A note on the ecological-economic modelling of marine reserves in fisheries

This paper gives an overview of the bioeconomic modelling of marine reserves, and illustrates how economists have responded to the modelling results found in the ecological literature. The economic analysis is shown to be far more pessimistic with regards to the potential of marine reserves as a fisheries management tool, than what one finds in the purely ecological analysis, the reason being the latter's neglect of issues such as discounting and economic incentive behaviour. However, economic analysis, despite some of it being relatively advanced with regards to spatiality, is still simplistic with regards to for instance ecosystem and habitat content. A simple expansion of the existing bioeconomic models with regards to positive habitat effects of area closures is presented and analysed, showing room for improved results from marine reserve implementation as compared to the existing analysis.     

Rich Nations, Poor Nations: How Much Can Multiple Equilibria Explain?

This paper asks whether the income gap between rich and poor nations can be explained by multiple equilibria. We explore the quantitative implications of a simple two-sector general equilibrium model that gives rise to multiplicity, and calibrate the model for 127 countries. Under the assumptions of the model, around a quarter of the world’s economies are found to be in a low output equilibrium. We also find that, since the output gains associated with an equilibrium switch are sizeable, the model can explain between 15 and 25% of the variation in the logarithm of GDP per worker across countries.     

The Productivity of US States since 1880

This study uses state-level variation in labor productivity levels at twenty-year intervals between 1880 and 1980 to examine the relative importance of institutional and geographical influences in explaining observed and persistent differences in standards of living over time and across regions. Focusing on fundamental rather than proximate influences, we find that both institutional characteristics and some physical geography characteristics account for a high proportion of the differences in state productivity levels: states with navigable waterways, a large minerals endowment, and no slaves in 1860, on average, had higher labor productivity levels throughout the sample period. However, we find little support for two other influences that have previously received attention—climate and latitude.     

Trucking deregulation and highway safety: The effect of the 1980 Motor Carrier Act

The relationship between deregulation in the trucking industry and highway safety is an important economic and social issue. Analyses thus far have concentrated on the relationship between the downward pressure imposed on freight rates by deregulation and total safety investment by firms. Two issues which have been ignored are the effects that deregulation had on route carriage restrictions and total firm mileage. We show that the inclusion of these factors yields a model in which the relationship between motor carrier deregulation and highway safety is dependent upon the relative effects of all three factors. Estimation of the model using accident data implies that trucking deregulation did not deteriorate highway safety and may have actually improved it.     

Some comparative-statics results for nonlinear input-output models of a multisectored economy,and related results for nonlinear price-demand relations

For a nonlinear version of the linear input-output model of Leontief, we consider the effect, on the vector x of total gross outputs, of changes in the components of the final-demand vector c. For example, it is shown that, for a certain important class of models, the “large-change elasticity” of any component of x, with respect to any component of c, is less than or equal to unity. Some similar results are proved concerning properties of nonlinear price-demand relations for the case in which all goods are weak gross substitutes. Unlike earlier work in this general area, we do not introduce hypotheses concerning the indecomposability or homogeneity of certain mappings. For that reason, the results are valid for the price-demand relation for a single firm, or for any collection of firms.     

The dynamics of some duopoly games involving the Market Share and Nichol strategies

The paper analyses the dynamics of some duopoly output games involving the Cournot, Market-Share and Nichol strategies. The model assumes linear price and cost functions and supposes that outputs are adjusted instantaneously at discrete time intervals. For all games considered, equilibrium is either reached after a finite number of moves or a stable approach to equilibrium occurs as t → ∞. In fact, apart from a few uninteresting cases, arising from the oversimplified form of the Market-Share strategy, all equilibrium points lie on specified parts of the firms' Cournot loci.