138 research outputs found

    Social Capital, Institutions and Collective Action Between Firms

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    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

    Institutions and co-ordination costs

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    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

    T Dependence of the Mechanical Properties on the Microstructural Parameters of WC-Co

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    Abstract The effect of binder content and WC grain size on the mechanical properties is widely investigated in literature. An increase in binder amount and WC grain size leads to a decrease in hardness and an increase in fracture toughness. Actually, these correlations are related to the influence of binder content and WC grain size through the contiguity and mean binder free path, which are the microstructural parameters that affect the mechanical properties. The aim of this study is to verify the dependence of the two microstructural parameters that govern the WCCo mechanical behaviour, namely the contiguity and mean binder free path, on the mechanical properties of an extended range of WC-Co samples, which differ in terms of Co content and tungsten carbide grain size

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

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    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

    Nanoscale phase separation in the iron chalcogenide superconductor K0.8Fe1.6Se2 as seen via scanning nanofocused x-ray diffraction

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    Advanced synchrotron radiation focusing down to a size of 300 nm has been used to visualize nanoscale phase separation in the K0.8Fe1.6Se2 superconducting system using scanning nanofocus single-crystal X-ray diffraction. The results show an intrinsic phase separation in K0.8Fe1.6Se2 single crystals at T< 520 K, revealing coexistence of i) a magnetic phase characterized by an expanded lattice with superstructures due to Fe vacancy ordering and ii) a non-magnetic phase with an in-plane compressed lattice. The spatial distribution of the two phases at 300 K shows a frustrated or arrested nature of the phase separation. The space-resolved imaging of the phase separation permitted us to provide a direct evidence of nanophase domains smaller than 300 nm and different micrometer-sized regions with percolating magnetic or nonmagnetic domains forming a multiscale complex network of the two phases.Comment: 5 pages, 4 figure

    Inhomogeneity of charge density wave order and quenched disorder in a high Tc superconductor

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    It has recently been established that the high temperature (high-Tc) superconducting state coexists with short-range charge-density-wave order and quenched disorder arising from dopants and strain. This complex, multiscale phase separation invites the development of theories of high temperature superconductivity that include complexity. The nature of the spatial interplay between charge and dopant order that provides a basis for nanoscale phase separation remains a key open question, because experiments have yet to probe the unknown spatial distribution at both the nanoscale and mescoscale (between atomic and macroscopic scale). Here we report micro X-ray diffraction imaging of the spatial distribution of both the charge-density-wave puddles (domains with only a few wavelengths) and quenched disorder in HgBa2CuO4+y, the single layer cuprate with the highest Tc, 95 kelvin. We found that the charge-density-wave puddles, like the steam bubbles in boiling water, have a fat-tailed size distribution that is typical of self-organization near a critical point. However, the quenched disorder, which arises from oxygen interstitials, has a distribution that is contrary to the usual assumed random, uncorrelated distribution. The interstitials-oxygen-rich domains are spatially anti-correlated with the charge-density-wave domains, leading to a complex emergent geometry of the spatial landscape for superconductivity.Comment: 11 pages, 3 figure

    Anionic glycolipids related to glucuronosyldiacylglycerol inhibit protein kinase Akt

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    New glucuronosyldiacylglycerol (GlcADG) analogues based on a 2-O-\u3b2-D-glucopyranosyl-sn-glycerol scaffold and carrying one or two acyl chains of different lengths have been synthesized as phosphatidylinositol 3-phosphate (PI3P) mimics targeting the protein kinase Akt. Akt inhibitory effect of prepared compounds, was assayed using an in vitro kinase assay. The antiproliferative activity of the compounds was tested in the human ovarian carcinoma IGROV-1 cell line in which we found that two of them could inhibit proliferation, in keeping with the target inhibitory effect

    The effect of internal pressure on the tetragonal to monoclinic structural phase transition in ReOFeAs: the case of NdOFeAs

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    We report the temperature dependent x-ray powder diffraction of the quaternary compound NdOFeAs (also called NdFeAsO) in the range between 300 K and 95 K. We have detected the structural phase transition from the tetragonal phase, with P4/nmm space group, to the orthorhombic or monoclinic phase, with Cmma or P112/a1 (or P2/c) space group, over a broad temperature range from 150 K to 120 K, centered at T0 ~137 K. Therefore the temperature of this structural phase transition is strongly reduced, by about ~30K, by increasing the internal chemical pressure going from LaOFeAs to NdOFeAs. In contrast the superconducting critical temperature increases from 27 K to 51 K going from LaOFeAs to NdOFeAs doped samples. This result shows that the normal striped orthorhombic Cmma phase competes with the superconducting tetragonal phase. Therefore by controlling the internal chemical pressure in new materials it should be possible to push toward zero the critical temperature T0 of the structural phase transition, giving the striped phase, in order to get superconductors with higher Tc.Comment: 9 pages, 3 figure
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