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Simulating conventions and norms under local interactions and imitation
Get PDFThis paper is based on Ille 2013. Both papers analyze the same model, but in contrast, this paper does not provide an analytical solution but rather resorts to simulations. This allows the reader, who is familiar with the former article, to retrace the results more thoroughly and without the requirement of a sophisticated mathematical background. Additionally, this paper illustrates the dynamics of the setting. Focus is placed on 2 × 2 Nash coordination games on a two-dimensional lattice. Players imitate the most success- ful player in their reference group (Moore neighborhood) in the former period. Similarly individual pay-off is only defined by the current strategic choice of this reference group. We observe that the long-term convention is defined by a trade-off between risk and efficiency and that player population converges to the Pareto dominant though risk inferior convention for a broad range of pay-off configurations. In the case of two player populations, the long-term convention is defined by the equilibrium granting the highest benefit to one population. Consequently, conventions illustrate a tendency to be inegalitarian
Emerging key roles for P2X receptors in the kidney
Get PDFP2X ionotropic non-selective cation channels are expressed throughout the kidney and are activated in a paracrine or autocrine manner following the binding of extracellular ATP and related extracellular nucleotides. Whilst there is a wealth of literature describing a regulatory role of P2 receptors (P2R) in the kidney, there are significantly less data on the regulatory role of P2X receptors (P2XR) compared with that described for metabotropic P2Y. Much of the historical literature describing a role for P2XR in the kidney has focused heavily on the role of P2X1R in the autoregulation of renal blood flow. More recently, however, there has been a plethora of manuscripts providing compelling evidence for additional roles for P2XR in both kidney health and disease. This review summarizes the current evidence for the involvement of P2XR in the regulation of renal tubular and vascular function, and highlights the novel data describing their putative roles in regulating physiological and pathophysiological processes in the kidney
National Perspectives on Russia: Bulgaria
No full textWe inhabit a space governed by over 1,700 international organizations, each seeking to stimulate and enhance co-operation and co-ordination amongst nation states to an ever greater extent (Union of International Associations 2001:2586). Arguably, the role of international organizations has never been more prominent in politics than it is today, as they have come to assume the role of principal over their once traditional embodiment of an agent (Finnemore 1993). Consequently, their impact on both international relations and domestic policy formation has profoundly increased since the end of the First World War. This is especially true of the European integration project. The unprecedented role the Commission played in the integration of states into the European Communities has had an important impact on the development of cognitive structures of domestic agents through the process of socialization amongst member countries (Finnemore 1993:50–51).This incidence further increased with the end of the Cold War. The ensuing power vacuum necessitated that the political geography of the European continent be redrawn once again. The collapse of the Soviet Union and the pull of both the European Union and NATO through the carrot-and-stick approach (Buller 2000) resulted in profound foreign policy reorientations in the COMECON (Council for Mutual Economic Assistance) states of the former Soviet bloc
Pays de l'Ocean: "Aquatopia: The Imaginary of the Ocean Deep"
Get PDFA review of "Aquatopia: The Imaginary of the Ocean Deep", an exhibition of the works of several artists, including Dorothy Cross, Simon Starling, and Anjalika Sagan, at the Tate St Ives in Cornwall England
Extracellular ATP signaling in equine digital blood vessels
Get PDFThe functional distribution of ATP-activated P2 receptors is well characterized for many blood vessels, but not in the equine digital vasculature, which is a superficial vascular bed that displays thermoregulatory functions and has been implicated in ischemia-reperfusion injuries of the hoof. Isolated equine digital arteries (EDA) and veins (EDV) were submitted to isometric tension studies, whereby electric field stimulation (EFS) and concentration-response curves to exogenously applied agonists were constructed under low tone conditions. Additionally, immunofluorescent localization of P2X and P2Y receptor subtypes was performed. EFS-induced constriction was abolished by tetrodotoxin (1 μM, n=4). Endothelium denudation did not modify the EFS-induced constriction (n=3). The EFS-induced constriction in EDA was inhibited by phentolamine (67.7±1.8%, n=6; 10 μM), and by the non-selective P2 receptor antagonist suramin (46.2±1.3%, n=6; 10 μM). EFS-induced constriction in EDV was reduced by suramin (48.2±2.4%, n=6; 10 μM), the P2 receptor antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (58.3±4.5%, n=6; 10 μM), and phentolamine (23.2±2.5%, n=6; 10 μM). Exogenous methoxamine and ATP mimicked EFS-induced constriction in EDA and EDV. Immunostaining for P2X1, P2X2 and P2X3, and, for P2X1 and P2X7 receptor subunits were observed in EDA and EDV smooth muscle and adventitia, respectively. ATP and noradrenaline are co-transmitters in sympathetic nerves supplying the equine digital vasculature, noradrenaline being the dominant agonist in EDA, and ATP in EDV. In conclusion, P2X receptors mediate vasoconstriction in EDA and EDV, although different P2X subunits are involved in these vessels. The physiological significance of this finding in relation to thermoregulatory functions and equine laminitis is discussed
