We develop a dynamic model of a fishery which simultaneously incorporates random stock growth and costly capital adjustment. Numerical techniques are used to solve for the resource-rent-maximizing harvest and capital investment policies. Capital rigidities bring diminishing marginal returns to the current period harvest, and introduce an incentive to smooth the catch over time. With density dependent stock growth, however, catch smoothing increases stock variability resulting in reduced average yields. The optimal management policy balances the catch smoothing benefits against yield loss. We calibrate the model to the Alaskan pacific halibut fishery to demonstrate the main insights.
Recent genome-wide association studies have implicated the tumor necrosis factor receptor-associated factor 3-interacting protein 2 (TRAF3IP2) gene and its product, nuclear factor-kappa-B activator 1 (Act1), in the development of psoriatic arthritis (PsA). The high level of sequence homology of the TRAF3IP2 (Act1) gene across the animal kingdom and the presence of the Act1 protein in multiple cell types strongly suggest that the protein is of importance in normal cellular function. Act1 is an adaptor protein for the interleukin-17 (IL-17) receptor, and recent observations have highlighted the significance of IL-17 signaling and localized inflammation in autoimmune diseases. This review summarizes data from recent genome-wide association studies as well as immunological and molecular investigations of Act1. Together, these studies provide new insight into the role of IL-17 signaling in PsA. It is well established that IL-17 activation of tumor necrosis factor receptor-associated factor 6 (TRAF6) signaling pathways normally leads to nuclear factor-kappa-B-mediated inflammation. However, the dominant PsA-associated TRAF3IP2 (Act1) gene single-nucleotide polymorphism (rs33980500) results in decreased binding of Act1 to TRAF6. This key mutation in Act1 could lead to a greater association of the IL-17 receptor with TRAF2/TRAF5 and this in turn suggests an alternative function for IL-17 in PsA. The recent observations described and discussed in this review raise the clinically significant possibility of redefining the immunological role of IL-17 in PsA and provide a basis for defining future studies to elucidate the molecular and cellular functions of Act1.
Inflation in many Organisation for Economic Co-operation and Development (OECD) countries was low in the 1960s, rose for a time before peaking in the 1970s or early 1980s, and then fell back to initial levels. This paper shows that a simple time inconsistency model of monetary policy does not explain OECD inflation outcomes, except in the United States. The hypothesis that time inconsistency mattered only in earlier decades fits the data no better than the baseline model. We find some, albeit limited support for a model in which inflation spills over from the United States into other countries as a result of exchange rate targeting. Copyright (c)2008 The Ohio State University.
Leading economic models of crime assume that potential criminals achieve their ends by criminal means or not at all. We develop a framework in which potential criminals can also attain their objectives through voluntary trade. Our framework helps explain several features of the legal system that have proven to be problematic for the canonical approach: why optimal sanctions should be increasing in an individual's criminal history, and why necessity may be a partial defense in some situations. Finally, the inclusion of a voluntary trade option makes the maximization of a utilitarian welfare function identical to minimizing the costs of crime, implying that a long-standing controversy in the literature is, in part, an artifact of the assumption that criminals face a binary choice set. (JEL K42, D60, H00)
Recent theoretical work shows that changes in the volatility of inflation and/or unemployment affect equilibrium inflation outcomes when the central banker's loss function is asymmetric. We show that previous evidence offered in support of the proposition that the volatility of unemployment helps explain inflation outcomes suffers from a spurious regression problem. Once this problem is controlled for, the evidence suggests that the volatility of unemployment does not help explain inflation outcomes. There is some evidence of a relationship between inflation and its volatility, but the data is not strongly supportive of the view that asymmetric central bank preferences are an important driver of inflation.
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