Neutrino emission from BL Lac objects: the role of radiatively inefficient accretion flows

The origin of the astrophysical high-energy neutrinos discovered by IceCube is currently a major mystery. The recent detection of IceCube-170922A, a $\sim$300 TeV neutrino potentially correlated with the flaring $\gamma$-ray source TXS 0506+056, directs attention toward BL Lac objects (BL Lacs), the subclass of blazars with weak emission lines. While high-energy neutrinos can be produced via photohadronic interactions between protons accelerated in their jets and ambient low-energy photons, the density of the latter in such objects had generally been thought to be too low for efficient neutrino emission. Here we consider the role of radiatively inefficient accretion flows (RIAFs), which can plausibly exist in the nuclei of BL Lacs, as the source of target photons for neutrino production. Based on simple model prescriptions for the spectra of RIAFs at different accretion rates, we find that they can be sufficienly intense to allow appreciable neutrino emission for the class of low-synchrotron-peak BL Lacs such as TXS 0506+056. In constrast, for high-synchrotron-peak BL Lacs including Mkn 421 and Mkn 501, the contribution of RIAFs is subdominant and their neutrino production efficiency can remain low, consistent with their non-detection by IceCube to date.Comment: 5 pages, 4 figures, accepted to MNRAS as Lette

Campaign Spending and Rents in a Probabilistic Voting Model

How the levels of corruption and embezzlement of a political system are influenced by electoral campaigns? How rent extraction can be reduced with anti-corruption policies? We answer these questions in the context of a probabilistic voting model characterized by the absence of political pressure groups and by the presence of ideological voters whose preferences can be manipulated by political candidates through campaign spending. Our main innovation is the introduction of an analysis of candidates\u2019 campaign choices in the literature on the agency costs of political delegation. Moreover, we contribute to the literature establishing a direct link between campaign expenditures and the utility of the voters. We find that campaigning choices are orthogonal to decisions about rent extractions and that candidates always invest a significative amount of their resources of their expected rents in advertisements. As the electoral competition itself does not suffices to reach an efficient outcome, we then study how welfare policies can reduce the inefficiencies of the electoral competition. We show that limitations of campaign expenditures are, in absence of lobbies, always welfare decreasing for voters. Indeed, our main policy suggestion is to introduce an anti-corruption, i.e. a policy that reduces the ability of candidates to extract rents by abating the incentives to rent accumulation. We show that the introduction of such tax can make the citizens better off. Surprisingly, it may also make the candidates better off if the policy is not sufficiently funded. Finally, we establish the conditions under which a policy of this kind can achieve the popular support required for an effective implementation and we show that these conditions are difficult to achieve in countries with large income inequalities

Reflectivity relates differently to pro sociality in na\uefve and strategic subjects

Is pro sociality a natural impulse or the result of a self-controlled behavior? We investigate this issue in a lab in the field experiment with participants from the general adult population in Italy. We find two key results: first, that there is a positive relationship between pro sociality and strategic reasoning. Second, that reflectivity relates to lower pro sociality but only among strategic subjects, indicating that the intuitive view of pro sociality is valid only among strategic individuals. Non-strategic individuals are instead intuitively selfish. We surmise that these results emerge due to a common cognitive root between strategizing and pro sociality, namely empathy

Multilayer Network Analysis of Innovation Intermediaries' Activities

Policymakers wishing to enhance innovation processes in small and medium-sized enterprises increasingly channel their interventions through innovation intermediaries. However, limited empirical research exists regarding the activities and performance of intermediaries, with most contributions taking a qualitative approach and focusing on the role of intermediaries as brokers. In this paper, we analyse the extent to which innovation intermediaries, through their engagement in different activities, support the creation of communities of other agents. We use multilayer network analysis techniques to simultaneously represent the many types of interactions promoted by intermediaries. Furthermore, by originally applying the Infomap algorithm to our multilayer network, we assess the contribution of the agents involved in different activities promoted by intermediaries, and we identify the emerging multilayer communities and the intercohesive agents that span across several communities. Our analysis highlights the potential and the critical features of multilayer analysis for policy design and evaluation

Parallel versus Sequential Update and the Evolution of Cooperation with the Assistance of Emotional Strategies

Our study contributes to the debate on the evolution of cooperation in the single-shot Prisoner's Dilemma (PD) played on networks. We construct a model in which individuals are connected with positive and negative ties. Some agents play sign-dependent strategies that use the sign of the relation as a shorthand for determining appropriate action toward the opponent. In the context of our model in which network topology, agent strategic types and relational signs coevolve, the presence of sign-dependent strategies catalyzes the evolution of cooperation. We highlight how the success of cooperation depends on a crucial aspect of implementation: whether we apply parallel or sequential strategy update. Parallel updating, with averaging of payoffs across interactions in the social neighborhood, supports cooperation in a much wider set of parameter values than sequential updating. Our results cast doubts about the realism and generalizability of models that claim to explain the evolution of cooperation but implicitly assume parallel updating

Much ado about making money: The impact of disclosure, news and rumors over the formation of security market prices over time

This article develops an agent-based model of security market pricing process, capable to capture main stylised facts. It features a collective market pricing mechanism based upon evolving heterogenous expectations that incorporate signals of security issuer fundamental performance over time. Distinctive signaling sources on this performance correspond to institutional mechanisms of information diffusion. These sources differ by duration effect (temporary, persistent, and permanent), confidence, and diffusion degree among investors over space and time. Under full and immediate diffusion and balanced reaction by all the investors, the value of these sources should be consistently and timely integrated by the market price process, implying efficient pricing. By relaxing these quite heroic conditions, we assess the impact of distinctive information sources over market price dynamics, through financial systemic properties such as market price volatility, exuberance and errancy, as well as market liquidity. Our simulation analysis shows that transient information shocks can have permanent effects through mismatching reactions and self-reinforcing feedbacks, involving mispricing in both value and timing relative to the efficient market price series. This mispricing depends on both the information diffusion process and the ongoing information confidence mood among investors over space and time. We illustrate our results through paradigmatic cases of stochastic news, before generalising them to autocorrelated news. Our results are further corroborated by robustness checks over the parameter space

Reputation and punishment sustain cooperation in the optional public goods game

Cooperative behaviour has been extensively studied as a choice between cooperation and defection. However, the possibility to not participate is also frequently available. This type of problem can be studied through the optional public goods game. The introduction of the 'Loner' strategy' allows players to withdraw from the game, which leads to a cooperator-defector-loner cycle. While pro-social punishment can help increase cooperation, anti-social punishment - where defectors punish cooperators - causes its downfall in both experimental and theoretical studies. In this paper, we introduce social norms that allow agents to condition their behaviour to the reputation of their peers. We benchmark this with respect both to the standard optional public goods game and to the variant where all types of punishment are allowed. We find that a social norm imposing a more moderate reputational penalty for opting out than for defecting increases cooperation. When, besides reputation, punishment is also possible, the two mechanisms work synergically under all social norms that do not assign to loners a strictly worse reputation than to defectors. Under this latter set-up, the high levels of cooperation are sustained by conditional strategies, which largely reduce the use of pro-social punishment and almost completely eliminate anti-social punishment. This article is part of the theme issue 'The language of cooperation: reputation and honest signalling'

Reflexivity reduces pro-sociality but only among strategic subjects

Is pro-sociality a natural impulse or the result of a self-controlled behavior? The literature is not quite univocal on the cognitive mechanisms behind this key feature of observed human behavior. We investigate this issue in a lab in the field experiment with participants selected among the general adult population in Italy. We test prosociality with a Distribution game (or three player dictator game), reflexive versus impulsive behavior with an extended version of the Cognitive Reflection Test and strategic reasoning with the guessing game. In the latter, we request to participants to provide also a motivation of the choice they made in the game. We find two important results: first, that there is a positive relationship between pro-sociality and strategic reasoning. Second, reflexivity reduces pro-sociality but only among strategic subjects. Our results support the intuitive view of pro-sociality: naive individuals that do not control their impulses behave pro-socially, while among strategic subjects the ability to suppress the pro-social impulse is achieved by those subjects making a more selfcontrolled and reflexive choice

Enhancing the resilience of social infrastructures: issues on agents, artefacts and processes. Proceedings of the 2016 Modena Workshop

In the social sciences domain, the term 'resilience' is usually associated to a wide set of changes that affect people and their communities. In particular, both the Hyogo Framework for Action 2005–2015 and the Sendai Framework explicitly focus on the way in which communities face both natural and man-made hazards. To this respect, both material and non-material infrastructures play a critical role, hence deserving a specific focus when assessing local communities' level of resilience. Among them, this paper focuses on: health services, social services, government (according to a multi-level perspective, from the national to the local level), communication infrastructure (i.e. specific tools to interconnect all aforementioned networks). Firstly, this paper discusses some of the most important issues and theoretical frameworks that should be addressed in the analysis of the processes of enhancing the resilience of social infrastructures. Secondly, the discussion that took place in a workshop promoted in May 2016 as the outcome of a one-year dialogue across a group of EU researchers is returned. The debate moves from some theoretical perspectives on resilience and it eventually returns some case studies and real experiences, such as the actions of local governments and the role of risk communication