Coalition formation in a contest game with three heterogeneous players

We analyze the incentives for cooperation of three players differing in their efficiency of effort in a contest game. We concentrate on the non-cooperative bargaining foundation of coalition formation, and therefore, we adopt a two-stage model. In the first stage, individuals form coalitions following a bargaining protocol similar to the one proposed by Gul (1989). Afterwards, coalitions play the contest game of Esteban and Ray (1999) within the resulting coalition structure of the first stage. We find that the grand coalition forms whenever the distribution of the bargaining power in the coalition formation game is equal to the distribution of the relative efficiency of effort. Finally, we use the case of equal bargaining power for all individuals to show that other types of coalition structures may be observed as well.

Anfíbios Anuros do Distrito Federal

The frogs of the Federal District of Brazil are listed and discussed as to habit, biology and ecology. The F. D is situated 22° 54' 24" S. & 43° 10' 21" W Gr. and comprises 1.356 km². Its topography includes sea-shore, maritime scrub, lagoons, plains and marsh, open slopes, forested mountains and great heads of rock. Three thousand feet of altitude are attained at two points. Fifty two different frogs occur in the F.D. Three fifths of them live in open country. Two fifths of these have never been found above the plains; the others range higher but mostly in open country. Their environment offers conditions suitable for average tadpoles and adults. these frogs are more or less unspecialized. There are six genera and thirty species. Two thirds of the latter belong to the type genera of the large neotropical families Bufonidae, Leptodactylidae and Hylidae. Only in the maritime scrub formation are conditions somewhat different. Water for average tadpoles is provided by the lagoons. The xerophytism of the vegetation is, however, so marked that bromeliads growing on the ground provide almost the only appropriate shelter for adult tree-frogs used to sleeping upright on the vegetation. One large Hylid genus lives entirely in them. It is casque-headed and phragmotic, shutting the lumen of the leaf-cup with head used as a plug. Another large Hylid genus shows a lesser degree of the same specialization. (Lutz A & Lutz B, 1939 II). One genus with two species is entirely saxicolous; it lives on wet ledges of rock at all phases of its life history. (B. Lutz 1948). The other two fifths of the frogs from F. D. are montane forest forms. Their environment offers numerous and varied biotopes and is near optimum for adults. There is,however, hardly any standing water available for larvae. These frogs are ecologically diversified. They also show a general trend towards spawning in the adult biotipe, which leads to delayed hatching, semi-aquatic and terrestrial larvae and direct development. (B Lutz, 1948). The author interprets the morphological specialization of the casque-headed Hylids and the biological specialization of the montane forest forms as adaptive. Casque-headedness and phragmosis increase protection against blood-suckers and predators. The humidity of the rain forest permits eggs, embryos and larvae to develop, unharmed, outside their usual, aquatic, environment.

When does universal peace prevail? Secession and group formation in rent seeking contests and policy conflicts

This paper analyzes secession and group formation in a general model of contest inspired by Esteban and Ray (1999). This model encompasses as special cases rent seeking contests and policy conflicts, where agents lobby over the choice of a policy in a one-dimensional policy space. We show that in both models the grand coalition is the efficient coalition structure and agents are always better off in the grand coalition than in a symmetric coalition structure. Individual agents (in the rent seeking contest) and extremists (in the policy conflict) only have an incentive to secede when they anticipate that their secession will not be followed by additional secessions. Incentives to secede are lower when agents cooperate inside groups. The grand coalition emerges as the unique subgame perfect equilibrium outcome of a sequential game of coalition formation in rent seeking contests.

Sequential formation of coalitions through bilateral agreements

We study a sequential protocol of endogenous coalition formation based on a process of bilateral agreements among the players. We apply the game to a Cournot environment with linear demand and constant average costs. We show that the final outcome of any Subgame Perfect Equilibrium of the game is the grand coalition, provided the initial number of firms is high enough and they are sufficiently patient.

Unemployment and wage formation in a growth model with public capital

We study the relation between public capital, employment and growth under different assumptions concerning wage formation. We show that public capital increases economic growth, and that, if there is wage inertia, employment positively depends on both economic growth and public capital.

On the regional impact of public capital formation in Spain

The objective of this paper is to investigate, in a methodologically consistent manner, the regional effects of public capital formation and the possible existence of regional spillover effects in Spain. The empirical results are based on VAR estimates at both the aggregate and regional levels using output, employment, and private capital, as well as different measures of public capital. Empirical results suggest that public capital affects output positively at the aggregate level as well as in all but one region. For most regions, the effects of public capital installed in the region itself are important but the spillover effects induced from public capital installed elsewhere are also very important. In fact, the spillover effects account for over half of the total effects of public capital formation in Spain. Furthermore, these spillover effects have a clear geographical pattern in that they tend to be more important in the peripheral regions of the country. We also find that relative to their share of the Spanish output, the biggest beneficiaries of public capital formation are the largest regions in the country. This suggests that public capital formation has contributed to concentration of output in these regions. Finally, in terms of the effects of public capital formation on the private inputs we find that both private capital and employment are affected positively at the aggregate level as well as for most of the regions. Nevertheless, the effects on private capital seem to be larger. Also, the spillover effects are very important for private capital but not for employment. This reflects a great degree of dynamism and mobility in the capital markets as opposed to the labor markets.

Spillover effects of public capital formation: evidence from the spanish regions

Maybe because of the inconclusive nature of the results on the impact of public capital on output at the regional level, the issue of the possible existence of the regional spillovers from public capital formation has received little attention. The objective of this paper is to provide evidence on the possible existence of such spillovers. We consider the case of Spain and its seventeen regions. Our methodological approach consists in estimating an aggregate VAR model for Spain as well as seventeen region-specific VAR models in which both capital installed in the region and capital installed outside the region are allowed to play a role in enhancing regional output. The estimation results can be summarized as follows. The aggregate effects of public capital formation in Spain are important. They cannot, however, be captured in their entirety by the direct effects in each region from public capital installed in the region itself. When for each region both the capital installed in the region and the capital installed outside the region are considered the total disaggregated effect from the seventeen regional models are very much in line with the aggregate results. Furthermore, the aggregate effect seems to be due in almost equal parts to the direct and spillover effects of public capital formation. Ultimately, this paper establishes the relevance of both capital installed in each region and spillover effects in the understanding of the regional decomposition of the aggregate effects of public capital formation. In doing so it opens the door to some tantalizing and potentially highly charged research issues in terms of the determination of the optimal location of public investment projects.

New business formation and employment growth: some evidence for the Spanish manufacturing industry

This paper explores the effects of new business formation on employment growth in Spanish manufacturing industries. New firms are believed to make an important contribution to economic growth but the extent of this contribution is unclear. We consider time lags of new firm formation as explanatory variables of employment change and identify how long the effect of new firm entries on employment lasts. Our main results show that the effects of new business formation are positive in the short term, negative in the medium term and positive in the long term, thus confirming the existence of indirect supply-side effects found in similar studies for other countries. Key words: regional growth, firm entry, time lags and Spanish economy. JEL classifications: L00, L60, R11, R12

Effects of a nursery CO2 enriched atmosphere on the germination and seedling morphology of two Mediterranean oaks with contrasting leaf habit

Abstract: The use of an enriched CO2 atmosphere in tree nurseries has been envisaged as a promising technique to increase productivity and to obtain seedlings with a higher root/shoot ratio, an essential trait to respond to water stress in Mediterranean-type ecosystems. In that framework, we have analyzed the effects of three levels of atmospheric CO2 concentration (350, 500 and 700 ppm) on the germination rate, growth and morphology of seedlings of two Mediterranean oaks used in reforestation programs: the evergreen Quercus ilex L. and the deciduous Quercus cerrioides Wilk. et Costa. CO2 enrichment increased the germination rate of Q. cerrioides (from 70±7 to 81±3 %) while it decreased that of Q. ilex (from 71±10 to 41±12 %). Seedlings of both species increased approximately 60% their total biomass in response to CO2 enrichment but at two different CO2 concentrations: 500 ppm for Q. cerrioides and 700 ppm for Q. ilex. This increase in seedlings biomass was entirely due to an augmentation of root biomass. Considering germination and biomass partitioning, an enriched CO2 atmosphere might not be appropriate for growing Mediterranean evergreen oaks, such as Q. ilex, since it reduces acorn germination and the only gains in root biomass occur at a high concentration (700 ppm). On the other hand, a moderate CO2 enrichment (500 ppm) appears as a promising nursery technique to stimulate the germination, growth and root/shoot ratio of deciduous oaks, such as Q. cerrioides. Resumen: El uso de una atmósfera enriquecida en CO2 durante la fase de vivero puede contribuir a aumentar la producción viverística, a la vez que ayudar a conseguir plántulas con una mayor relación biomasa subterránea/biomasa aérea, más adecuadas para hacer frente al severo estrés hídrico que generalmente limita el éxito de las repoblaciones en el clima Mediterráneo. En este estudio hemos analizado el efecto de tres niveles de abonado carbónico atmosférico (350, 500 y 750 ppm) en la germinación y morfología de plántulas de encina (Quercus ilex) y roble cerrioide (Quercus cerrioides). Una atmósfera enriquecida en CO2 incrementó la germinación de Q. cerrioides (de 70±7 a 81±3 %) mientras que disminuyó la de Q. ilex (de 71±10 a 41±12 %). Las plántulas de ambas especies incrementaron aproximadamente un 60% su biomasa en respuesta a una mayor concentración de CO2, aunque esta respuesta se produjo a diferentes dosis: 500 ppm en Q. cerrioides y 700 ppm en Q. ilex. El aumento en la biomasa total de las plántulas se debió enteramente a un mayor desarrollo de su sistema radical, Considerando tanto la germinación como los efectos sobre la relación biomasa subterránea/biomasa aérea, una atmósfera enriquecida en CO2 no parece ser un tratamiento adecuado para la producción en vivero de plántulas de Q.ilex, puesto que diminuye su germinación y solo aumenta su sistema radicular a dosis muy elevadas (700 ppm). Por el contrario, un aumento moderado en la concentración de CO2 (500 ppm) aparece como una técnica interesante para estimular el crecimiento y obtener plántulas de Q. cerrioides con un sistema radical más desarrollado.

Secondary effects of catalytic diesel particulate filters: copper-induced formation of PCDD/Fs.

Potential risks of a secondary formation of polychlorinated dibenzodioxins/furans (PCDD/Fs) were assessed for two cordierite-based, wall-through diesel particulate filters (DPFs) for which soot combustion was either catalyzed with an iron- or a copper-based fuel additive. A heavy duty diesel engine was used as test platform, applying the eight-stage ISO 8178/4 C1 cycle. DPF applications neither affected the engine performance, nor did they increase NO, NO2, CO, and CO2 emissions. The latter is a metric for fuel consumption. THC emissions decreased by about 40% when deploying DPFs. PCDD/F emissions, with a focus on tetra- to octachlorinated congeners, were compared under standard and worst case conditions (enhanced chlorine uptake). The iron-catalyzed DPF neither increased PCDD/F emissions, nor did it change the congener pattern, even when traces of chlorine became available. In case of copper, PCDD/F emissions increased by up to 3 orders of magnitude from 22 to 200 to 12 700 pg I-TEQ/L with fuels of < 2, 14, and 110 microg/g chlorine, respectively. Mainly lower chlorinated DD/Fs were formed. Based on these substantial effects on PCDD/F emissions, the copper-catalyzed DPF system was not approved for workplace applications, whereas the iron system fulfilled all the specifications of the Swiss procedures for DPF approval (VERT).

Granulomatous hypersensitivity to Schistosoma mansoni egg antigens in human Schistosomiasis: I. Granuloma formation and modulation around polyacrylamide antigen-conjugated beads

We have developed an in vitro model of granuloma formation for the purpose of studying the immunological components of delayed type hypersensitivity granuloma formation in patients infected with Schistosoma mansoni. Our data show that 1) granulomatous hypersensitivity can be studied by examining the cellular reactivity manifested as multiple cell layers surrounding the antigen conjugated beads; 2) this reactivity is a CD4 cell dependent, macrophage dependent, B cell independent response and 3) the in vitro granuloma response is antigenically specific for parasite egg antigens. Studies designed to investigate the immune regulation of granulomatous hypersensitivity using purified populations of either CD4 or CD8 T cells have demonstrated the complexity of cellular interactions in the suppression of granulomatous hypersensitivity. The anti-S. mansoni egg immune responses of individual patients with chronic intestinal schistosomiasis can be classified either as soluble egg antigen (SEA) hypersensitive with maximal granulomatous hypersensitivity or SEA suppressive with activation of the T cell suppressor pathway with effective SEA granuloma modulation. Our data suggest that T cell network interactions are active in the generation of effective granuloma modulation in chronic intestinal schistosomiasis patients.

Representation of motor habit in a sequence of repetitive reach and grasp movements performed by macaque monkeys: evidence for a contribution of the dorsolateral prefrontal cortex.

In the context of an autologous cell transplantation study, a unilateral biopsy of cortical tissue was surgically performed from the right dorsolateral prefrontal cortex (dlPFC) in two intact adult macaque monkeys (dlPFC lesioned group), together with the implantation of a chronic chamber providing access to the left motor cortex. Three other monkeys were subjected to the same chronic chamber implantation, but without dlPFC biopsy (control group). All monkeys were initially trained to perform sequential manual dexterity tasks, requiring precision grip. The motor performance and the prehension's sequence (temporal order to grasp pellets from different spatial locations) were analysed for each hand. Following the surgery, transient and moderate deficits of manual dexterity per se occurred in both groups, indicating that they were not due to the dlPFC lesion (most likely related to the recording chamber implantation and/or general anaesthesia/medication). In contrast, changes of motor habit were observed for the sequential order of grasping in the two monkeys with dlPFC lesion only. The changes were more prominent in the monkey subjected to the largest lesion, supporting the notion of a specific effect of the dlPFC lesion on the motor habit of the monkeys. These observations are reminiscent of previous studies using conditional tasks with delay that have proposed a specialization of the dlPFC for visuo-spatial working memory, except that this is in a different context of "free-will", non-conditional manual dexterity task, without a component of working memory.

Can a Lucas model with habit generate realistic conditional volatility in exchange rate returns?

In this paper, we attempt to give a theoretical underpinning to the well established empirical stylized fact that asset returns in general and the spot FOREX returns in particular display predictable volatility characteristics. Adopting Moore and Roche s habit persistence version of Lucas model we nd that both the innovation in the spot FOREX return and the FOREX return itself follow "ARCH" style processes. Using the impulse response functions (IRFs) we show that the baseline simulated FOREX series has "ARCH" properties in the quarterly frequency that match well the "ARCH" properties of the empirical monthly estimations in that when we scale the x-axis to synchronize the monthly and quarterly responses we find similar impulse responses to one unit shock in variance. The IRFs for the ARCH processes we estimate "look the same" with an approximately monotonic decreasing fashion. The Lucas two-country monetary model with habit can generate realistic conditional volatility in spot FOREX return.