1,721,135 research outputs found
Greening the mediterranean: North Africa and Middle East's pathways to environmental policy
No full textSecurity concerns and migration control have long characterised EU and European countries' relationships with the Southern flank of the Mediterranean, except for the 'deep democracy promotion' interlude after the 2010-2011 Arab uprisings, which vehemently called for a normative reorientation in the agenda-setting, albeit short-lived with hindsight. Against a backdrop of returning to business as usual, the environmental domain has nonetheless emerged, especially focusing on the energy sector and green transitions. While the EU's political and economic interest in greening its partnership with Mediterranean countries is no mystery, less is known about how its Southern neighbours stand regarding environmental policy. Thus, this chapter aims to offer an overview of North Africa and Middle East's 'greenisation' process and reluctance to it, as a combined effect of increasing domestic awareness which stems from Arab regimes' new ambitions, climate adaptation constraints and external pressure - namely, the EU's environmental pivot. The chapter reviews recent developments in national and regional cooperation initiatives in the so-called wider Mediterranean, reflecting on the new spaces for convergence and new sources of divergence that climate degradation foreshadows
Learning mechanisms within an Islamist party: Tunisia’s Ennahda Movement between domestic and regional balances
Full text linkThis article stresses the importance of learning in the transformation of an incumbent Islamist party within the context of polity re-configuration. Borrowing from the literature on diffusion and learning, it offers a case study of how Tunisia’s Ennahda Movement responded to the interplay of multi-level challenges. Main argument is that Ennahda has significantly re-tailored its positioning since the critical juncture of 2013, not only by taking the route of moderation once again, but also by exercising self-restraint under the impulse of external counter-examples. Based on process-tracing readings, the analysis contained herein demonstrates how key regional and domestic events have helped reshape the party’s political discourse and practices, designed to maximise the likelihood of its survival and progressive empowerment in a more markedly hostile environment. The paper thus empirically identifies three main strategies implemented by the party and reflecting learning on its part: readiness to negotiate, a reassuring attitude, and self-containment
The Tunisian Revolution and Democratic Transition: The Role of al-Nahdah, by Mohammad Dawood Sofi [Book review]
No full textThe pioneer country of the 2010/11 Arab uprisings, Tunisia, continues to be in the spotlight for its political developments. Even the initial enthusiasm for President Kaïs Saïed's constitutional coup, which capitalized on widespread disenchantment with a decade-long democratic transition that failed to deliver tangible economic benefits, seems to have diminished, if not completely vanished. The country's future appears uncertain against renewed skepticism, frustration, and anger. A timely contribution, Mohammad Dawood Sofi's latest book sets itself as a valuable compass to make sense of these developments and the political and social actors who were its main protagonists, first and foremost the self-described "Muslim-democratic" party, the Ennahdha Movement (from the Arabic al-Nahda, "the renaissance"
How Evolutionary Dynamics Affects Network Reciprocity in Prisoner's Dilemma
Full text linkCooperation lies at the foundations of human societies, yet why people cooperate remains a conundrum. The issue, known as network reciprocity, of whether population structure can foster cooperative behavior in social dilemmas has been addressed by many, but theoretical studies have yielded contradictory results so far—as the problem is very sensitive to how players adapt their strategy. However, recent experiments with the prisoner's dilemma game played on different networks and in a specific range of payoffs suggest that humans, at least for those experimental setups, do not consider neighbors' payoffs when making their decisions, and that the network structure does not influence the final outcome. In this work we carry out an extensive analysis of different evolutionary dynamics, taking into account most of the alternatives that have been proposed so far to implement players' strategy updating process. In this manner we show that the absence of network reciprocity is a general feature of the dynamics (among those we consider) that do not take neighbors' payoffs into account. Our results, together with experimental evidence, hint at how to properly model real people's behaviorThis work was supported by the Swiss Natural Science Foundation through grant PBFRP2_145872 and by Ministerio de Economía y Competitividad (Spain) through grant PRODIEVO.Publicad
Evolutionary Network Games: Equilibria from Imitation and Best Response Dynamics
Full text linkWe consider games of strategic substitutes and complements on networks and introduce two evolutionary dynamics in order to refine their multiplicity of equilibria. Within mean field, we find that for the best-shot game, taken as a representative example of strategic substitutes, replicator-like dynamics does not lead to Nash equilibria, whereas it leads to a unique equilibrium for complements, represented by a coordination game. On the other hand, when the dynamics becomes more cognitively demanding, predictions are always Nash equilibria: for the best-shot game we find a reduced set of equilibria with a definite value of the fraction of contributors, whereas, for the coordination game, symmetric equilibria arise only for low or high initial fractions of cooperators. We further extend our study by considering complex topologies through heterogeneous mean field and show that the nature of the selected equilibria does not change for the best-shot game. However, for coordination games, we reveal an important difference: on infinitely large scale-free networks, cooperative equilibria arise for any value of the incentive to cooperate. Our analytical results are confirmed by numerical simulations and open the question of whether there can be dynamics that consistently leads to stringent equilibria refinements for both classes of games
Removing spurious interactions in complex networks
Full text linkIdentifying and removing spurious links in complex networks is meaningful for many real applications and is crucial for improving the reliability of network data, which, in turn, can lead to a better understanding of the highly interconnected nature of various social, biological, and communication systems. In this paper, we study the features of different simple spurious link elimination methods, revealing that they may lead to the distortion of networks’ structural and dynamical properties. Accordingly, we propose a hybrid method that combines similarity-based index and edge-betweenness centrality. We show that our method can effectively eliminate the spurious interactions while leaving the network connected and preserving the network's functionalities
Model-based evaluation of scientific impact indicators
Full text linkUsing bibliometric data artificially generated through a model of citation dynamics calibrated on empirical data, we compare several indicators for the scientific impact of individual researchers. The use of such a controlled setup has the advantage of avoiding the biases present in real databases, and it allows us to assess which aspects of the model dynamics and which traits of individual researchers a particular indicator actually reflects. We find that the simple average citation count of the authored papers performs well in capturing the intrinsic scientific ability of researchers, regardless of the length of their career. On the other hand, when productivity complements ability in the evaluation process, the notorious h and g indices reveal their potential, yet their normalized variants do not always yield a fair comparison between researchers at different career stages. Notably, the use of logarithmic units for citation counts allows us to build simple indicators with performance equal to that of h and g. Our analysis may provide useful hints for a proper use of bibliometric indicators. Additionally, our framework can be extended by including other aspects of the scientific production process and citation dynamics, with the potential to become a standard tool for the assessment of impact metrics
Investigating the interplay between fundamentals of national research systems: performance, investments and international collaborations
Full text linkWe discuss, at the macro-level of nations, the contribution of research funding and rate of international collaboration to research performance, with important implications for the science of science policy. In particular, we cross-correlate suitable measures of these quantities with a scientometric-based assessment of scientific success, studying both the average performance of nations and their temporal dynamics in the space defined by these variables during the last decade. We find significant differences among nations in terms of efficiency in turning (financial) input into bibliometrically measurable output, and we confirm that growth of international collaboration positively correlate with scientific success, with significant benefits brought by EU integration policies. Various geo-cultural clusters of nations naturally emerge from our analysis. We critically discuss the possible factors that potentially determine the observed patterns
Grand canonical ensemble of weighted networks
Full text linkThe cornerstone of statistical mechanics of complex networks is the idea that the links, and not the nodes, are the effective particles of the system. Here, we formulate a mapping between weighted networks and lattice gases, making the conceptual step forward of interpreting weighted links as particles with a generalized coordinate. This leads to the definition of the grand canonical ensemble of weighted complex networks. We derive exact expressions for the partition function and thermodynamic quantities, both in the cases of global and local (i.e., node-specific) constraints on the density and mean energy of particles. We further show that, when modeling real cases of networks, the binary and weighted statistics of the ensemble can be disentangled, leading to a simplified framework for a range of practical applications
Estimating topological properties of weighted networks from limited information
Full text linkA problem typically encountered when studying complex systems is the limitedness of the information available on their topology, which hinders our understanding of their structure and of the dynamical processes taking place on them. A paramount example is provided by financial networks, whose data are privacy protected: Banks publicly disclose only their aggregate exposure towards other banks, keeping individual exposures towards each single bank secret. Yet, the estimation of systemic risk strongly depends on the detailed structure of the interbank network. The resulting challenge is that of using aggregate information to statistically reconstruct a network and correctly predict its higher-order properties. Standard approaches either generate unrealistically dense networks, or fail to reproduce the observed topology by assigning homogeneous link weights. Here, we develop a reconstruction method, based on statistical mechanics concepts, that makes use of the empirical link density in a highly nontrivial way. Technically, our approach consists in the preliminary estimation of node degrees from empirical node strengths and link density, followed by a maximum-entropy inference based on a combination of empirical strengths and estimated degrees. Our method is successfully tested on the international trade network and the interbank money market, and represents a valuable tool for gaining insights on privacy-protected or partially accessible systems
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