The Community Structure of the Global Corporate Network

We investigate the community structure of the global ownership network of transnational corporations. We find a pronounced organization in communities that cannot be explained by randomness. Despite the global character of this network, communities reflect first of all the geographical location of firms, while the industrial sector plays only a marginal role. We also analyze the network in which the nodes are the communities and the links are obtained by aggregating the links among firms belonging to pairs of communities. We analyze the network centrality of the top 50 communities and we provide the first quantitative assessment of the financial sector role in connecting the global economy

Spatial Localization in Manufacturing: A Cross-Country Analysis

This paper employs a homogenous firms database to investigate industry localization in European countries. More specifically, we compare, across industries and countries, the predictions of two of the most popular localization indices, i.e., the Ellison and Glaeser (1997) index and the Duranton and Overman (2005) index. We find that, independently from the index used, localization is a pervasive phenomenon in all countries studied, but the degree of localization is very uneven across industries in each country. Furthermore, we find that the two indices significantly diverge in predicting the intensity of the forces generating localization within each industry. Finally, we perform a cross-sectoral analysis of localized industries. We show that, in all countries, localized sectors are mainly ``traditional'' sectors (like jewelery, wine, and textiles) and sectors where scale economies are important. However, once one controls for countries' industrial structures science-based sectors turn out to be the most localized ones.Industry Localization; Manufacturing Industries; Localization Indices; Spatial Concentration; Spatial correlation; Cross-country studies

Spatial Localization in Manufacturing: A Cross-Country Analysis

This paper employs a homogenous firms' database to investigate industry localiza- tion in European countries. More specifically, we compare, across industries and countries, the predictions of two of the most popular localization indices, i.e., the Ellison and Glaeser index (Ellison and Glaeser, 1997) and the Duranton and Over- man index (Duranton and Overman, 2005). We find that, independently from the index used, localization is a pervasive phenomenon in all countries studied, but the degree of localization is very uneven across industries in each country. Furthermore, we find that the two indices significantly diverge in predicting the intensity of the forces generating localization within each industry. Finally, we perform a cross- sectoral analysis of localized industries. We show that, in all countries, localized sectors are mainly "traditional" sectors (like jewelery, wine, and textiles) and sec- tors where scale economies are important. However, once one controls for countries' industrial structures science-based sectors turn out to be the most localized ones.Industry Localization, Manufacturing Industries, Localization Indices, Spatial Concentration, Spatial correlation, Cross-country studies

Multi-scale analysis of the European airspace using network community detection

We show that the European airspace can be represented as a multi-scale traffic network whose nodes are airports, sectors, or navigation points and links are defined and weighted according to the traffic of flights between the nodes. By using a unique database of the air traffic in the European airspace, we investigate the architecture of these networks with a special emphasis on their community structure. We propose that unsupervised network community detection algorithms can be used to monitor the current use of the airspaces and improve it by guiding the design of new ones. Specifically, we compare the performance of three community detection algorithms, also by using a null model which takes into account the spatial distance between nodes, and we discuss their ability to find communities that could be used to define new control units of the airspace.Comment: 22 pages, 14 figure

The Network of Global Corporate Control

The structure of the control network of transnational corporations affects global market competition and financial stability. So far, only small national samples were studied and there was no appropriate methodology to assess control globally. We present the first investigation of the architecture of the international ownership network, along with the computation of the control held by each global player. We find that transnational corporations form a giant bow-tie structure and that a large portion of control flows to a small tightly-knit core of financial institutions. This core can be seen as an economic “super-entity” that raises new important issues both for researchers and policy makers

Statistical Regularities in ATM: network properties, trajectory deviations and delays

One of the key enabler to the productivity and efficiency shift foreseen by SESAR will be the business-trajectory concept. The path to a deep understanding of how this new concept impacts on the future SESAR Air Traffic Management scenario goes through a better understanding of the actual air traffic network, and this will be done in the present paper by analyzing traffic data within the framework of complex network analysis. In this paper we will consider flights trajectory data from the Data Demand Repository database. In a first investigation, we perform a network study of the air traffic infrastructure starting from the airports and then refining our analysis at the level of navigation points in order to understand what are the main features that may help explaining why some nodes of the network happen to be found in the same community, i.e. cluster. In a second investigation we perform a study at the level of flight trajectories with the aim of identify statistical regularities in the spatio-temporal deviations of flights between their planned and actual 4D trajectories

Ancient spring waters still emerging and accessible in the Roman Forum area. Chemical–physical and microbiological characterization

The presence of abundant surface and underground waters and, consequently, fertile and flat soils favored the birth and expansion of Rome. Before the construction of the first aqueduct, the “springs” were probably the only source of drinking water in Rome. At the same time, today, many of them are only scarce outcrops that, anyway, constitute an important heritage for their hydrogeological, archaeological, and monumental significance. In the present study, a multiparametric analytical approach is reported to highlight possible differences among the still emerging and accessible sources in the area of the Roman Forum and to exclude infiltrations from the water and/or sewage network. Temperature, conductivity, pH, dissolved oxygen, and redox potential were measured in situ, while the salt and bicarbonate content, the fixed residue, some UV-Vis indices, and the volatile organic compounds were determined in the laboratory. The microbiological water quality was evaluated by assaying Escherichia coli, intestinal Enterococci, and Salmonella, with the total bacterial count at 22 and 37°C. As expected, all samples are non-potable. Nevertheless, the comparison of data on standpipes close to the springs allowed us to exclude important infiltrations from the water network and the microbiological analysis of those from the sewer network

Muscle and adipose tissue morphology, insulin sensitivity and beta-cell function in diabetic and nondiabetic obese patients: effects of bariatric surgery

Obesity is characterized by insulin-resistance (IR), enhanced lipolysis, and ectopic, inflamed fat. We related the histology of subcutaneous (SAT), visceral fat (VAT), and skeletal muscle to the metabolic abnormalities, and tested their mutual changes after bariatric surgery in type 2 diabetic (T2D) and weight-matched non-diabetic (ND) patients. We measured IR (insulin clamp), lipolysis ((2)H5-glycerol infusion), ß-cell glucose-sensitivity (ß-GS, mathematical modeling), and VAT, SAT, and rectus abdominis histology (light and electron microscopy). Presurgery, SAT and VAT showed signs of fibrosis/necrosis, small mitochondria, free interstitial lipids, thickened capillary basement membrane. Compared to ND, T2D had impaired ß-GS, intracapillary neutrophils and higher intramyocellular fat, adipocyte area in VAT, crown-like structures (CLS) in VAT and SAT with rare structures (cyst-like) ~10-fold larger than CLS. Fat expansion was associated with enhanced lipolysis and IR. VAT histology and intramyocellular fat were related to impaired ß-GS. Postsurgery, IR and lipolysis improved in all, ß-GS improved in T2D. Muscle fat infiltration was reduced, adipocytes were smaller and richer in mitochondria, and CLS density in SAT was reduced. In conclusion, IR improves proportionally to weight loss but remains subnormal, whilst SAT and muscle changes disappear. In T2D postsurgery, some VAT pathology persists and beta-cell dysfunction improves but is not normalized