Cournot equilibrium uniqueness via demi-concavity

AbstractA family of oligopolies that possess a unique equilibrium was identified in the second authors doctoral dissertation. For such a family, it is therein specified a class of functions-economically related to the price function of a Cournot oligopoly – that satisfy a particular type of quasi-concavity. The first part of the present article (i) conceptualizes that type of quasi-concavity by introducing the notion of demi-concavity, (ii) considers two possible variants and (iii) provides some calculus properties. The second part, by relying on the results on demi-concavity, proves a Cournot equilibrium uniqueness theorem which is new for the journal literature and subsumes various results thereof. A third part shows an example that illustrates the novelty of the result

Quantum Hall - insulator transitions in lattice models with strong disorder

We report results of numerical studies of the integer quantum Hall effect in a tight binding model on a two-dimensional square lattice with non-interacting electrons, in the presence of a random potential as well as a uniform magnetic field applied perpendicular to the lattice. We consider field magnitudes such that the area per flux quantum is commensurate with the lattice structure. Topological properties of the single electron wave functions are used to identify current carrying states that are responsible for the quantized Hall conductance. We study the interplay between the magnetic field and the disorder, and find a universal pattern with which the current carrying states are destroyed by increasing disorder strength, and the system driven into an insulating state. We also discuss how to interpolate results of lattice models to the continuum limit. The relationship to previous theoretical and experimental studies of quantum Hall-insulator transitions in strongly disordered systems at low magnetic fields is discussed.Comment: 20 pages, 6 figure

The NOX toolbox: validating the role of NADPH oxidases in physiology and disease

Reactive oxygen species (ROS) are cellular signals but also disease triggers; their relative excess (oxidative stress) or shortage (reductive stress) compared to reducing equivalents are potentially deleterious. This may explain why antioxidants fail to combat diseases that correlate with oxidative stress. Instead, targeting of disease-relevant enzymatic ROS sources that leaves physiological ROS signaling unaffected may be more beneficial. NADPH oxidases are the only known enzyme family with the sole function to produce ROS. Of the catalytic NADPH oxidase subunits (NOX), NOX4 is the most widely distributed isoform. We provide here a critical review of the currently available experimental tools to assess the role of NOX and especially NOX4, i.e. knock-out mice, siRNAs, antibodies, and pharmacological inhibitors. We then focus on the characterization of the small molecule NADPH oxidase inhibitor, VAS2870, in vitro and in vivo, its specificity, selectivity, and possible mechanism of action. Finally, we discuss the validation of NOX4 as a potential therapeutic target for indications including stroke, heart failure, and fibrosis

Copernicus Marine Service ocean state report, issue 4

This is the final version. Available from Taylor & Francis via the DOI in this record. FCT/MCTE

Cournot equilibrium uniqueness via demi-concavity

AbstractA family of oligopolies that possess a unique equilibrium was identified in the second authors doctoral dissertation. For such a family, it is therein specified a class of functions-economically related to the price function of a Cournot oligopoly – that satisfy a particular type of quasi-concavity. The first part of the present article (i) conceptualizes that type of quasi-concavity by introducing the notion of demi-concavity, (ii) considers two possible variants and (iii) provides some calculus properties. The second part, by relying on the results on demi-concavity, proves a Cournot equilibrium uniqueness theorem which is new for the journal literature and subsumes various results thereof. A third part shows an example that illustrates the novelty of the result

Nash Equilibria of Transboundary Pollution Games

We reconsider the Nash equilibrium existence and uniqueness problem for transboundary pollution games. There is special attention for the equilibrium set E for effective compact transboundary pollution games with continuous strictly concave production functions, continuous convex damage cost functions and uniformly distributed transboundary pollution. For this case we show that E is a non-empty polytope and that for each country all equilibrium deposition levels are equal. If in addition each damage cost function is differentiable, then there is a unique equilibrium. The results are obtained by exploiting the aggregative structure of transboundary pollution games

Inferior Factor in Cournot Oligopoly Revisited

We reconsider the recent work by Okuguchi on (possibly asymmetric) Cournotian firms with two production factors, one of them being inferior. It is shown there that an increase in the price of the inferior factor does raise equilibrium industry output. In addition of providing a simpler and more rigorous proof of such a result, we generalize it to the case of technologies with s ≥ 2 factors and allow some firms not to use the inferior one