Evolution of controllability in interbank networks

The Statistical Physics of Complex Networks has recently provided new theoretical tools for policy makers. Here we extend the notion of network controllability to detect the financial institutions, i.e. the drivers, that are most crucial to the functioning of an interbank market. The system we investigate is a paradigmatic case study for complex networks since it undergoes dramatic structural changes over time and links among nodes can be observed at several time scales. We find a scale-free decay of the fraction of drivers with increasing time resolution, implying that policies have to be adjusted to the time scales in order to be effective. Moreover, drivers are often not the most highly connected “hub” institutions, nor the largest lenders, contrary to the results of other studies. Our findings contribute quantitative indicators which can support regulators in developing more effective supervision and intervention policies

Portfolio diversification, differentiation and the robustness of holdings networks

Abstract Networks of portfolio holdings exemplify how interdependence both between the agents and their assets can be a source of systemic vulnerability. We study a real-world holdings network and compare it with various alternative scenarios from randomization and rebalancing of the original investments. Scenarios generation relies on algorithms that satisfy the global constraints imposed by the numbers of outstanding shares in the market. We consider fixed-diversification models and diversification-maximizing replicas too. We extensively analyze the interplay between portfolio diversification and differentiation, and how the outreach of exogenous shocks depends on these factors as well as on the type of shock and the size of the network with respect to the market. We find that real portfolios are poorly diversified but highly similar, that portfolio similarity correlates with systemic fragility and that rebalancing can come with an increased similarity depending on the initial network configuration. We show that a large diversification gain is achieved through rebalancing but, noteworthy, that makes the network vulnerable in front of unselective shocks. Also, while the network is riskier in the presence of targeted shocks, it is safer than its random counterparts when it is stressed by widespread price downturns

Systemic risk from investment similarities

Network theory proved recently to be useful in the quantification of many properties of financial systems. The analysis of the structure of investment portfolios is a major application since their eventual correlation and overlap impact the actual risk by individual investors. We investigate the bipartite network of US mutual fund portfolios and their assets. We follow its evolution during the Global Financial Crisis and study the diversification, as understood in modern portfolio theory, and the similarity of the investments of different funds. We show that, on average, portfolios have become more diversified and less similar during the crisis. However, we also find that large overlap is far more likely than expected from benchmark models of random allocation of investments. This indicates the existence of strong correlations between fund investment strategies. We exploit a deliberately simplified model of shock propagation to identify a systemic risk component stemming from the similarity of portfolios. The network is still partially vulnerable after the crisis because of this effect, despite the increase in the diversification of multi asset portfolios. Diversification and similarity should be taken into account jointly to properly assess systemic risk

The Network of U.S. Mutual Fund Investments: Diversification, Similarity and Fragility throughout the Global Financial Crisis

Network theory proved recently to be useful in the quantification of many properties of financial systems. The analysis of the structure of investment portfolios is a major application since their eventual correlation and overlap impact the actual risk diversification by individual investors. We nvestigate the bipartite network of US mutual fund portfolios and their assets. We follow its evolution during the Global Financial Crisis and analyse the interplay between diversification, as understood in classical portfolio theory, and similarity of the investments of different funds. We show that, on average, portfolios have become more diversified and less similar during the crisis. However, we also find that large overlap is far more likely than expected from models of random allocation of investments. This indicates the existence of strong correlations between fund portfolio strategies. We introduce a simplified model of propagation of financial shocks, that we exploit to show that a systemic risk component origins from the similarity of portfolios. The network is still vulnerable after crisis because of this effect, despite the increase in the diversification of portfolios. Our results indicate that diversification may even increase systemic risk when funds diversify in the same way. Diversification and similarity can play antagonistic roles and the trade-off between the two should be taken into account to properly assess systemic risk

Massive upper gastrointestinal bleeding from a pancreatic pseudocyst rupture: a case report

INTRODUCTION: Bleeding from pancreatic pseudocyst's rupture into adjacent organs is a rare, but potentially fatal, complication of chronic pancreatitis requiring quick management. Timing of the rupture is unpredictable; early diagnosis and correct management is essential in preventing the bleeding. CASE PRESENTATION: We describe the case of a 53 years old male patient successfully treated with emergency surgery for massive hematemesis due to a rupture of a bleeding pseudocyst into the stomach. Patient underwent emergency laparotomy and suture of the bleeding vessel. At 5 years follow-up patient is in healthy condition. CONCLUSION: This case shows to surgeons that pancreatic pseudocyst cannot be managed strictly with one rule and prompt surgical treatment is mandatory in case of haemodinamic instability

A Retrospective Study One-Year Survey from COVID-19: Three Waves and Three Patterns in Italy

Background: Since December 2019 an unprecedented coronavirus pandemic (COVID-19) in Italy and in all the world, has been spreading. This study is a retrospective overview of Italian popul

Molecular pathogenesis of craniopharyngioma: switching from a surgical approach to a biological one

Craniopharyngioma has long been considered a benign tumor because of its pathological aspect. This primordial view of craniopharyngioma fit with the primitive treatment attempts based on blind resection of the tumor each time it recurred. The limits of this management strategy were proven early by the high morbidity related to the resection and recurrence risk despite radical lesion removal. Nowadays, craniopharyngioma must be considered a complex molecular disease, and a detailed explanation of the mechanisms underlying its aggressive biological and clinical behavior, despite some benign pathological features, would be the first step toward defining the best management of craniopharyngioma. Indeed, advances in the knowledge of the molecular mechanisms at the base of craniopharyngioma oncogenesis will lead to comprehension of the critical checkpoints involved in neoplastic transformation. The final research target will be the definition of new biological agents able to reverse the neoplastic process by acting on these critical checkpoints. This biological approach will lead to a refined therapy combining higher efficacy and safety with lower morbidity. In this paper the authors reveal state-of-the-art comprehension of the molecular biology of craniopharyngioma and the consequent therapeutic implications

Consensus communication strategies to improve doctor-patient relationship in paediatric severe asthma

Background: Asthma is a chronic inflammatory disease that is very common among youth worldwide. The burden of this illness is very high not only considering financial costs but also on emotional and social functioning. Guidelines and many researches recommend to develop a good communication between physicians and children/caregiver and their parents. Nevertheless, a previous Italian project showed some criticalities in paediatric severe asthma management. The consensus gathered together experts in paediatric asthma management, experts in narrative medicine and patient associations with the aim of identify simple recommendation to improve communication strategies. Methods: Participants to the consensus received the results of the project and a selection of narratives two weeks before the meeting. The meeting was structured in plenary session and in three working groups discussing respectively about communication strategies with children, adolescents and parents. The task of each working group was to identify the most effective (DO) and least effective practices (DON' T) for 5 phases of the visit: welcome, comprehension of the context, emotions management, duration and end of the visit and endurance of the relationship. Results: Participants agreed that good relationships translate into positive outcomes and reached consensus on communication strategies to implement in the different phase of relationships. Conclusions: The future challenges identified by the participants are the dissemination of this Consensus document and the implementation of effective communication strategies to improve the management of pediatric asthma

A multi-level geographical study of Italian political elections from Twitter Data

In this paper we present an analysis of the behavior of Italian Twitter users during national political elections. We monitor the volumes of the tweets related to the leaders of the various political parties and we compare them to the elections results. Furthermore, we study the topics that are associated with the co-occurrence of two politicians in the same tweet. We cannot conclude, from a simple statistical analysis of tweet volume and their time evolution, that it is possible to precisely predict the election outcome (or at least not in our case of study that was characterized by a “too-close-to-call” scenario). On the other hand, we found that the volume of tweets and their change in time provide a very good proxy of the final results. We present this analysis both at a national level and at smaller levels, ranging from the regions composing the country to macro-areas (North, Center, South)

Global value trees

The fragmentation of production across countries has become an important feature of the globalization in recent decades and is often conceptualized by the term “global value chains” (GVCs). When empirically investigating the GVCs, previous studies are mainly interested in knowing how global the GVCs are rather than how the GVCs look like. From a complex networks perspective, we use the World Input-Output Database (WIOD) to study the evolution of the global production system. We find that the industry-level GVCs are indeed not chain-like but are better characterized by the tree topology. Hence, we compute the global value trees (GVTs) for all the industries available in the WIOD. Moreover, we compute an industry importance measure based on the GVTs and compare it with other network centrality measures. Finally, we discuss some future applications of the GVTs