Global renewable energy trade network: patterns and determinants

The renewable energy product trade is critically important to global economic prospects and its rapid development, making it a key issue in international economics of much interest to scholars. Previous studies have paid attention to bilateral trade, yet we still know little about the patterns of renewable energy product trade and its evolution from the whole industry perspective. Based on bilateral trade data, complex network, as well as ERGM and TERGM, we build global renewable energy trade networks (GRETNs) during 2000-2018 and explore the patterns and determinants. The results show that (1) the GRETNs expand during 2000-2018, characterized by a small-world, reciprocity, degree disassortative, and export volume heterogeneity. (2) The GRETNs form four communities, and the community patterns greatly fluctuate over time. (3) Economies in North America, Europe, and Asia play dominant roles, while the USA, Germany, and China are the cores of the GRETNs. (4) Endogenous structure of reciprocity, structural embeddedness, and out-degree popularity are essential parts of the evolving patterns of GRETNs. Most trade relationships are developed between economies located within the same continent, participating in APEC or WTO, or having similar areas. There is heterophily in GDP and per capita income, and Matthew effects in GDP, urbanization, and industrialization rate. Countries that share a common geographic border, language, religion, or currency, being former colonies of the same colonialists, and having signed regional trade agreements are more likely to trade in renewable energy products.

Unbalanced global vaccine product trade pattern: A network perspective

Mass vaccination is the most cost-effective intervention in response to public health events. Thus, equitable access to vaccine products is essential to ensure global human health. Based on the global vaccine product trade data from 2000 to 2018 and employing social network analysis, this paper explores the unbalanced pattern of global vaccine product trade and assesses the sensitivity interdependence between countries. Overall, the analysis shows that global vaccine product trade links have long been highly concentrated within developed countries in Europe and America. Nevertheless, with the rise of global and regional hub countries, the global vaccine product trade network has begun to evolve from a unipolar structure with the U.S. as the sole core to a multipolar structure with the U.S. and Western European countries as the core. Meanwhile, emerging countries, represented by China and India, are increasingly participating in the global vaccine product trade network and are beginning to play an important role. The formation of this multipolar pattern has provided countries in the Global South with more options for cooperation in the vaccine product trade and reduces the sensitivity interdependence of network periphery countries on core countries, which consequently reduces the global supply risk of vaccine products.

Research on the structural characteristics and influencing factors of global environmental services trade networks

The development of the environmental services trade is crucial to achieving climate goals and a green economic transition. Based on environmental services trade data from 2001 to 2019, this work uses the social network analysis (SNA) method to depict the structural features of global environmental services trade networks, empirically testing the influencing mechanism of network evolution based on the quadratic assignment procedure (QAP) model. The results indicate that the global environmental services trade is now in a rebound stable period. The market of the environmental services trade is becoming increasingly diversified, the accessibility and convenience of trade are constantly being enhanced, and there is an obvious core-edge structure in the network. Belgium, Italy, and the Netherlands are at the center of the global environmental services trade network; Greece, as the most prominent trade catch-up country, has gradually become an important "bridge" and "hub." Climate change, geographical distance, and population size are the key factors affecting the global trade network of environmental services; environmental regulation, economic distance, and green technology distance have no significant impact on the development of the global environmental services trade, and language difference is no longer an obstacle to the growth of this trade. The results indicate that countries should develop in-depth transnational trade cooperation in the field of environmental services and do so with a more open attitude. The government should give sufficient policy support to the import and export of environmental services, guaranteeing the development of the environmental services trade.

Most influential countries in the international medical device trade: Network-based analysis

Since the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, the international medical device trade has received extensive attention. To maintain the domestic supply of medical devices, some countries have sought multilateral trade cooperation or simply implemented export restrictions, which has exacerbated the instability and fragility of the global medical device market. It is crucial for government policymakers to identify the most influential countries in the international medical device trade and nip exports in the bud. However, few efforts have been made in previous studies to explore various countries' influence on the international medical device trade in light of their intricate trade relationships. To fill these research gaps, this study constructs a global medical device trade network (GMDTN) and explores the criticality of various countries from a network-based perspective. The evolution patterns and geographical distribution of influence among countries in the GMDTN are revealed. Details on the ways in which the influence of some crucial countries has formed are provided. The results show that the global medical device trade market is export oriented. The formation of some countries' strong influence may be due to their large number of trading partners or the deep dependence of some of those trading partners on that country (namely, breadth- or depth-based patterns). It is worth noting that the US has a dominant position in the international medical device trade in terms of both breadth and depth. In addition, some countries play a critical role as intermediate points in the influence formation process of other countries, although these countries are not critical direct trading partners. The findings of this study provide implications for policymakers seeking to understand the influence of countries on the international medical device trade and to proactively prepare responses to unexpected changes in this trade.

Emerging infectious diseases may spread across pig trade networks in Thailand once introduced: a network analysis approach

In Thailand, pork is one of the most consumed meats nationwide. Pig farming is hence an important business in the country. However, 95% of the farms were considered smallholders raising only 50 pigs or less. With limited budgets and resources, the biosecurity level in these farms is relatively low. Pig movements have been previously identified as a risk factor in the spread of infectious diseases. Therefore, the present study aimed to explicitly analyze the pig movement network structure and assess its vulnerability to the spread of emerging diseases in Thailand. We used official electronic records of nationwide pig movements throughout the year 2021 to construct a directed weighted one-mode network. Degree centrality, degree distribution, connected components, network community, and modularity were measured to explore the network architectures and properties. In this network, 484,483 pig movements were captured. In which, 379,948 (78.42%) were moved toward slaughterhouses and hence excluded from further analyses. From the remaining links, we suggested that the pig movement network in Thailand was vulnerable to the spread of emerging infectious diseases. Within the network, we found a strongly connected component (SCC) connecting 1044 subdistricts (38.6% of the nodes), a giant weakly connected component (GWCC) covering 98.2% of the nodes (2654/2704), and inter-regional communities with overall network modularity of 0.68. The disease may rapidly spread throughout the country. A better understanding of the nationwide pig movement networks is helpful in tailoring control interventions to cope with the newly emerged diseases once introduced.