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The Long Run Effects of R&D Place-based Policies: Evidence from Russian Science Cities
Full text linkWe study the long run effects of a unique historical place-based policies targeting R&D: the
creation of “Science Cities” in former Soviet Russia. The establishment of Science Cities and
the criteria for selecting their location were largely guided by political and military-strategic
considerations. We compare current demographic and economic characteristics of Science
Cities to those of appropriately matched localities that were similar to them at the time of
their establishment. We find that in the modern Russian economy, despite the massive cuts
of governmental support to R&D that followed the dissolution of the USSR, Science Cities
host more high-skilled workers and more developed R&D and ICT sectors; are the origin of
more international patents; and generally appear to be more productive and economically
developed. Within a spatial equilibrium framework, we interpret these findings as the result
of the interaction between persistence and agglomeration forces. Furthermore, we rule out
alternative explanations that have to do with the differential use of public resources, and
we find limited support for a case of equilibrium reversion. Finally, by analyzing firm-level
data we obtain evidence in favor of spillover effects with a wide spatial breadth
Ultrametricity increases the predictability of cultural dynamics
Full text linkA quantitative understanding of societies requires useful combinations of empirical data and mathematical models. Models of cultural dynamics aim at explaining the emergence of culturally homogeneous groups through social influence. Traditionally, the initial cultural traits of individuals are chosen uniformly at random, the emphasis being on characterizing the model outcomes that are independent of these (`annealed') initial conditions. Here, motivated by an increasing interest in forecasting social behavior in the real world, we reverse the point of view and focus on the effect of specific (`quenched') initial conditions, including those obtained from real data, on the final cultural state. We study the predictability, rigorously defined in an information-theoretic sense, of the \emphsocial content of the final cultural groups (i.e. who ends up in which group) from the knowledge of the initial cultural traits. We find that, as compared to random and shuffled initial conditions, the hierarchical ultrametric-like organization of empirical cultural states significantly increases the predictability of the final social content by largely confining cultural convergence within the lower levels of the hierarchy. Moreover, predictability correlates with the compatibility of short-term social coordination and long-term cultural diversity, a property that has been recently found to be strong and robust in empirical data. We also introduce a null model generating initial conditions that retain the ultrametric representation of real data. Using this ultrametric model, predictability is highly enhanced with respect to the random and shuffled cases, confirming the usefulness of the empirical hierarchical organization of culture for forecasting the outcome of social influence models
International regulation of historic buildings and nationalism: the role of UNESCO
No full textThis article focuses on the (ambiguous) relationships between nationalism and international regulation of historic buildings, namely, the activity of UNESCO in this field. It studies two different forms of UNESCO intervention: the creation of a list of world heritage sites of outstanding universal value, which includes several historic cities and buildings; and UNESCO Recommendations aimed at protecting historic urban landscape. The article shows that UNESCO seems to favour both political and cultural forms of nationalism and can significantly affect the nationalistic use of historic buildings and, more broadly, affect on the very idea of Nation and nationalism
The smile curve at the firm level: Where value is added along supply chains
No full textIn this paper, we investigate at the firm-level where value is added along supply chains on a sample of about 2 million firms in the European Union. In line with the hypothesis of a ‘smile curve’, we detect a non-linear U-shaped relationship between the value added content of a firm and its distance from final consumption. Tasks at the early and late stages of the supply chains generate higher value added, possibly due to a higher knowledge-intensity, after controlling for firm heterogeneity. Importantly, our work shows that it is possible to exploit firm-level databases for an empirical microfoundation of value generation, which is useful for understanding the possibly unequal benefits of participating in global value chains
Signaling with costly acquisition of signals
No full textIn this paper we investigate the consequences of introducing a cost to observe the signal in an otherwise standard signaling game. Beyond identifying equilibria, which we contrast with those of a standard signaling game, we study their robustness to two important classes of refinements: acting through restrictions on out-of-equilibrium beliefs and through trembles. Our results suggest that more prominence should be given to the pooling outcome on the minimum signal
Virtual Water Trade and Bilateral Conflicts
No full textIn light of growing water scarcity, virtual water, or the water embedded in key water-intensive commodities, has been an active area of debate among practitioners and academics alike. As of yet, however, there is no consensus on whether water scarcity affects conflict behavior and we still lack empirical research intending to account for the role of virtual water in affecting the odds of militarized disputes between states. Using quantitative methods and data on virtual water trade, we find that bilateral and multilateral trade openness reduce the probability of war between any given pair of country, which is consistent with the strategic role of this important commodity and the opportunity cost associated with the loss of trade gains. We also find that the substantive effect of virtual water trade is comparable to that of oil and gas, the archetypal natural resources, in determining interstate conflicts’ probability
A reaction-diffusion formulation to simulate EVA polymer degradation in environmental and accelerated ageing conditions
No full textAmong polymers used as encapsulant in photovoltaic (PV) modules, poly(ethylene-co-vinyl acetate), or EVA, is the most widely used, for its low cost and acceptable performances. When exposed to weather conditions, EVA undergoes degradation that affects overall PV performances. Durability prediction of EVA, and thus of the module, is a hot topic in PV process industry. To date, the literature lacks of long-term predictive computational models to study EVA aging. To fill this gap, a computational framework, based on the finite element method, is proposed to simulate chemical reactions and diffusion processes occurring in EVA. The developed computational framework is valid in either case of environmental or accelerated aging. The proposed framework enables the identification of a correspondence between induced degradation in accelerated tests and actual exposure in weathering conditions. The developed tool is useful for the prediction of the spatio-temporal evolution of the chemical species in EVA, affecting its optical properties. The obtained predictions, related to degradation kinetics and discoloration, show a very good correlation with experimental data taken from the literature, confirming the validity of the proposed formulation and computational approach. The framework has the potential to provide quantitative comparisons of degradation resulting from any environmental condition to that gained from accelerated aging tests, also providing a guideline to design new testing protocols tailored for specific climatic zones
Simulation of reaction-diffusion systems to assess EVA degradation in accelerated and environmental ageing conditions: a tool to design novel accelerated climate tests
No full textBlock Placement Strategies for Fault-Resilient Distributed Tuple Spaces: An Experimental Study - (Practical Experience Report)
No full textThe tuple space abstraction provides an easy-to-use programming paradigm
for distributed applications. Intuitively, it behaves like a distributed shared
memory, where applications write and read entries (tuples). When deployed over
a wide area network, the tuple space needs to efficiently cope with faults of links
and nodes. Erasure coding techniques are increasingly popular to deal with such
catastrophic events, in particular due to their storage efficiency with respect to
replication. When a client writes a tuple into the system, this is first striped into
k blocks and encoded into n > k blocks, in a fault-redundant manner. Then, any
k out of the n blocks are sufficient to reconstruct and read the tuple. This paper
presents several strategies to place those blocks across the set of nodes of a
wide area network, that all together form the tuple space. We present the performance
trade-offs of different placement strategies by means of simulations and a
Python implementation of a distributed tuple space. Our results reveal important
differences in the efficiency of the different strategies, for example in terms of
block fetching latency, and that having some knowledge of the underlying network
graph topology is highly beneficia
Synchronization of Reinforced Stochastic Processes with a Network-based Interaction
No full textRandomly evolving systems composed by elements which interact among each other have always been of great interest in several scientific fields. This work deals with the synchronization phenomenon, that could be roughly defined as the tendency of different components to adopt a common behavior. We continue the study of a model of interacting stochastic processes with reinforcement, that
recently has been introduced in [21]. Generally speaking, by reinforcement we mean any mechanism for which the probability that a given event occurs has an increasing dependence on the number of times that events of the same type occurred in the past. The particularity of systems of such interacting stochastic processes is that synchronization is induced along time by the reinforcement mechanism itself and does not require a large-scale limit. We focus on the relationship between the topology of the network of the interactions and the long-time synchronization phenomenon. After proving the almost sure synchronization, we provide some CLTs in the sense
of stable convergence that establish the convergence rates and the asymptotic distributions for both convergence to the common limit and synchronization. The obtained results lead to the construction of asymptotic confidence intervals for the limit random variable and of statistical tests to make inference on the topology of the network