Fact-checking strategies to limit urban legends spreading in a segregated society

We propose a framework to study the spreading of urban legends, i.e., false stories that become persistent in a local popular culture, where social groups are naturally segregated by virtue of many (both mutable and immutable) attributes. The goal of this work is identifying and testing new strategies to restrain the dissemination of false information, focusing on the role of network polarization. Following the traditional approach in the study of information diffusion, we consider an epidemic network-based model where the agents can be ‘infected’ after being exposed to the urban legend or to its debunking depending on the belief of their neighborhood. Simulating the spreading process on several networks showing different kind of segregation, we perform a what-if analysis to compare strategies and to understand where it is better to locate eternal fact-checkers, nodes that maintain their position as debunkers of the given urban legend. Our results suggest that very few of these strategies have a chance to succeed. This apparently negative outcomes turns out to be somehow surprising taking into account that we ran our simulations under a highly pessimistic assumption, such that the ‘believers’, i.e., agents that accepted as true the urban legend after they have been exposed to it, will not change their belief no matter of how much external or internal additional informational sources they access to. This has implications on policies that are supposed to decide which strategy to apply to stop misinformation from spreading in real world networks

Capire la diffusione della disinformazione e come contrastarla

La proliferazione di fake news è uno dei temi più discussi degli ultimi anni: un problema non nuovo, ma amplificato dalle nuove tecnologie digitali che permettono scambi di informazioni sempre più rapidi e disintermediati. Proponiamo qui un modello per studiare la diffusione della disinformazione come un processo virale in cui bufale e relative smentite (debunking) competono tra loro, focalizzando la nostra attenzione soprattutto sul ruolo della struttura (topologia) della rete sociale sottostante. La segregazione strutturale aiuta o limita la propagazione? Le simulazioni del nostro modello mostrano che la risposta non è univoca. Infine consideriamo possibili strategie per suggerire policies efficaci e potenziare piattaforme di fact-checking

Structural inequalities emerging from a large wire transfers network

We aim to explore the connections between structural network inequalities and bank’s customer spending behaviours, within an entire national ecosystem made of natural persons (i.e., an individual human being) and legal entities (i.e., private or public organisations), different business sectors, and supply chains that span distinct geographical regions. We focus on Italy, that is among the wealthiest nations in the world, and also an example of a complex economic system. In particular, we had access to a large subset of anonymised and GDPR-compliant wire transfer data recorded from Jan 2016 to Dec 2017 by Intesa Sanpaolo, a leading banking group in the Eurozone, and the most important one in Italy.Intesa Sanpaolo wire transfers network exhibits a strong heavy-tailed behaviour and a giant component that grows continuously around the same core of the 1% highest degree nodes, and it also shows a general disassortative pattern, even if some ranges of degrees’ values stand out from the trend. Structural heterogeneity is explored further by means of a bow-tie analysis, that shows clearly that the majority of relevant, in terms of transferred amount, transactions is settled between a smaller set of nodes that are associated to legal entities and that mostly belong to the strongly connected component. This observation brings to a more comprehensive inspection of differences between Italian regions and business sectors, that could support the detection and the understanding of the interplay between supply chains.Our results suggest that there is a general flow of money that seems to stream down from higher degree legal entities to lower degree natural persons, crossing Italian regions and connecting different business sectors, and that is finally redistributed through expenses sharing within families and smaller communities. We also describe a reference dataset and an empirical contribution to the study on financial networks, focusing on finer-grained information concerned about spending behaviour through wire transfers

Extracting Graph Topological Information and Users’ Opinion

This paper focuses on the role of social relations within social media in the formation of public opinion. We propose to combine the detection of the users’ stance towards BREXIT, carried out by content analysis of Twitter messages, and the exploration of their social relations, by relying on social network analysis. The analysis of a novel Twitter corpus on the BREXIT debate, developed for our purposes, shows that like-minded individuals (sharing the same opinion towards the specific issue) are likely belonging to the same social network community. Moreover, opinion driven homophily is exhibited among neighbours. Interestingly, users’ stance shows diachronic evolution

Stance Polarity in Political Debates: a Diachronic Perspective of Network Homophily and Conversations on Twitter

[EN] In the last decade, social media gained a very significant role in public debates, and despite the many intrinsic difficulties of analyzing data streaming from on-line platforms that are poisoned by bots, trolls, and low-quality information, it is undeniable that such data can still be used to test the public opinion and overall mood and to investigate how individuals communicate with each other. With the aim of analyzing the debate in Twitter on the 2016 referendum on the reform of the Italian Constitution, we created an Italian annotated corpus for stance detection for automatically estimating the stance of a relevant number of users. We take into account a diachronic perspective to shed lights on users' opinion dynamics. Furthermore, different types of social network communities, based on friendships, retweets, quotes, and replies were investigated, in order to analyze the communication among users with similar and divergent viewpoints. We observe particular aspects of users' behavior. First, our analysis suggests that users tend to be less explicit in expressing their stances after the outcome of the vote; simultaneously, users who exhibit a high number of cross-stance relations tend to become less polarized or to adopt a more neutral style in the following phase of the debate. Second, despite social media networks are generally aggregated in homogeneous communities, we highlight that the structure of the network can strongly change when different types of social relations are considered. In particular, networks defined by means of reply-to messages exhibit inverse homophily by stance, and users use more often replies for expressing diverging opinions, instead of other forms of communication. Interestingly, we also observe that the political polarization increases forthcoming the election and decreases after the election day.The work of Viviana Patti and Giancarlo Ruffo was partially funded by the Fondazione CRT under research project the Hate Speech and Social Media (2016.0688), and the "Progetto di Ateneo/CSP 2016" under research project "Immigrants, Hate and Prejudice in Social Media" (S1618_L2_BOSC_01). The work of Paolo Rosso was partially funded by the Spanish MICINN under the research project "MISMIS-FAKEnHATE on Misinformation and Miscommunication in social media: FAKE news and HATE speech" (PGC2018-096212-B-C31).Lai, M.; Tambuscio, M.; Patti, V.; Ruffo, G.; Rosso, P. (2019). Stance Polarity in Political Debates: a Diachronic Perspective of Network Homophily and Conversations on Twitter. Data & Knowledge Engineering. 124:1-20. https://doi.org/10.1016/j.datak.2019.101738S12012

Ruolo dei farmaci antinfiammatori e antileucotrienici nel prevenire la fibrosi capsulare periprotesica nella ricostruzione mammaria post oncologica

Capsular tissue around silicone breast implants is a normal inflammatory reaction versus a foreign body. Capsular hypertrophy and contraction is an abnormal scar reaction to the implant and it is actually the main factor causing a poor aesthetic results of mammary reconstruction after oncologic surgery. We evaluated the efficiency of new NSAD (cox2 ihnibitors - etoricoxib) and anti-leuckotriene drugs (zafirlukast) in preventing capsular contraction around silicone breast implants. A selection of women scheduled for mastectomy and immediate reconstruction with tissue expander has been raodnomized in three groups. Group A has been treated with etoricoxib during inflating period. Grop B has been treated with zafirlukast in the same period. Gorup C didn’t take any drug (control group). After expansion we evaluated hystologically the capsular tissue (thickness, cells, structural proteins), local cytokine expression (IL2- TGF Beta) and systemic concentrations of MMP and TIMP. We also assessed expansion velocity and inflating volumes during expansion. Etoricoxib and zafirlukast has been proved to be efficient in preventing capsular contraction around breast implants. The less collateral effects of zafirlukast make the drug of choice in mammary reconstruction.La capsula, tessuto neoformato attorno agli impianti mammari in gel di silicone (espansori tessutali e protesi), costituisce una reazione fibrotica da corpo estraneo. Il risultato finale della ricostruzione mammaria, a distanza di tempo, è esteticamente naturale e ben tollerato dalla paziente in misura inversamente proporzionale all'entità di tale reazione (e quindi all'ipertrofia della capsula stessa). Una selezione di pazienti sottoposte a mastectomia per motivi oncologici e a ricostruzione mammaria con protesi, previa espansione cutanea con espansore riempito di soluzione salina, è stata suddivisa in 3 gruppi di studio. Di essi i primi due sono stati sottoposti rispettivamente a trattamento farmacologico (durante tutta la fase di espansione) con farmaci antinfiammatori Cox2ib (etoricoxib) e antileucotrienici anti-LTC4, LTD4, LTE4 (zafirlukast). Il terzo gruppo (di controllo) non è stato sottoposto ad alcuna terapia. Durante l'espansione cutanea sono stati eseguiti prelievi ematici per il dosaggio sierologico dei marcatori indice di reazione fibrotica in particolare le metalloproteinasi MMP e i loro inibitori tissutali TIMP1 e TIMP2. Sono stati inoltre misurati strumentalmente i trend pressori di espansione per quantificare il grado di resistenza e la compliance del tessuto capsulare. Al termine dell'espansione è stato eseguito un prelievo di tessuto capsulare per analisi istologiche quali la misurazione degli spessori (massimo, minimo e medio) e lo studio delle componenti indice di reazione fibrotica (collagene I e IV, fibroblasti, macrofagi, miofibroblasti). Sono state inoltre dosate l'espressione genica tissutale di TGFβ e IL-2. I dati raccolti sono stati inseriti in un algoritmo valutativo per capire se e quale principio farmacologico fosse maggiormente efficace nell'inibire la fibrosi capsulare periprotesica. L’etoricoxib e lo zafirlukast si nono dimostrati complessivamente efficaci nel prevenire e ridurre la contrattura capsulare periprotesica. L’attività dei cox2 inibitori è risultata maggiore rispetto agli inibitori dei leucotrieni. Tuttavia la potenziale cardiotossicità dei primi, contrapposta ai bassissimi effetti collaterali dei secondi fanno preferire lo zafirlukast come farmaco di prima scelta nella ricostruzione mammaria post oncologica con materiali protesici

Capire la diffusione della disinformazione e come contrastarla

La proliferazione di fake news è uno dei temi più discussi degli ultimi anni: un problema non nuovo, ma amplificato dalle nuove tecnologie digitali che permettono scambi di informazioni sempre più rapidi e disintermediati. Proponiamo qui un modello per studiare la diffusione della disinformazione come un processo virale in cui bufale e relative smentite (debunking) competono tra loro, focalizzando la nostra attenzione soprattutto sul ruolo della struttura (topologia) della rete sociale sottostante. La segregazione strutturale aiuta o limita la propagazione? Le simulazioni del nostro modello mostrano che la risposta non è univoca. Infine consideriamo possibili strategie per suggerire policies efficaci e potenziare piattaforme di fact-checking

Worst-case (in)efficiency of a congested network game on equilibria and Edgeworth cycles

1 Introduction 1.1 Related Work 1.2 Notations 2 The model 2.1 General Description 2.2 Solution Concepts 2.3 Elastic demand variant 3 Linear Latencies: existence of provider equilibria 3.1 Best-Response dynamics 3.2 Convergence 4 Bound on efficiency of provider equilibria 4.1 Price of Anarchy 4.2 PoA of provider equilibria with non-smooth latencies 5 Non-smooth latencies and Edgeworth cycles 5.1 Non-existence of PE for higly convex latencies 5.2 Edgeworth cycles 5.3 Efficiency of cycles 6 Conclusion