A dynamic cournot-nash equilibrium in fishery: The effects of entry

A dynamic Cournot-Nash equilibrium of the fish war between two countries has been derived and its steady-state behavior studied by Levhari and Mirman on the basis of a discrete dynamic programming method. In this paper we shall consider an n-country extension of Levhari-Mirman fish war model. We shall derive the Cournot-Nash equilibrium and its steady-state value to analyze the effects of entry (or exit) in fish war. A comparison is made between in dividual management of fishery by each country and joint management by all countries.

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Riassunto In questo lavoro si considera l'estensione, al caso din paesi concorrenti, del modello concorrenziale dell'attività peschereccia proposto da Levhari e Mirman. Viene derivata la configurazione di equilibrio di Cournot-Nash e si calcola il suo valore stazionario per analizzare l'effetto d'entrata (o d'uscita) di un agente nella attività concorrenziale.Viene infine fatto un confronto tra la conduzione individuale della pesca in ogni singolo paese e la conduzione congiunta di tutti i paesi considerati.

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Versione definitiva pervenuta il 17-1-81     

Cost-effectiveness of mechanical thrombectomy for acute ischemic stroke: an Australian payer perspective

Aims: The goal of this study was to assess the cost-effectiveness of mechanical thrombectomy (MT) for acute ischemic stroke (AIS) from an Australian payer perspective.

Methods: This study used a Markov model that employed a life-time time horizon, modeling patients from symptom onset of stroke until end of life. Clinical efficacy and safety data were taken from an individual patient level data (IPD) meta-analysis of clinical studies. The treatment effect of MT compared to usual care was measured by changes in modified Rankin Score (mRS). Post-treatment mRS scores were used to determine short- and long-term stroke care costs. Treatment costs were modeled, with health state utility values determined by literature review. All analyses were conducted using Microsoft Excel.

Results: In comparison to usual care, MT is associated with higher costs ($10,666 per patient) and additional quality-adjusted life years (QALYs) (0.8281 per patient), resulting in an incremental cost per QALY of $12,880. Sensitivity analyses demonstrated the reliability of the base case results across a range of assumptions. The higher cost associated with MT is, to an extent, offset by the cost savings resulting from lower stroke care costs due to improved patient outcomes. The life-time cost savings in terms of stroke care costs are estimated to be more than $8,000 per patient for patients who had received MT in combination with usual care.

Limitations: Stroke care costs based on patient disability/functional level were not available and were derived. As a consequence, long-term care costs for patients with poorer outcomes may be under-estimated. Patient outcomes at 90 days were extrapolated to a lifetime horizon, but this approach was supported by long-term evidence on stroke survival.

Conclusions: Mechanical thrombectomy is a cost-effective treatment option for AIS, with clinical benefits translating to short- and long-term cost benefits. This analysis supports rapid update of stroke care pathways to incorporate this therapy as a treatment option.     

The weak core of simple games with ordinal preferences: implementation in Nash equilibrium

In a simple game, coalitions belonging to a given class are “absolutely powerful” while others have no power. We attempt to make this distinction operational. Toward this end, we propose two axioms on social choice correspondences, Strong Non-Discrimination and Exclusion. Strong Non-Discrimination describes circumstances under which certain coalitions, the losing coalitions, have no influence over social choice. Exclusion requires that there are situations in which certain coalitions, the winning coalitions, can exercise their power. We show that the weak core correspondence is the minimal correspondence satisfying Maskin Monotonicity and Strong Non-Discrimination. We also show that the weak core is the unique correspondence satisfying Nash implementability, Strong Non-Discrimination, and Exclusion.     

Partial privatization in mixed duopoly with price and quality competition

We analyze price and quality competition in a mixed duopoly in which a profit-maximizing private firm competes against a state-owned public firm. We first show that the welfare-maximizing public firm provides a lower quality product than the private firm when they are equally efficient. In order to maximize social welfare, government manipulates the objective of the public firm that is given by a convex combination of profits and social welfare. It is demonstrated that an optimal incentive of the public firm is welfare maximization under the absence of quality competition, but it is neither welfare maximization nor profit maximization under the presence of quality competition. The result supports a completely mixed objective between welfare and profit maximizations or partial privatization of the public firm.