On the Social Desirability of Patents for Sequential Innovations in a Vertically Differentiated Market

We consider a market for vertically differentiated goods where firms enter over time, after having developed innovations characterised by different quality levels. We show that patent height and length interact to determine the ultimate emergence of duopoly. In general, imposing quality improvements on later entrants entails the persistence of monopoly, while a duopoly equilibrium emerges when the second innovator is allowed to produce a sufficiently inferior quality and the patent protection granted to the first innovator is not too long-lasting.     

The use of organized commodity markets to manage food import price instability and risk

The article explores the possibility of insuring the price risks of wheat and maize imports of low‐income food‐deficit countries (LIFDCs). Optimal strategies for an importing agent, who hedges with futures and options are derived, based on the objective of minimizing the unpredictability of import bills. Ex post simulations for a set of LIFDCs are run on wheat and maize imports hedged with futures and options in the Chicago Board of Trade, to explore the extent to which hedging reduces the unpredictability in import bills. Simulations encompass both periods of normal price behavior, as well as the period of global upheaval that occurred in 2007 and 2008. Results show that hedging with futures alone affords agents considerable opportunities for reducing import cost unpredictability, and the same holds with options, albeit, to a lesser extent. However, during the recent price spike of 2007–2008, hedging with options would have increased the unpredictability of some countries’ maize import bills, due to the combination of erratic import patterns and pronounced market uncertainty.     

The breakdown of the IS–LM synthesis: implications for post-Keynesian economic theory

The monetarist and the new classical economics attack routed the IS–LM version of Keynesian theory and the large scale econometric models from the centre of macroeconomic research. However monetarism and the new classical economics were more successful as a critique of the IS–LM orthodoxy than as a basis for fruitful research and policy analysis.

Post-Keynesian economists also attack the IS–LM orthodoxy, mainly because it misspecified ‘… the economic society in which we actually live’. Post-Keynesians that emphasized financial and labour markets argued that properties of the real world economy made instability normal results ofmarket interactions.

The vacuum in main line theory that developed as the shortcomings of monetarism became evident led to a revival of interest in basic Keynesian propositions. This has spawned what is now labeled a new Keynesian economics. New Keynesian economists conform to the modeling standards set by the new classical rational expectations school but claim to get Keynesian results. To a degree these results are compatible with propositions of post-Keynesian economics.

It is suggested that a convergence between the new and the post-Keynesian economics can be expected, and the result is likely to be fruitful.     

Probabilistically constrained models for efficiency and dominance in DEA

This paper proposes a stochastic model for data envelopment analysis (DEA), based on the theory of joint probabilistic constraints, which can be used with general multivariate distribution functions. The key assumption is that the random variables representative of the uncertain data follow a discrete distribution or that a discrete approximation of continuous distribution is available. Under this assumption, mixed integer linear models are formulated to tackle, rather originally, dependencies among DMUs inputs, outputs and inputs–outputs through the theory of joint probabilistic constraints. The features of the model are illustrated through an application for the performance evaluation of screening units.     

Evaluation of a maltodextrin gel as a partial replacement for fat in a high‐ratio white‐layer cake

The performance of maltodextrin gel as a replacement (25%, 50%, 75% and 100%) for shortening along with sucrose and high fructose corn syrup‐90 (HFCS‐90), adjusted for sweetness in each treatment, was evaluated in a high‐ratio white‐layer cake formulation. Two controls were used as a reference to fat‐replaced cakes: control A (100% fat and 100% sucrose) and control B (100% fat with 50% sucrose/50% HFCS‐90), which closely matched the sugar system of the fat‐replaced cakes. Volume of cakes showed that treatment F (100% fat‐substituted) was significantly (P < 0.05) different from the other treatments. Crust and crumb L‐ and b‐values indicated that control B produced a dark crust (P < 0.05) with a light crumb (P < 0.05) whereas treatment E (75% fat substituted) produced a light crust (P < 0.05) and treatment F a darker crumb (P < 0.05) with a significantly (P < 0.05) higher moisture content. Degree of staling significantly (P < 0.05) increased over time for all treatments. Sensory results indicated that treatment F produced a significantly (P < 0.05) moister, less adhesive and cohesive cake. Tenderness and sweetness scores indicated that treatments E and F were significantly (P < 0.05) tougher and less sweet, respectively, when compared with the other treatments. Results from both the physical and sensory analyses indicated that the combination of maltodextrin gel up to a 75% reduction for shortening and sucrose/HFCS‐90 resulted in satisfactory cakes.     

Ghettos as tourism attractions

If increased historic preservation, restoration, and reconstruction reflects the maturation of America, they also reflect controversy over what is preserved, by whom, and to what ends. Using Little Italy as a case in point, this paper explores issues likely to arise and potential implications when urban areas depicting an ethnic or racial heritage are preserved for the purposes of tourism. That such areas were initially oppressive and restrictive ghettos portrayed by derogatory stereotypes of their residents, particularly poses the question of whether those images and the attitudes they stimulated are preserved, restored, or reconstructed along with material artifacts.     

Disaggregation of excess demand and comparative statics with incomplete markets and nominal assets

Summary. We prove that locally, Walras' law and homogeneity characterize the structure of market excess demand functions when financial markets are incomplete and assets' returns are nominal. The method of proof is substantially different from all existing arguments as the properties of individual demand are also different. We show that this result has important implications and is part of a more general result that excess demand is an essentially arbitrary function not just of prices, but also of the exogenous parameters of the economy as asset returns, preferences, and endowments. Thus locally the equilibrium manifold, relating equilibrium prices to these parameters has also no structure. Received: September 17, 1996; revised version: November 7, 1997     

Risk management and finance along value chains of Small Island Developing States. Evidence from the Caribbean and the Pacific

The paper analyses agricultural risks and risk management in selected Small Island Developing States which are part of the African Caribbean Pacific country group. Focus is on the value chains of fruits, vegetables and spices. A survey was conducted in Grenada, Jamaica, Fiji and Vanuatu, aimed at identifying sources of risk which are most important to value chain stakeholders; the nature and quality of existing and potential risk management mechanisms; and the possibility of enhancing them in view of improving the functioning of the value chains. The sample included farmers, processors, traders, retailers, extension agents, Government officials and private services providers. Results reveal limited ability to handle price and production variability, due to lack of both horizontal and vertical co-ordination along value chains, reduced use of support services, notably credit and underinvestment in equipment. In addition, lack of demand contributes to make insurance markets incomplete and characterised by undersupply or lack of customised products. Promoting light forms of vertical and horizontal co-ordination, such as production contracts and producers’ associations, as well as value chain-based credit and finance may address some of the issues highlighted.