Characterising two-pathogen competition in spatially structured environments

Different pathogens spreading in the same host population often generate complex co-circulation dynamics because of the many possible interactions between the pathogens and the host immune system, the host life cycle, and the space structure of the population. Here we focus on the competition between two acute infections and we address the role of host mobility and cross-immunity in shaping possible dominance/co-dominance regimes. Host mobility is modelled as a network of traveling flows connecting nodes of a metapopulation, and the two-pathogen dynamics is simulated with a stochastic mechanistic approach. Results depict a complex scenario where, according to the relation among the epidemiological parameters of the two pathogens, mobility can either be non-influential for the competition dynamics or play a critical role in selecting the dominant pathogen. The characterisation of the parameter space can be explained in terms of the trade-off between pathogen's spreading velocity and its ability to diffuse in a sparse environment. Variations in the cross-immunity level induce a transition between presence and absence of competition. The present study disentangles the role of the relevant biological and ecological factors in the competition dynamics, and provides relevant insights into the spatial ecology of infectious diseases.Comment: 30 pages, 6 figures, 1 table. Final version accepted for publication in Scientific Report

International Scientist Mobility and the Locus of Technology Transfer

University technology transfer has attracted considerable attention in the literature with a focus on the institutions, the agents involved in technology commercialisation or the differentiation between formal and informal technology transfer mechanisms. There has, however, been little systematic research on how the mobility of university scientists influences their propensity to engage in technology transfer activities and, particularly, on how mobility influences the locus of such activities. This paper therefore analyses the link between university scientists' technology transfer activities and their international mobility patterns. We characterise scientist mobility along the two dimensions frequency' and intensity' resulting in an individual mobility pattern. We argue that the mobility pattern as well as the scientist's personal characteristics affects the likelihood whether a transfer of technology occurs to a firm in the scientist's home and/or host country. Based on a sample of more than 500 German university scientists, our results indicate that a substantial share of scientists engages in technology transfer both to the home as well as to the host country. There are, however, considerable differences regarding the factors influencing the locus of technology transfer. --scientist mobility,university technology transfer,internationalisation

Learning and Knowledge Diffusion in a Global Economy

I develop a dynamic general equilibrium model to understand how multinationals affect host countries through knowledge diffusion. Workers in the model learn from their managers and knowledge diffusion takes place through worker mobility. Unlike in a model without learning, I present a novel mechanism through which an integrated equilibrium represents a Pareto improvement for the host country. I go on to explore other dynamic consequences of integration. The entry of multinationals makes the lifetime earning profiles of host country workers steeper. At the same time, if agents learn fast enough, integration creates unequal opportunities, thereby widening inequality. The ex-workers of foreign multinationals also found new firms which are, on average, larger than the largest firms under autarky.Multinationals, knowledge diffusion, learning, worker mobility, Pareto improvement, spin-offs.

The mobility capacity of the manufacturing multinational enterprise: a framework and two case studies

In this paper, I try to develop a framework, which presents the factors influencing the mobility capacity of the manufacturing activity of a multinational enterprise (the difficulty/ease with which it can transfer its manufacturing activity from the initial host territory to another territory). I differentiate five factors: (1) the nature (generic vs. specific) of the territorial resources used by the multinational’s subsidiary; (2) market access offered by production in the host territory; (3) the durability and specificity of the fixed assets owned by the multinational enterprise in the host territory; (4) other barriers making exit out of the host territory difficult (redundancy costs, interrelatedness of the subsidiary’s activity with other units of the multinational enterprise, etc.); and (5) the availability of substitute plants by the multinational enterprise that can take over the production of the host territory’s subsidiary. Once the framework is presented, I use it to analyse the mobility potential of the activities of two multinational enterprises: a Taiwanese company (Nien Hsing Textile Co.) that was assembling trousers in Nicaragua (fieldwork in 1998 and 2007) and a Japanese company (Sony) that was assembling television sets and manufacturing cathode ray tubes in Wales (fieldwork in 2000-2001). The study shows the importance, in the short run, of the heaviness of the capital goods used in production as factor limiting mobility. In the long run, however, the degree of specificity (uniqueness) of the territorial resources employed by the multinational enterprise (qualified labour, specialised suppliers, etc.) is crucial. The study shows also the risk of the “no-upgrading trap†of inward manufacturing investment for peripheral host territories. Indeed, multinational enterprises that realise small profit margin activities, and in which labour costs occupy an important share in total production costs, will want to maintain their international mobility capacity to be able to respond swiftly to changes in the configuration of location advantages. Therefore, they will restrict their sunk investments (in fixed assets, in training, in collaborations with local suppliers, etc.) in the host territory. This strategy counters the local embeddedness of the subsidiary and limits its structural economic impact on the host territory.

Mobility Study for Named Data Networking in Wireless Access Networks

Information centric networking (ICN) proposes to redesign the Internet by replacing its host-centric design with information-centric design. Communication among entities is established at the naming level, with the receiver side (referred to as the Consumer) acting as the driving force behind content delivery, by interacting with the network through Interest message transmissions. One of the proposed advantages for ICN is its support for mobility, by de-coupling applications from transport semantics. However, so far, little research has been conducted to understand the interaction between ICN and mobility of consuming and producing applications, in protocols purely based on information-centric principles, particularly in the case of NDN. In this paper, we present our findings on the mobility-based performance of Named Data Networking (NDN) in wireless access networks. Through simulations, we show that the current NDN architecture is not efficient in handling mobility and architectural enhancements needs to be done to fully support mobility of Consumers and Producers.Comment: to appear in IEEE ICC 201

Inter-subnet localized mobility support for host identity protocol

Host identity protocol (HIP) has security support to enable secured mobility and multihoming, both of which are essential for future Internet applications. Compared to end host mobility and multihoming with HIP, existing HIP-based micro-mobility solutions have optimized handover performance by reducing location update delay. However, all these mobility solutions are client-based mobility solutions. We observe that another fundamental issue with end host mobility and multihoming extension for HIP and HIP-based micro-mobility solutions is that handover delay can be excessive unless the support for network-based micro-mobility is strengthened. In this study, we co-locate a new functional entity, subnet-rendezvous server, at the access routers to provide mobility to HIP host. We present the architectural elements of the framework and show through discussion and simulation results that our proposed scheme has achieved negligible handover latency and little packet loss

Learning, Knowledge Diffusion and the Gains from Globalization

We develop a dynamic, general equilibrium model to understand how multinationals affect host countries through knowledge diffusion. Workers learn from their managers and knowledge diffusion takes place through worker mobility. We identify two forces that determine wages : the labour demand effect and the learning effect. The former tends to raise wages while the latter tends to reduce it. We show that in a model without learning, an integrated steady-state equilibrium in which incumbent host country managers operate alongside multinationals, can never be a Pareto improvement for the host country. In contrast, we present a novel mechanism through which a Pareto improvement occurs in the presence of learning dynamics. We study how integration affects the life time earnings of agents and the degree of inequality in the host country, as well as, analyze the pattern of multinational activity. In the quantitative section of the paper, we calibrate our model to fit key moments from the U.S. wage distribution and quantify gains from integration. Our estimates suggest that learning produces welfare gains that range from 2% for middle-income countries to 43% for the low-income countries.Multinationals, knowledge di¤usion, learning, welfare gains, worker mobility