Bertrand competition with intertemporal demand

In the text-book model of dynamic Bertrand competition, competing firms meet the same demand function every period. This is not a satisfactory model of the demand side if consumers can make intertemporal substitution between periods. Each period then leaves some residual demand to future periods, and consumers who observe price under-cutting may correctly anticipate an ensuing price war and therefore postpone their purchases. Accordingly, the interaction between the firms no longer constitutes a repeated game, and hence falls outside the domain of the usual Folk theorems. We analyze collusive pricing in such situations, and study cases when consumers have perfect and imperfect foresight and varying degrees of patience. It turns out that collusion against patient and forward-looking consumers is easier to sustain than collusion in the text-book model

Shrouding add-on information: an experimental study

We explore how increased competition affects firms’ obfuscation strategies in a laboratory experiment. Firms sell a base good and an add‐on product. Besides choosing the base‐good price, sellers take an action that mimicks the effects of shrouding the add‐on product. Shrouding is an equilibrium, but an unshrouding equilibrium coexists. In our experiment, more competition matters in that only duopolistic markets are frequently shrouded whereas four‐firm markets are not. With repeated interaction, shrouding rates do not increase. However, the opportunities to shroud facilitate tacit collusion on the base‐good price for the duopolies: the unshrouding equilibrium serves as a credible punishment if deviations occur

A design theory for e-service environments: The interoperability challenge

The delivery of e-services across organizational boundaries poses a number of issues in terms of design of inter-organizational systems that support service delivery effectively. In this context interoperability emerges as a mandatory requirement for the design of Information Technology (IT) platforms supporting collaborative e-service environments. In this paper we address this issue by presenting a design theory for IT platforms supporting e-services based on both a deep understanding of the interoperability concept and a design research approach. Through the analysis of a cooperation framework developed in the context of an EU funded project, we instantiate the theory by providing the concrete example of a solution addressing this design problem. © 2012 Springer-Verlag GmbH Berlin Heidelberg.The delivery of e-services across organizational boundaries poses a number of issues in terms of design of inter-organizational systems that support service delivery effectively. In this context interoperability emerges as a mandatory requirement for the design of Information Technology (IT) platforms supporting collaborative e-service environments. In this paper we address this issue by presenting a design theory for IT platforms supporting e-services based on both a deep understanding of the interoperability concept and a design research approach. Through the analysis of a cooperation framework developed in the context of an EU funded project, we instantiate the theory by providing the concrete example of a solution addressing this design problem. © 2012 Springer-Verlag GmbH Berlin Heidelberg.Monograph's chapter

Adaptive response and enlargement of dynamic range

Many membrane channels and receptors exhibit adaptive, or desensitized, response to a strong sustained input stimulus, often supported by protein activity-dependent inactivation. Adaptive response is thought to be related to various cellular functions such as homeostasis and enlargement of dynamic range by background compensation. Here we study the quantitative relation between adaptive response and background compensation within a modeling framework. We show that any particular type of adaptive response is neither sufficient nor necessary for adaptive enlargement of dynamic range. In particular a precise adaptive response, where system activity is maintained at a constant level at steady state, does not ensure a large dynamic range neither in input signal nor in system output. A general mechanism for input dynamic range enlargement can come about from the activity-dependent modulation of protein responsiveness by multiple biochemical modification, regardless of the type of adaptive response it induces. Therefore hierarchical biochemical processes such as methylation and phosphorylation are natural candidates to induce this property in signaling systems.Comment: Corrected typos, minor text revision

Energy loss of proton and lead beams in the CERN-SPS

The energy loss of an unbunched beam circulating in the CERN-SPS has been obtained from the observed frequency change of a longitudinal Schottky signal. This experiment was carried out for protons at 14, 120 and 270 GeV/c and for lead ions PB82208 at Z .270 GeV/c momentum. The dominant effects which determine the energy loss are synchrotron radiation, ionization of the residual gas and parasitic mode loss in the resistive longitudinal impedance. Since all the protons in a lead nucleus radiate coherently the synchrotron radiation is proportional to Z2 like the other effects. The experimental results are analyzed and the contributions of the individual effects determined. Using an impedance of | Z/n | ~ 12 W gives the best fit through the experimental data

The SPS as lead-ion accelerator

In 1995 the CERN SPS was used during two months to accelerate fully stripped ions of the Pb208 isotope from the equivalent proton momentum of 13 GeV/c to 400 GeV/c. The radio frequency swing which is needed in order to keep the synchronism during acceleration is too big to have the SPS cavities deliver enough voltage for all frequencies. In a first stage, the beam is accelerated from 13 GeV/c to 26 GeV/c using the fixed frequency mode. During this stage the beam is grouped in four 2msec batches, separated by 3msec holes during which the frequency is changed in order to keep synchronism. At 26 GeV the beams are de-bunched and recaptured in order to fill the 3msec holes. From there on the lead ions are then accelerated up to 400 GeV/c with the normal frequency program. The de-bunching and recapture at 26 GeV improved the effective spill at extraction by a factor of three. Intensities up to 3.9 1010 charges could be obtained at 400 GeV/c. The total efficiency of the two RF captures was 64%

Fusion of secretory vesicles isolated from rat liver

Secretory vesicles isolated from rat liver were found to fuse after exposure to Ca2+. Vescle fusion is characterized by the occurrence of twinned vesicles with a continuous cleavage plane between two vesicles in freeze-fracture electron microscopy. The number of fused vesicles increases with increasing Ca2+-concentrations and is half maximal around 10–6 m. Other divalent cations (Ba2+, Sr2+, and Mg2+) were ineffective. Mg2+ inhibits Ca2+-induced fusion. Therefore, the fusion of secretory vesiclesin vitro is Ca2+ specific and exhibits properties similar to the exocytotic process of various secretory cells. Various substances affecting secretionin vivo (microtubular inhibitors, local anethetics, ionophores) were tested for their effect on membrane fusion in our system. The fusion of isolated secretory vesicles from liver was found to differ from that of pure phospholipid membranes in its temperature dependence, in its much lower requirement for Ca2+, and in its Ca2+-specificity. Chemical and enzymatic modifications of the vesicle membrane indicate that glycoproteins may account for these differences

An ontology for strongly sustainable business models: Defining an enterprise framework compatible with natural and social science

Business is increasingly employing sustainability practices, aiming to improve environmental and social responsibility while maintaining and improving profitability. For many organizations, profit-oriented business models are a major constraint impeding progress in sustainability. A formally defined ontology, a model definition, for profit-oriented business models has been employed globally for several years. However, no equivalent ontology is available in research or practice that enables the description of strongly sustainable business models, as validated by ecological economics and derived from natural, social, and system sciences. We present a framework of strongly sustainable business model propositions and principles as findings from a transdisciplinary review of the literature. A comparative analysis was performed between the framework and the Osterwalder profit-oriented ontology for business models. We introduce an ontology that enables the description of successful strongly sustainable business models that resolves weaknesses and includes functionally necessary relationships