Why Do Some Places Succeed When Others Decline? A Social Interaction Model of Cluster Viability

One of the most convincing explanations papers generally provide concerning clusters in knowledge-based economies refers to the geographically bounded dimension of knowledge spillovers. Here we shall underline that location decision externalities precede local knowledge spillovers in the explanation of cluster aggregate efficiency, which thus requires us to focus on the sequential process of location and the nature of interdependences in location decision-making. To that end, we mean to associate cluster emergence with the formation of locational norms, and to study the critical parameters of their stability. These parameters relate to the type of decision externalities among more or less cognitively distant firms, which influences the weight and the resulting ambivalent role of knowledge spillovers at the aggregate level of clusters. We suggest two theoretical propositions which we test within a simple and general norm location dynamics modeling framework. We then proceed to discuss the results so obtained by comparing them with an emerging related literature based on the life cycle and viability of clustersclusters, location under decision externalities, cognitive distance, knowledge spillovers

Does the Internet make people happier ?

As people are spending more time online, it is important to evaluate the impact of Internet use on individual well-being. Internet use yields direct utility and economic returns (e.g. better job, higher productivity) that may increase life satisfaction. But the Internet might also have detrimental effects (addiction, social isolation, e.g.). This paper empirically examines the relation between Internet use and subjective well-being. Using Luxemburgish data from a European social survey, we find evidence that non users are less satisfied in their life than Internet users. This result holds when we control for socio-demographic characteristics, social capital, values and beliefs, and health and income. Moreover, the positive influence of Internet use is stronger for low income and young individuals. These findings suggest that public policy aiming to reduce the digital divide are socially desirableInternet, happiness, well-being, digital divide, social capital, social values

Does the Internet make people happier?

As people are spending more time online, it is important to evaluate the impact of Internet use on individual well-being. Internet use yields direct utility and economic returns (e.g. better job, higher productivity) that may increase life sa-tisfaction. But the Internet might also have detrimental effects (addiction, social isolation, e.g.). This paper empirically examines the relation between Internet use and subjective well-being. Using Luxemburgish data from a European so-cial survey, we find evidence that non users are less satisfied in their life than Internet users. This result holds when we control for socio-demographic charac-teristics, social capital, values and beliefs, and health and income. Moreover, the positive influence of Internet use is stronger for low income and young in-dividuals. These findings suggest that public policy aiming to reduce the digital divide are socially desirable..Internet; happiness; well-being; digital divide; social capital; social values

How do Clusters/Pipelines and Core/Periphery Structures Work Together in Knowledge Processes?

This paper contributes to the empirical identification of geographical and structural properties of innovative networks, focusing on the particular case of Global Navigation Satellite Systems (GNSS) at the European level. We show that knowledge bases of organizations and knowledge phases of the innovation process are the critical factors in determining the nature of the interplay between structural and geographical features of knowledge networks. Developing a database of R&D collaborative projects of the 5th and 6th European Framework Programs, we propose a methodology based on social network analysis. Its originality consists in starting from a bimodal network, in order to deduce two affiliation matrixes that allow us to study both the properties of the organization network and the properties of the project network. The results are discussed in the light of the mutual influence of the cognitive, structural and geographical dimensions on knowledge production and diffusion, and in the light of the knowledge drivers that give rise to the coexistence of a relational core-periphery structure with a geographical cluster and pipeline structure.Economic Geography, Knowledge networks, Social network analysis, EU Framework Programs, GNSS

Why some clusters succeed whereas others decline ? Modelling the ambivalent stability properties of clusters

The aim of this paper is to study the ambivalent properties of stabilities of clusters. We propose to enter the black box of the local knowledge externalities by focusing on the location decision externalities. In particular, we show that the nature of mimetic strategies in the convergence process of locational choices influence the dynamic stability of clusters. Thus, when uncertainty and search for legitimacy prevail on the need for coordination and the associated necessities of compatibility and technological convergence, the clusters are unstable, due to an excess of cognitive proximity and a risk of unintended spillovers. Nevertheless, this search for legitimacy, through the strategy which consists in following the locational choice of companies leader of a sector, can lead to the fast emergence of a cluster. But without relational proximity, its stability is not insured. These results are obtained following the formulation of some theoretical proposals on the links between location decision externalities and the resulting forms of socioeconomic proximities. This set of proposals is validated firstly by a model of simulation which makes it possible to test the properties of stability of aggregate outcomes of locational choices. Secondly, they are illustrated by a comparative empirical analysis of two main French clusters (Silicon Sentier and Sophia-Antipolis)..clusters, proximities, stability, location under decision externalities, Silicon Sentier, Sophia-Antipolis

Ω−\Omega^- and Ωˉ+\bar\Omega^+ production in Au+Au collisions at sNN\sqrt{s_{NN}} = 130 and 200 GeV

Mid-rapidity Omega and anti-Omega production in Au+Au collisions at RHIC is studied with the STAR experiment. We report preliminary results on yields and spectra at $\sqrt{s_{NN}}$ = 130 and 200 GeV. Production relative to negatively charged hadrons (h-) as well as thermal freeze-out and collective expansion are discussed.Comment: 4 pages, 5 figures, 1 table, Contribution to Quark Matter 2002, Nantes, France, July 200

Network structural properties for cluster long run dynamics. Evidence from collaborative R&D networks in the European mobile phone industry

In a recent literature, the structural properties of knowledge networks have been pointed out as a critical factor for cluster structural changes and long run dynamics. Mixing evolutionary economic geography and network-based approach of clusters, this contribution aims at capturing and discussing the particular influence of hierarchy (degree distribution) and assortativity (degree correlation) in the innovative capabilities of clusters along the industry life cycle. We test our propositions in the field of the mobile phone industry in Europe from 1988 to 2008. We use EPO PATSTAT and OECD REGPAT to capture cluster trends, and R&D relations from European Framework Programs to capture knowledge networks and their evolving structural properties. Our findings provide new insights to understand the organization of clusters over time in order to perform along the industry life cycl

The Ambivalent Role of Mimetic Behaviors in Proximity Dynamics: Evidences on the French “Silicon Sentier”

This articles examines the peculiar role of mimetic behaviors in co-location processes. We start showing that geographical proximity between agents and/or firms is not a sufficient nor necessary condition for the collective performance of clusters. Other types of socio-economic proximities characterize clusters, and our purpose is to show that, among the several ways to analyze the complex links between proximities and clusters, the theoretical outlook on the role played by mimetic interactions in co-location processes are certainly one of the most promising. Mimetic behaviors of location (in economics and sociology) are introduced in order to demonstrate that co-location processes can be the result of sequentiality, uncertainty, legitimacy and non market interactions, rather than full rational and isolated decisions and pure strategic market interactions. According to the type of mimetic behavior at work in the clustering process, the nature of socio-economic proximity can differ and have a strong influence of the “evolutionary stability” of clusters. All these theoretical considerations are illustrated through the emblematic French case of “Silicon Sentier”, cluster which has gathered together three hundred firms of the French net-economy (the famous “dotcom”) during the Internet bubble swelling.cluster, mimetic interactions, proximity, stability, Silicon Sentier

Estimations of Ωˉ+/Ω−\bar{\Omega}^+/\Omega^- at RHIC from a QGP Model with Diquarks

Assuming that axial-vector and scalar diquarks exist in the Quark-Gluon Plasma near the critical temporature $T_c$, baryons can be produced from quark-diquark interactions. In RHIC conditions ($\sqrt{s_{NN}} = 130GeV$ and $200GeV$), the ratio $\bar{\Omega}^+/\Omega^-$ may be larger than 1, based on the concept that QGP with diquarks would exist. This unusual result might be a helpful evidence for QGP existing in RHIC.Comment: 6 pages, 1 figure. accepted by J.Phys.

The STAR Silicon Strip Detector (SSD)

The STAR Silicon Strip Detector (SSD) completes the three layers of the Silicon Vertex Tracker (SVT) to make an inner tracking system located inside the Time Projection Chamber (TPC). This additional fourth layer provides two dimensional hit position and energy loss measurements for charged particles, improving the extrapolation of TPC tracks through SVT hits. To match the high multiplicity of central Au+Au collisions at RHIC the double sided silicon strip technology was chosen which makes the SSD a half million channels detector. Dedicated electronics have been designed for both readout and control. Also a novel technique of bonding, the Tape Automated Bonding (TAB), was used to fullfill the large number of bounds to be done. All aspects of the SSD are shortly described here and test performances of produced detection modules as well as simulated results on hit reconstruction are given.Comment: 11 pages, 8 figures, 1 tabl