarily used by the incumbent as a device to drive competitors out of the market and increase market power but can also result from increased inter-model competition. If this is the case, we argue that regulators should consider alternatives to cost oriented access prices such as retail minus or complete deregulation.access regulation, vertical integration, foreclosure, price squeeze, telecommunications, fixed networks

Margin Squeeze in Fixed-Network Telephony Markets – competitive or anticompetitive?

This paper looks at the effects of different forms of wholesale and retail regulation on retail competition in fixed network telephony markets. We explicitly model two asymmetries between the incumbent operator and the entrant: (i) While the incumbent has zero marginal costs, the entrant has the wholesale access charge as (positive) marginal costs; (ii) While the incumbent is setting a two-part tariff at the retail level (fixed fee and calls price), the entrant can only set a linear price for calls. Competition from other infrastructures such as mobile telephony or cable is modelled as an ‘outside opportunity’ for consumers. We find that a horizontally differentiated entrant with market power may be subject to a margin squeeze due to double marginalization but will never be completely foreclosed. Entrants without market power might be subject to a margin squeeze if the wholesale access price is set at average costs and competitive pressure from other infrastructures increases. We argue that a wholesale price regulation at average costs is not optimal in such a situation and discuss retail minus and deregulation as potential alternatives.access regulation, foreclosure, margin squeeze, telecommunications, fixed networks

Die Konstitution der Silicatanionen im kristallinen 2PbO - SiO2. - II.

Die Konstitution der Silicatanionen in den kristallinen Modifikationen TPb2SiO4, M2Pb2SiO4 und HPb2SiO4 wurde untersucht. Es ergab sich, daß TPb2SiO4 vorwiegend Silicatanionen des Typs [Si2O7]6- neben [Si3O10]8- und [SiO4]4- enthält; HPb2SiO4 besteht aus Polysilicatanionen, und M2Pb2SiO4 bildet einen Übergang zwischen dem aus Cyclotetrasilicatanionen [Si4O12]8- aufgebauten M1Pb2SiO4 und HPb2SiO4. Die Anionengruppen im T-, M1- und M2Pb2SiO4 sind thermisch instabil und bedingen die Modifikationsumwandlungen, wodurch sich bei geeigneter thermischer Behandlung durch die Polymerisation der Silicatanionen das stabile H-Pb2SiO4 mit Polysilicatanionen bildet.HPb2SiO4 is a polysilicate and M2Pb2SiO4 is an intermediate between M1Pb2SiO4. which contains tetrameric ring anions [Si4O12]8- and HPb2SiO4. The anionic groups in T-, M1-, and M2- Pb2SiO4 are thermally instable and this is the reason for the metastability of these modifications, which change into the polysilicate HPb2SiO4 by polymerization of silicate anions

Die Konstitution der Silicatanionen im kristallinen 2PbO . SiO2. - I.

Aus einem Glas der Zusammensetzung 2 PbO·SiO2 wurde durch 24ständiges Tempern bei 500°C ein kristallines Bleisilicat hergestellt, welches nach röntgenographischen und IR-Absorptionsmessungen mit dem von Billhardt beschriebenem M1-Pb2SiO4 identisch ist. Untersuchungen zur Konstitution der Silicatanionen in dieser Substanz, die mit Hilfe der Papierchromatographie und der Molybdatmethode durchgeführt wurden, ergaben, daß im kristallinen Bleisilicat Cyclotetrasilicatanionen [Si4O12]8- vorliegen

The secondary work embrittlement in sheet steels

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135493/1/srin05619.pd

Parameter estimation from occupation times—a white noise approach

We derive an equation to compute directly the expected occupation time of the centered Ornstein–Uhlenbeck process. This allows us toidentify the parameters of the Ornstein–Uhlenbeck process for available occupation times via a standard least squares minimization. To test the method,we generate occupation times via Monte–Carlo simulations and recover theparameters with the above mentioned procedure

Bioactive coatings of glass-ceramics on metals

To combine the mechanical properties of high-strength base metals with the biological properties of bioactive materials, coatings of BIOVERIT® glasses and glass-ceramics on CoCr alloys and titanium have been produced. Different kinds of coating processes have been used: dipping, sputtering, plasma spraying, sintering and pasting. Dipping and pasting seem not to be suitable to produce layers because of cracks and low adhesion strength of the coatings (dipping) and the limitations in relation to the implant shape and the thickness of the layers (pasting). Using sputter techniques it is possible to produce dense layers ( < 10µim) with a high adhesion strength. Plasma spraying resuhed in layers with a thickness of 50 to 300µim, but during the plasma spraying process there is a partial evaporation of the highly volatile glass components. Sintering processes are very suitable to produce layers with a high adhesion strength; these layers are long term stable in simulated body fluid

Die Konstitution der Silicatanionen im kristallinen 2PbO . SiO2. - I.

Aus einem Glas der Zusammensetzung 2 PbO·SiO2 wurde durch 24ständiges Tempern bei 500°C ein kristallines Bleisilicat hergestellt, welches nach röntgenographischen und IR-Absorptionsmessungen mit dem von Billhardt beschriebenem M1-Pb2SiO4 identisch ist. Untersuchungen zur Konstitution der Silicatanionen in dieser Substanz, die mit Hilfe der Papierchromatographie und der Molybdatmethode durchgeführt wurden, ergaben, daß im kristallinen Bleisilicat Cyclotetrasilicatanionen [Si4O12]8- vorliegen