Predatory Exclusive Dealing

While the previous literature on exclusive dealing has been concerned with the question of how exclusive dealing can raise static profits, this paper analyzes the question of how exclusive dealing can be used to predate in a dynamic context. It is shown that exclusive dealing may arise even if it reduces static profits. Exclusivity provisions may not only allow excluding efficient competitors, but indeed are often a cheaper exclusionary tool than predatory pricing. This is the case if the prey's access to finance is not too limited. Furthermore, it is more likely that exclusive dealing is preferable compared to predatory pricing the more market power the predator has with respect to the prey

Predatory Exclusive Dealing

While the previous literature on exclusive dealing has been concerned with the question of how exclusive dealing can raise static profits, this paper analyzes the question of how exclusive dealing can be used to predate in a dynamic context. It is shown that exclusive dealing may arise even if it reduces static profits. Exclusivity provisions may not only allow excluding efficient competitors, but indeed are often a cheaper exclusionary tool than predatory pricing. This is the case if the prey's access to finance is not too limited. Furthermore, it is more likely that exclusive dealing is preferable compared to predatory pricing the more market power the predator has with respect to the prey.exclusive dealing; predation

Functional Dependencies for Object Databases: Motivation and Axiomatization

Object identification by abstract identifiers should be considered as a modeling and not as a database concept. This means that object identifiers are not appropriate for the access to specific objects using a database language. In this paper we discuss how the relational concept of a functional dependency can be adapted to object databases in order to get more convenient ways of accessing objects. Graph based object functional dependencies are proposed as a means to specify constraints between attributes and object types of an object schema. Value based identification criteria can be defined using a special type of object functional dependencies. Different definitions of satisfaction are given for these constraints, based on a so-called validation relation, and their relationships are investigated. These definitions are related to different forms of identification. Using the strongest notion of satisfaction, inference rules for the derivation of new dependencies are discussed with emphasis on the characteristics of rules combining two dependencies, like the transitivity rule. In addition to generalized relational rules further rules are needed, mainly concerned with transition from the object type level to the attribute level and vice versa

Der Frankfurter Hauptbahnhof und seine Rezeption im deutschen Bahnhofsbau des ausgehenden 19. und frühen 20. Jahrhunderts

Der Frankfurter Hauptbahnhof ist einer der wichtigsten Bahnhöfe des ausgehenden 19. Jahrhunderts in Deutschland. In seiner Nachfolge entstanden in mehreren deutschen Städte Bahnhöfe, die dem Frankfurter Beispiel verpflichtet sind. Diese Bahnhöfe wurden in ihrem Verhältnis zueinander untersucht

Not-So-Risky Business? Assessing the Risk of Integrating Large RPVs into the Current Air Traffic System

In spite of considerable efforts to commercialize large remotely piloted vehicles (RPV), an integration of these RPVs into the existing Air Transportation System (ATS) and Airspace Structure is pending. The purpose of this paper was to assess the risks of an exemplary integration of a Heron 1 type RPV into the existing European air space structure within the current regulatory framework and without the availability of sense and avoid technology. Six incident occurrence scenarios were investigated, based on a modified Fault Tree Analysis and Eurocontrol’s risk matrix. It was found that without the implementation of technological or procedural changes, an integration of a Heron 1 RPV presents a low to medium risk to air traffic. Recommended risk mitigation measures include equipping the RPV-operator with a recognized air picture, equipping the RPV with TCAS, installing a conventional telephone land line between the RPV-operator and air traffic control, and commencing the integration of large RPVs into air traffic at night. Further, simulation and flight based research is necessary to demonstrate whether these control measures would reduce the risk to an overall low level

Why Do Membranes of Some Unhealthy Cells Adopt a Cubic Architecture?

Nonlamellar lipid arrangements, including cubosomes, appear in unhealthy cells, e.g., when they are subject to stress, starvation, or viral infection. The bioactivity of cubosomes-nanoscale particles exhibiting bicontinuous cubic structures-versus more common vesicles is an unexplored area due to lack of suitable model systems. Here, glycodendrimercubosomes (GDCs)-sugar-presenting cubosomes assembled from Janus glycodendrimers by simple injection into buffer-are proposed as mimics of biological cubic membranes. The bicontinuous cubic GDC architecture has been demonstrated by electron tomography. The stability of these GDCs in buffer enabled studies on lectin-dependent agglutination, revealing significant differences compared with the vesicular glycodendrimersome (GDS) counterpart. In particular, GDCs showed an increased activity toward concanavalin A, as well as an increased sensitivity and selectivity toward two variants of banana lectins, a wild-type and a genetically modified variant, which is not exhibited by GDSs. These results suggest that cells may adapt under unhealthy conditions by undergoing a transformation from lamellar to cubic membranes as a method of defense

Interlaboratory study on rheological properties of cement pastes and reference substances: comparability of measurements performed with different rheometers and measurement geometries

This paper presents the results of an interlaboratory study of the rheological properties of cement paste and ultrasound gel as reference substance. The goal was to quantify the comparability and reproducibility of measurements of the Bingham parameters yield stress and plastic viscosity when measured on one specific paste composition and one particular ultrasound gel in different laboratories using different rheometers and measurement geometries. The procedures for both in preparing the cement paste and carrying out the rheological measurements on cement paste and ultrasound gel were carefully defined for all of the study’s participants. Different conversion schemes for comparing the results obtained with the different measurement setups are presented here and critically discussed. The procedure proposed in this paper ensured a reasonable comparability of the results with a coefficient of variation for the yield stress of 27% and for the plastic viscosity of 24%, despite the individual measurement series’ having been performed in different labs with different rheometers and measurement geometries

Exploring functional pairing between surface glycoconjugates and human galectins using programmable glycodendrimersomes

Precise translation of glycan-encoded information into cellular activity depends critically on highly specific functional pairing between glycans and their human lectin counter receptors. Sulfoglycolipids, such as sulfatides, are important glycolipid components of the biological membranes found in the nervous and immune systems. The optimal molecular and spatial design aspects of sulfated and nonsulfated glycans with high specificity for lectin-mediated bridging are unknown. To elucidate how different molecular and spatial aspects combine to ensure the high specificity of lectin-mediated bridging, a bottom-up toolbox is devised. To this end, negatively surface-charged glycodendrimersomes (GDSs), of different nanoscale dimensions, containing sulfo-lactose groups are self-assembled in buffer from a synthetic sulfatide mimic: Janus glycodendrimer (JGD) containing a 3′-O-sulfo-lactose headgroup. Also prepared for comparative analysis are GDSs with nonsulfated lactose, a common epitope of human membranes. These self-assembled GDSs are employed in aggregation assays with 15 galectins, comprising disease-related human galectins, and other natural and engineered variants from four families, having homodimeric, heterodimeric, and chimera architectures. There are pronounced differences in aggregation capacity between human homodimeric and heterodimeric galectins, and also with respect to their responsiveness to the charge of carbohydrate-derived ligand. Assays reveal strong differential impact of ligand surface charge and density, as well as lectin concentration and structure, on the extent of surface cross-linking. These findings demonstrate how synthetic JGD-headgroup tailoring teamed with protein engineering and network assays can help explain how molecular matchmaking operates in the cellular context of glycan and lectin complexity

Strangeness Suppression in Proton-Proton Collisions

We analyse strangeness production in proton-proton (pp) collisions at SPS and RHIC energies, using the recently advanced NeXus approach. After having verified that the model reproduces well the existing data, we interpret the results: strangeness is suppressed in proton-proton collisions at SPS energy as compared to electron-positron (e+e-) annihilation due to the limited masses of the strings produced in the reaction, whereas high energy pp and e+e- collisions agree quantitatively . Thus strangeness suppression at SPS energies is a consequence of the limited phase-space available in string fragmentation.Comment: 7 Figures, 4 Page

Loss of Roquin induces early death and immune deregulation but not autoimmunity

Deletion of Roquin in T or B cells, or in the entire hematopoietic system of mice, alters immune homeostasis but does not result in autoimmunity