Mechanisms of reproductive isolation between an ant species of hybrid origin and one of its parents.

The establishment of new species by hybridization is difficult because it requires the development of reproductive isolation (RI) in sympatry to escape the homogenizing effects of gene flow from the parental species. Here we investigated the role of two pre- and two postzygotic mechanisms of RI in a system comprising two interdependent Pogonomyrmex harvester ant lineages (the H1 and H2 lineages) of hybrid origin and one of their parental species (P. rugosus). Similar to most other ants, P. rugosus is characterized by an environmental system of caste determination with female brood developing either into queens or workers depending on nongenetic factors. By contrast, there is a strong genetic component to caste determination in the H1 and H2 lineages because the developmental fate of female brood depends on the genetic origin of the parents, with interlineage eggs developing into workers and intralineage eggs developing into queens. The study of a mixed mating aggregation revealed strong differences in mating flight timing between P. rugosus and the two lineages as a first mechanism of RI. A second important prezygotic mechanism was assortative mating. Laboratory experiments also provided support for one of the two investigated mechanisms of postzygotic isolation. The majority of offspring produced from the few matings between P. rugosus and the lineages aborted at the egg stage. This hybrid inviability was under maternal influence, with hybrids produced by P. rugosus queens being always inviable whereas a small proportion of H2 lineage queens produced large numbers of adult hybrid offspring. Finally, we found no evidence that genetic caste determination acted as a second postzygotic mechanism reducing gene flow between P. rugosus and the H lineages. The few viable P. rugosus-H hybrids were not preferentially shunted into functionally sterile workers but developed into both workers and queens. Overall, these results reveal that the nearly complete (99.5%) RI between P. rugosus and the two hybrid lineages stems from the combination of two typical prezygotic mechanisms (mating time divergence and assortative mating) and one postzygotic mechanism (hybrid inviability).

Like milk or wine: Does firm performance improve with age?

Our empirical literature review shows that little is known about how firm performance changes with age, presumably because of the paucity of data on firm age. For Spanish manufacturing firms, we analyse the firm performance related to firm age between 1998 and 2006. We find evidence that firms improve with age, because ageing firms are observed to have steadily increasing levels of productivity, higher profits, larger size, lower debt ratios, and higher equity ratios. Furthermore, older firms are better able to convert sales growth into subsequent growth of profits and productivity. On the other hand, we also found evidence that firm performance deteriorates with age. Older firms have lower expected growth rates of sales, profits and productivity, they have lower profitability levels (when other variables such as size are controlled for), and also that they appear to be less capable to convert employment growth into growth of sales, profits and productivity. Keywords: firm age, firm growth, LAD, financial structure, vector autoregression JEL CODES: L25, L20

Ant brood function as life preservers during floods.

Social organisms can surmount many ecological challenges by working collectively. An impressive example of such collective behavior occurs when ants physically link together into floating 'rafts' to escape from flooded habitat. However, raft formation may represent a social dilemma, with some positions posing greater individual risks than others. Here, we investigate the position and function of different colony members, and the costs and benefits of this functional geometry in rafts of the floodplain-dwelling ant Formica selysi. By causing groups of ants to raft in the laboratory, we observe that workers are distributed throughout the raft, queens are always in the center, and 100% of brood items are placed on the base. Through a series of experiments, we show that workers and brood are extremely resistant to submersion. Both workers and brood exhibit high survival rates after they have rafted, suggesting that occupying the base of the raft is not as costly as expected. The placement of all brood on the base of one cohesive raft confers several benefits: it preserves colony integrity, takes advantage of brood buoyancy, and increases the proportion of workers that immediately recover after rafting.

Pork Value Chains: A Comparison of Catalonia, Spain and Manitoba, Canada

The purpose of this paper is to provide a comparative analysis of pork value chains in Catalonia, Spain and Manitoba, Canada. Intensive hog production models were implemented in Catalonia in the 1960s as a result of agriculture crises and fostered by feedstuffs factories. The expansion of the hog sector in Manitoba is more recent (in the 1990s) and brought about in large part by the opening of the Maple Leaf Meats processing plant in Brandon, Manitoba. This plant is capable of processing 90,000 hogs per week. Both hog production models ‐ the ‘older’ one in Catalonia (Spain) and the ‘newer’ in Manitoba‐ have been, until recently, examples of success. Inventories and production have been increasing substantially and both regions have proven to have great export potential. Recently, however, tensions have been developing with the hog production models of both regions, particularly as they relate to environmental concerns. The purpose of the paper is to compare the value chains with respect to their origins (e.g. supply a growing demand for pork, ensure farm profitability) and present states (e.g. environmental concerns, profitability). Keywords: pork value chain, hog farms, agri‐food studies. JEL: Q10, Q13, O57

Environmental Regulations in the Hog Farming Sector: A Comparison of Catalonia, Spain and Manitoba, Canada

This article examines the governance structures for managing the location and operation of Intensive Livestock Farming Operations (ILFOs). The article focuses on the hog sector and compares two very different jurisdictions: the Province of Manitoba, Canada and the Autonomous Community of Catalonia, Spain. Both are regions that have witnessed recent increases in hog production, including increasing spatial concentration of ILFOs and increasing size of those ILFOs. Policy has both fostered and sought to manage the increased production. Following a brief background description of restructuring, the changing legislative framework for Manitoba and Catalonia are described. Keywords: environmental regulations, hog farms, manure management, animal feeding operations. JEL: Q15, Q58, R52, O57

Productivity and human capital: a business-level analysis

This paper aims to analyse the impact of human capital on business productivity, focusing the analysis on the possible effect of the complementarity that exists between human capital and new production technologies, particularly advanced manufacturing technologies (AMTs) for the specific case of small and medium enterprises (SMEs) in Catalonia. Additionally, following the theory of skill-biased technological change, the paper analyses whether technological change produces bias exclusively in the skills required for managers, or whether the bias extends to the skills required of production staff. With this objective, we have compared the possible existence of complementarity between AMTs and the level of human capital for different occupational groups. The results confirm the complementary relationship between human capital and new production technologies. The results by occupational group confirm that to maximise the productivity of new technologies, skilled staff are needed both in management and production, with managers and professionals as well as skilled operatives playing a vital role. Keywords: human capital, process technologies, complementarity, business productivity. (JEL D24, J24, O30).

Contextualizing the impact of work organization on employee satisfaction

The paper assesses the relationship between the use of alternative workplace practices (AWP) and job satisfaction. Using a unique employeremployee data set with rich information on both firm and employee characteristics we test whether there is a positive impact of AWPs on job satisfaction (motivation hypothesis) or it is negative (intensification hypothesis). We expand a growing empirical literature focusing on small and medium size firms from a southern European area. Our results show an overall positive effect, depending on the specific practice considered. We also obtain some sort of time-dependence with the effects turning from negative to positive once the practice has been implemented for some time. Keywords: Job satisfaction, work organization, unobserved heterogeneity.

Innovation or Imitation? The effect of spillovers and competitive pressure on firms' R&D strategy choice

This article provides a theoretical and empirical analysis of a firm's optimal R&D strategy choice. In this paper a firm's R&D strategy is assumed to be endogenous and allowed to depend on both internal firms. characteristics and external factors. Firms choose between two strategies, either they engage in R&D or abstain from own R&D and imitate the outcomes of innovators. In the theoretical model this yields three types of equilibria in which either all firms innovate, some firms innovate and others imitate, or no firm innovates. Firms'equilibrium strategies crucially depend on external factors. We find that the efficiency of intellectual property rights protection positively affects firms'incentives to engage in R&D, while competitive pressure has a negative effect. In addition, smaller firms are found to be more likely to become imitators when the product is homogeneous and the level of spillovers is high. These results are supported by empirical evidence for German .rms from manufacturing and services sectors. Regarding social welfare our results indicate that strengthening intellectual property protection can have an ambiguous effect. In markets characterized by a high rate of innovation a reduction of intellectual property rights protection can discourage innovative performance substantially. However, a reduction of patent protection can also increase social welfare because it may induce imitation. This indicates that policy issues such as the optimal length and breadth of patent protection cannot be resolved without taking into account specific market and firm characteristics. Journal of Economic Literature Classification Numbers: C35, D43, L13, L22, O31. Keywords: Innovation; imitation; spillovers; product differentiation; market competition; intellectual property rights protection.

Designing the Optimal Conservativeness of the Central Bank

In this paper we propose a new measure of the degree of conservativeness of an inde- pendent central bank and we derive the optimal value from the social welfare perspective. We show that the mere appointment of an independent central bank is not enough to achieve lower inflation, which may explain the mixed results found between central bank independence and inflation in the empirical literature. Further, the optimal central bank should not be too conservative. For instance, we will show that in some circumstances it will be optimal that the central bank is less conservative than society in the Rogoff sense. JEL classification: E58, E63. Keywords: Central bank; Conservativeness; Independence.

Air services on thin routes: Regional versus low-cost airlines

An examination of the impact in the US and EU markets of two major innovations in the provision of air services on thin routes - regional jet technology and the low-cost business model - reveals significant differences. In the US, regional airlines monopolize a high proportion of thin routes, whereas low-cost carriers are dominant on these routes in Europe. Our results have different implications for business and leisure travelers, given that regional services provide a higher frequency of flights (at the expense of higher fares), while low-cost services offer lower fares (at the expense of lower flight frequencies). Keywords: air transportation; regional jet technology; low-cost business model; thin markets. JEL Classification Numbers: L13; L2; L93.

Aerotropolis: an aviation-linked space

This paper examines the conditions allowing the formation of aeropolitan areas as large industrial areas with a high concentration of commercial activities in the proximity of selected airports. We assume that firms deliver their production by plane and land competition takes place among service operators, firms and farmers. Service operators supply facilities that firms can absorb. Our framework identifies a unique land equilibrium characterized by the spatial sequence Airport - Industrial park - Rural area (A-I-R). Aerotropolis-type configurations are associated with the level of transport costs and the degree of intensity of facilities. Keywords: aerotropolis; facilities; bid-rent function. JEL Classification Numbers: L29; L90; R14.

A Folk Theorem for Games when Frequent Monitoring Decreases Noise

This paper studies frequent monitoring in an infinitely repeated game with imperfect public information and discounting, where players observe the state of a continuous time Brownian process at moments in time of length _. It shows that a limit folk theorem can be achieved with imperfect public monitoring when players monitor each other at the highest frequency, i.e., _. The approach assumes that the expected joint output depends exclusively on the action profile simultaneously and privately decided by the players at the beginning of each period of the game, but not on _. The strong decreasing effect on the expected immediate gains from deviation when the interval between actions shrinks, and the associated increase precision of the public signals, make the result possible in the limit. JEL: C72/73, D82, L20. KEYWORDS: Repeated Games, Frequent Monitoring, Public Monitoring, Brownian Motion.

Public Monitoring with Uncertainty in the Time Repetitions

This paper study repeated games where the time repetitions of the stage game are not known or controlled by the players. We call this feature random monitoring. Kawamori's (2004) shows that perfect random monitoring is always better than the canonical case. Surprisingly, when the monitoring is public, the result is less clear-cut and does not generalize in a straightforward way. Unless the public signals are sufficiently informative about player's actions and/or players are patient enough. In addition to a discount effect, that tends to consistently favor the provision of incentives, we found an information effect, associated with the time uncertainty on the distribution of public signals. Whether payoff improvements are or not possible, depends crucially on the direction and strength of these effects. JEL: C73, D82, D86. KEYWORDS: Repeated Games, Frequent Monitoring, Random Public Monitoring, Moral Hazard, Stochastic Processes.

High Growth Firms and Innovation: an empirical analysis for Spanish firms

This paper analyzes the effect of firms’ innovation activities on their growth performance. In particular, we observe how important innovation is for high-growth firms (HGFs) for an extensive sample of Spanish manufacturing and services firms. The panel data used comprises diverse waves of Spanish CIS over the the period 2004-2008. First, a probit analysis determines whether innovation affects the probability of being a high-growth firm. And second, a quantile regression technique is applied to explore the determinants and characteristics of specific groups of firms (manufacturing versus service firms and high-tech versus low-tech firms). It is revealed that R&D plays a significant role in the probability of becoming a HGF. Investment in internal and external R&D per employee has a positive impact on firm growth (although internal R&D presents a significant impact in the last quantiles, external R&D is significant up to the median). Furthermore, we show evidence that there is a positive impact of employment (sales) growth on the sales (employment) growth. Keywords: high-growth firms, firm growth, innovation activity JEL Classifications: L11, L25, O30

Determinants of high-growth firms:why do some countries have more high-growth firms than others?

High-growth firms have been shown to be a key factor for economic growth and structural change. This paper analyses the determinants of the number of high-growth firms in a country for 17 OECD countries between 1999 and 2005, using the Amadeus data set, the GEM data set, and others. The first contribution of this paper is that it is – as far as we know – the first empirical analysis of high-growth firms at the country level on the basis of actual measured growth. Second, we find indicative empirical evidence for three driving forces of high growth, viz. entrepreneurship, institutional settings, and opportunities for growth, all in accordance with theory and empirical findings in related fields of research. Third, the paper gives a tentative explanation of the differences in the average percentage of high-growth firms between countries. Finally, the paper gives some clues for policy makers how to promote high-growth firms. Keywords: high-growth firms, fast growing firms, entrepreneurship, institutional obstacles, opportunities for growth