Iceberg transport technologies in spatial competition. Hotelling reborn

Transport costs in address models of differentiation are usually modeled as separable of the consumption commodity and with a parametric price. However, there are many sectors in an economy where such modeling is not satisfactory either because transportation is supplied under oligopolistic conditions or because there is a difference (loss) between the amount delivered at the point of production and the amount received at the point of consumption. This paper is a first attempt to tackle these issues proposing to study competition in spatial models using an iceberg-like transport cost technology allowing for concave and convex melting functions.

Trade liberalization, competition and growth

Increasing evidence support the claim that international trade enhances innovation and productivity growth through an increase in competition. This paper develops a two-country endogenous growth model, with firm specific R&D and a continuum of oligopolistic sectors under Cournot competition to provide a theoretical support to this claim. Since countries are assumed to produce the same set of varieties, trade openness makes markets more competitive, reducing prices and increasing quantities. Under Cournot competition, trade is pro-competitive. Since firms undertake cost reducing innovations, the increase in production induced by a more competitive market push firms to innovate more. Consequently, a reduction on trade barriers enhances growth by reducing domestic firm's market power.

Interespecific competition between Peckia chrysostoma and Adiscochaeta ingens (Diptera: Sarcophagidae) larvae reared in laboratory

Groups of 10 and 20 first instar larvae of Peckia chrysostoma (Wiedemann, 1830) were combined in a proteic source media with groups of the same number of first instar larvae of Adiscochaeta ingens (Walker, 1849) under the environmental conditions of Rio de Janeiro, RJ, Brasil. P. chrysostoma and A. ingens obtained average competitive potentials of 94.0 ± 2.0% and 31.0 ± 5.0% respectively. In the second experiment, larvae of P. chrysostoma were introduced approximately 15 hr after the introduction of A. ingens larvae (whose majority had already passed to the second instar) in the media. The corresponding average competitive potential of P. chrysostoma (82.0 ± 2.0%) was decreased when compared to the first experiment, but still greater than that of A. ingens (64.5 ± 9.5%). The competitive potential of A. ingens, however, increased significatively, demonstrating the influence of its previous colonization in the media for achieving a higher viability. In both experiments the competitive potential of P. chrysostoma was greater and similar to observations cited in the literature. Control-groups of each species were observed, individually, for the comparison. The mean value obtained for P. chrysostoma was 94.0 ± 3.7% (0.0% [experiment 1] and only 12.8% [experiment 2] greater than the average competitive factor). For A. ingens the average was 86.0 ± 7.3% (64.0% [experiment 1] and 25.0% [experiment 2] greater than average competitive factor).

Monopolistic competition and different wage setting systems

In this paper we match the static disequilibrium unemployment model without frictions in the labor market and monopolistic competition with an infinite horizon model of growth. We compare the wages set at the firm, sector and national (centralized) levels, their unemployment rates and growth of the economic variables, for the Cobb-Douglas production function, in order to see under wich conditions the inverse U hypothesis between unemployment and centralization of wage bargain is confirmed. We also analyze, in the three wage setting systems, the effect of an increase in the monopoly power on employment and growth.

Trade, firm selection, and innovation: the competition channel

The availability of rich firm-level data sets has recently led researchers to uncover new evidence on the effects of trade liberalization. First, trade openness forces the least productive firms to exit the market. Secondly, it induces surviving firms to increase their innovation efforts and thirdly, it increases the degree of product market competition. In this paper we propose a model aimed at providing a coherent interpretation of these findings. We introducing firm heterogeneity into an innovation-driven growth model, where incumbent firms operating in oligopolistic industries perform cost-reducing innovations. In this framework, trade liberalization leads to higher product market competition, lower markups and higher quantity produced. These changes in markups and quantities, in turn, promote innovation and productivity growth through a direct competition effect, based on the increase in the size of the market, and a selection effect, produced by the reallocation of resources towards more productive firms. Calibrated to match US aggregate and firm-level statistics, the model predicts that a 10 percent reduction in variable trade costs reduces markups by 1:15 percent, firm surviving probabilities by 1 percent, and induces an increase in productivity growth of about 13 percent. More than 90 percent of the trade-induced growth increase can be attributed to the selection effect.

Current advances on the study of snail-snail interactions, with special emphasis on competition process

Field work research on population dynamic of snails from the regions of Belo Horizonte and Lagoa Santa give much information about interactions among two or more species of mollusks: Pomacea haustrum, Biomphalaria glabrata, B. tenagophila, B. straminea and Melanoides tuberculata. Data ranging from two years to several decades ago suggest that the Pampulha reservoir is like a cemetery of B. glabrata and B. straminea, species that coexist for more than 14 years in a small part of a stream, whereas only B. glabrata lives in all the streams of the basin. In the last ten to twenty years B. tenagophila has coexisted with P. haustrum and M. tuberculata in the Serra Verde ponds and in the Pampulha dam. However these species have not settled in any of the brooks, except temporarily. The data suggest that the kind of biotope and the habitat conditions are decisive factors for the permanence of each species in its preferencial biotope. B. glabrata, natural from streams and riverheads, quickly disappears from the reservoirs and ponds where it coexists with other species for a short time, independently of the competitive process. Competition needs to be better studied, since in Central America and Caribean islands this kind of study has favored the biological control of planorbid species.

Social rules govern vocal competition in the barn owl

To resolve the share of limited resources, animals often compete through exchange of signals about their relative motivation to compete. When two competitors are similarly motivated, the resolution of conflicts may be achieved in the course of an interactive process. In barn owls, Tyto alba, in which siblings vocally compete during the prolonged absence of parents over access to the next delivered food item, we investigated what governs the decision to leave or enter a contest, and at which level. Siblings alternated periods during which one of the two individuals vocalized more than the other. Individuals followed turn-taking rules to interrupt each other and momentarily dominate the vocal competition. These social rules were weakly sensitive to hunger level and age hierarchy. Hence, the investment in a conflict is determined not only by need and resource-holding potential, but also by social interactions. The use of turn-taking rules governing individual vocal investment has rarely been shown in a competitive context. We hypothesized that these rules would allow individuals to remain alert to one another's motivation while maintaining the cost of vocalizing at the lowest level.

Party competition in regional elections: a framework for analysis

Whilst scholars have long recognised that processes of decentralisation create new regional arenas where distinct patterns of party competition are likely to emerge, there has been little systematic analysis of the dynamics of such competition. This working paper thus proposes a framework for analysing party competition between regional branches of state-wide parties, and autonomist parties, in regional arenas. Firstly, the different strategies political parties may adopt in response to their perceptions of voter preferences and to the strategies pursued by their competitors are identified. Secondly, different factors that impact on parties' strategic choices, and which may constrain a party's ability to select electorally optimal strategies in a given political context, are proposed.

No experimental evidence that sibling competition induces young to switch nests in the colonial Alpine swift, Apus melba

Adoption is frequent in colonial animals where opportunities for dependent young to receive care from nonbiological parents are high. The departure of dependent young from their original family to seek adoption in neighbouring families is thought to be induced by sibling competition for access to limited resources provided by poor-quality parents. We tested this hypothesis in the colonial Alpine swift by manipulating the number of young reared per brood, with the prediction that offspring from enlarged broods switch nests more frequently than those from reduced broods. Although nestling swifts hatch with little locomotor activity, from 20 days until their first flight at 50-70 days they frequently move out of their nests to seek adoption in neighbouring families. Although nestlings reared in experimentally enlarged broods were lighter and their body mass at day 20 after hatching was more variable than in nestlings reared in reduced broods, there was no difference between the two treatments in the frequency of nests switching and in the age when nestlings switched nests for the first time. However, consistent with other evidence that nest switching by nestling swifts evolved as a strategy to reduce ectoparasite load, young from broods with naturally high numbers of the ectoparasitic louse fly Crataerina melbae were more prone to switch nests. This shows that ectoparasitism rather than sibling competition is a key proximate factor promoting the evolution of nest switching in the colonial Alpine swift. (c) 2006 The Association for the Study of Animal Behaviour Published by Elsevier Ltd. All rights reserved.

What if there was a stronger pharmaceutical price competition in Spain? When regulation has a similar effect to collusion

This paper examines statins competition in the Spanish pharmaceutical market, where prices are highly regulated, and simulates a situation in which there is unrestricted price competition. A nested logit demand model is estimated with a panel of monthly data for pharmaceuticals prescribed from 1997 to 2005. The simulation indicates that the regulation of prices is similar in its effects to cooperation among producers, since the regulated prices are close to those that would be observed in a scenario of perfect collusion. Freedom to set prices and a regulatory framework with appropriate incentives would result in a general reduction in prices and may make the current veiled competition in the form of discounts to pharmacists become more visible. The decrease in prices would be partially offset by an increase in consumption but the net effect would be an overall decrease in expenditure. The counterfactual set-up would also lead to important changes in the market shares of both manufacturers and active ingredients, and a reversal of generic drugs. Therefore, pro-competitive regulation would be welfare-enhancing but would imply winners and losers.

Generic drugs in Spain: price competition vs. moral hazard

This paper examines competition between generic and brand-name drugs in the regulated Spanish pharmaceutical market. A nested logit demand model is specified for the three most consumed therapeutic subgroups in Spain: statins (anticholesterol), selective serotonin reuptake inhibitors (antidepressants) and proton pump inhibitors (antiulcers). The model is estimated with instrumental variables from a panel of monthly prescription data from 1999 to 2005. The dataset distinguishes between three different levels of patients’ copayments within the prescriptions and the results show that the greater the level of insurance that the patient has (and therefore the lower the patient’s copayment), the lower the proportion of generic prescriptions made by physicians. It seems that the low level of copayment has delayed the penetration of generics into the Spanish market. Additionally, the estimation of the demand model suggests that the substitution rules and promotional efforts associated with the reference pricing system have increased generic market share, and that being among the first generic entrants has an additional positive effect.

Plantar pressures in the tennis serve.

In-shoe loading patterns were examined in each foot (back and front) separately during two types of tennis serve [first (or flat) and second (or twist) serve] and two service stance styles [foot-up (back foot is moved forward next to front foot for push-off) and foot-back (feet remain at the same relative level)]. Ten competitive tennis players completed five trials for each type of serve and service stance style in random order. Plantar pressure distribution was recorded using Pedar insoles divided into nine areas for analysis. Mean and peak pressures (+15.2%, P < 0.01 and +12.8%, P < 0.05) as well as maximal forces (+20.2%, P < 0.01) were higher under the lateral forefoot of the front foot in first than in second serves, while mean forces were higher (+17.2%, P < 0.05) under the lesser toes. Relative load was higher on the lateral forefoot (+20.4%, P < 0.05) but lower (-32.5%, P < 0.05) on the medial heel of the front foot with foot-up compared with foot-back stance. Using a foot-up stance, loading of the back foot was higher (+31.8%, P < 0.01) under the lateral mid-foot but lower (-29.9%, P < 0.01) under the medial forefoot. The type of serve and the stance style adopted have a significant effect on foot loading. Such findings might help improve mechanical efficiency of the serve.