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This paper analyzes the role played by the cognitive dimension of social capital on knowledge acquisition in clustered firms. We have applied a structural model to an empirical survey of the Spanish footwear industry. Findings detect a significant indirect effect of the district membership on knowledge acquisition through cognitive social capital development. In contrast with the assumption of direct and free access to common knowledge in territorial agglomerations, findings suggested that knowledge access depends on the capacity of the firms to share visions, goals, values, and culture with other actors in the local neighborhood. The social capital perspective provides a solid base to explain heterogeneity among firm members in the industrial district in order to access common knowledge and capacities. Findings suggested that institutions involved in a district must favour efforts to boost the collective representation as well as common goals and vision.  相似文献   
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In the northwestern Mediterranean, most fish species reproduce in early summer and fewer in the autumn mixing period. This study analyses and compares larval fish assemblages (LFA) in both seasons, and is the first attempt to characterize LFA structure for the autumn period. We analyze horizontal and vertical distribution of fish larvae and the micro- and mesozooplankton biomass and abundance of the main zooplankton groups. The oceanographic situation was analyzed through the study of data from CTD, Nν-Shuttle and ADCP surveys. LFA were determined by ordination analyses based on larval abundance, and the relationships between larval assemblages and environmental variables were investigated through canonical correspondence analysis. The importance of some hydrographic variables (temperature, salinity and stability of the water column), current fields (along-shelf and across-shelf transport) and the abundance of zooplankton are discussed as important factors shaping the structure of larval assemblages. In early summer, LFA were mainly structured by a combination of bathymetry and trophic components, although sea surface temperature also played a role in shaping the horizontal larval distributions. In autumn, trophic variables were the main factors influencing the shelf-dwelling species assemblage. Larvae of oceanic species, on the other hand, were not related to trophic variables but were more affected by current fields.  相似文献   
3.
We estimated patchiness for different life stages (egg, larvae and juveniles) of European hake (Merluccius merluccius) from two ichthyoplankton surveys (September and November 1999) and four bottom‐trawl surveys (November 1998, February, June and September 1999). Lloyd's patchiness P = 1 + 1/k, where k is the dispersion parameter of the negative binomial distribution, was calculated. Juveniles showed lower indices of patchiness than early ontogenetic stages. In juveniles, patchiness was highest for smaller size classes (3.5–5 cm TL) settling to their near‐bottom habitat and was very low for those larger than 5 cm up to the 30–35 cm size class (approximately 3 yr of age, 50% mature individuals). Patchiness of settling juveniles was especially high in the June and September surveys, coinciding with peak recruitment to the bottom. Both eggs and yolk sac larvae showed patchiness values <10, increasing in flexion stage larvae from 12 to 20. This pattern is different to that observed in other studies for pelagic species, where patchiness of early‐stage eggs is very high, but coincides with results obtained for other demersal species with pelagic eggs. Factors that may explain these patterns are discussed in light of oceanographic conditions, adult distribution and larval ontogenesis.  相似文献   
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A series of works have analysed differential behaviour in terms of productive efficiency between companies inside a hypothetical industrial district and those outside the district. This objective has been addressed using measures of technical efficiency. The results obtained provide valuable information for quantifying the district effect at a given moment in time. However, constant changes in the market and business behaviour mean that it is worthwhile studying the business district effect from a dynamic point of view. In this study, we provide this new vision through the use of Malmquist productivity indices. This methodology enables us to analyse possible differential evolutions by comparing the productive efficiency of companies inside and outside a district over a period of time. An empirical application has been made on a set of small and medium‐sized Spanish ceramic producers during the period of economic expansion between 1996 and 2007.  相似文献   
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