Social Capital, Institutions and Collective Action Between Firms

This work is based on the hypothesis that explanation of collective action between firms requires partly different variables from that used in explaining collective action between individuals. In order to look at the problem of what determines collective action, a model has been built using alongside social capital, the historical tradition of collective action and the activism of institutional actors as explicative variables of associationism between firms. The empirical results confirm the theoretical hypotheses put forward in the first part of the paper. First, social capital, institutional activism and experience accumulation, all together, enhance the propensity to collective action between firms. Each variable plays a significant role in explaining inter-firm co-operation. Secondly, these variables, however, affect the behaviour of small firms while the large ones appear to follow a different pattern of conduct. Thirdly, the empirical findings seem also to suggest that social capital and institutional proactive initiative produce synergic effects on collective action. The two variables reinforce each other in their effects on co-operation. Finally, the positive correlation between social capital and institutional initiative emerging from the empirical results suggests that an increase in the endowment of social capital tends to rise the level of institutional activity and the other way round.social capital, economic institutions, firms co-operation

Innovazione e sviluppo locale. Concetti, esperienze, politiche

sviluppo economico, economia e politica dell'innovazione

La “New Economic Geography” e lo sviluppo locale

Questo lavoro è la versione preliminare del capitolo dedicato alla “New Economic Geography” (NEG) ed alle sue implicazioni per lo sviluppo locale del testo “Manuale di sviluppo locale” (a cura di G. Seravalli), attualmente in corso di stesura. Il lavoro studia innanzitutto il problema della localizzazione delle imprese produttrici di manufatti, distinguendo le forze che, nell’analisi della NEG, favoriscono la loro concentrazione o dispersione nel territorio. Fra gli elementi che determinano l’entità di tali forze un’attenzione particolare è dedicata all’esame dell’entità dei costi di trasporto, la cui evoluzione storica è, secondo la NEG, all’origine della nascita delle agglomerazioni industriali. L’ultima parte del lavoro analizza, infine, il ruolo delle risorse immobili, esaminandone le implicazioni per le scelte di localizzazione della produzione ed evidenziandone la rilevanza nell’avvio dei processi di sviluppo delle aree arretrate.economic geography, local development, transport costs, agglomeration

Institutions and co-ordination costs

Economic literature sees the existence of institutions as being justified by market failure. This paper attempts to develop a different hypothesis by linking institutions to the solution of co-ordination dilemmas. According to this line of thought, institutional action is not circumscribed to the supplying of ‘regulative resources’ able to lower uncertainty and limiting the risks of free riding. It includes rather the provision of a vast set of public goods characterised by high complementarity and marked constraints on the continuity of supply. In the production of such goods, the presence of multiplicity of equilibria and high costs of information born by individual agents in formulating a cooperative agreement often makes a decentralised decision-making process impracticable. On the other hand, as we try to show, a central authority (an institutional subject), assuming long term obligations and lowering co-ordination costs, can mitigate collective action problems in a wide range of circumstances

Capitale sociale, associazionismo economico e istituzioni: indicatori statistici di sintesi

In current debate, economic development is connected with relative social capital endowment, the diffusion of co-operative practices between firms and the role and efficiency of institutions. In this paper a factor analysis approach is used to provide synthetic indicators of these variables for Italian provinces. These indicators could be included in the set of analytical tools for the study of the relationship between economic development, public goods supply and collective action.social capital, economic institutions, firms co-operation, factor analysis

Optical pumping of charged excitons in unintentionally doped InAs quantum dots

As an alternative to commonly used electrical methods, we have investigated the optical pumping of charged exciton complexes addressing impurity related transitions with photons of the appropriate energy. Under these conditions, we demonstrate that the pumping fidelity can be very high while still maintaining a switching behavior between the different excitonic species. This mechanism has been investigated for single quantum dots of different size present in the same sample and compared with the direct injection of spectator electrons from nearby donors.Comment: 4 pages and 3 figures submitted to AP

Modelling of broadband light sources based on InAs / INxGA1-xAS metamorphic quantum dots

We propose a design for a semiconductor structure emitting broadband light in the infrared, based on InAs quantum dots (QDs) embedded into a metamorphic 4-step-graded InxGa1- xAs buffer with x = 0.10, 0.20, 0.30, 0.40. We developed a model to calculate metamorphic QD energy levels based on realistic QD parameters and on strain-dependent material properties: results of simulations were validated against experimental values. By simulating the broadband metamorphic structure, we demonstrated that its light emission can cover the whole 1.0 - 1.7 μm range with a bandwidth of 550 nm at 10K. The emission spectrum was then assessed under realistic electrical injection conditions, at room temperature, through device-level simulations based on a coupled drift-diffusion and QD dynamics model. As metamorphic QD devices have been already fabricated with satisfying performances we believe that this proposal is a viable option to realize broader band light-emitting devices such as superluminescent diodes

Broadband light sources based on InAs/InGaAs metamorphic quantum dots

We propose a design for a semiconductor structure emitting broadband light in the infrared, based on InAsquantum dots(QDs) embedded into a metamorphic step-graded InxGa1−xAs buffer. We developed a model to calculate the metamorphic QD energy levels based on the realistic QD parameters and on the strain-dependent material properties; we validated the results of simulations by comparison with the experimental values. On this basis, we designed a p-i-n heterostructure with a graded index profile toward the realization of an electrically pumped guided wave device. This has been done by adding layers where QDs are embedded in InxAlyGa1−x−yAs layers, to obtain a symmetric structure from a band profile point of view. To assess the room temperature electro-luminescenceemission spectrum under realistic electrical injection conditions, we performed device-level simulations based on a coupled drift-diffusion and QD rate equation model. On the basis of the device simulation results, we conclude that the present proposal is a viable option to realize broadband light-emitting devices