Oligopoly meets oligopsony: The case of permits

This paper derives market equilibria (in demand functions and in bidding strategies) between oligopolists and oligopsonists in a market with intermediates and no competition in final markets. To the best of my knowledge, this theme has not been explored, despite two observations: Firstly, the commonly applied framework of non-competitive and competitive fringe firms has implausible properties for the limit of purely strategic players. Secondly, real world cases correspond at least potentially to such strategic interactions, e.g., non-competitive players selling and buying permits (CO₂ and SO₂). The major implications are that these non-competitive markets are characterized by a kind of double marginalization (on the demand and the supply side) resulting in too little trade and wrong price signals.     

Agronomic and economic potential of manure in Bolivian valleys and highlands

The staple diet of the rural population of Bolivia consists of potatoes and maize. Spanish colonization and agrarian reform radically changed the Inca agricultural system. The use of imported fertilizers in potato growing is becoming more widespread. Average potato production is failing, and in 1980 stood at 4.67 tons ha⁻¹. In 1982, potato farmers needed to produce more than double the amount of potatoes compared with the previous year in order to buy the same quantity of imported fertilizer. The results of comparative experiments with fresh and composted organic manures and chemical fertilizers carried out in two potato-producing regions with different climatic and soil characteristics are shown in this paper. At high altitudes with acid soils, fresh manure and chemical fertilizer gave good results. On the other hand, higher yields were obtained with compost in the valley of Cochabamba, which has a neutral soil. Organic manures are deficient in phosphorus. The use of phosphate rock and bone meal is proposed, both of which can be obtained locally, to increase the phosphorus content of organic manures.     

Portrait of an Asian stalk-eyed fly

Diopsid flies have eyes set on stalks which are in some cases so long that the distance between the eyes exceeds the body length. These conspicuous structures have given rise to much speculation about their adaptive value, but there are very few actual observations by which to judge these hypotheses.Cyrtodiopsis whitei Curran lives in the tropical rainforest of Malaysia. We describe a number of aspects of its morphology and biology, some functional properties of the eye, and the ritualized fights between males, by which harems are acquired. The evolutionary significance of the eyestalks is discussed: they represent structures subjected to a double selection pressure; they are an adaptation by which a sensory system is better matched to the special problems encountered in a densely structured habitat (in that the field of view is extended and the ability to estimate distance and size and to identify objects at a large distance is improved), also they act as key stimulus for species recognition and as releaser for intraspecific behaviour.