To date, single-molecule RNA science has been developed almost exclusively around the effect of metal ions as folding promoters and stabilizers of the RNA structure. Here, we introduce a novel strategy that combines single-molecule Förster resonance energy transfer (FRET) and chemical denaturation to observe and manipulate RNA dynamics. We demonstrate that the competing interplay between metal ions and denaturant agents provides a platform to extract information that otherwise will remain hidden with current methods. Using the adenine-sensing riboswitch aptamer as a model, we provide strong evidence for a rate-limiting folding step of the aptamer domain being modulated through ligand binding, a feature that is important for regulation of the controlled gene. In the absence of ligand, the rate-determining step is dominated by the formation of long-range key tertiary contacts between peripheral stem-loop elements. In contrast, when the adenine ligand interacts with partially folded messenger RNAs, the aptamer requires specifically bound Mg2+ ions, as those observed in the crystal structure, to progress further towards the native form. Moreover, despite that the ligand-free and ligand-bound states are indistinguishable by FRET, their different stability against urea-induced denaturation allowed us to discriminate them, even when they coexist within a single FRET trajectory; a feature not accessible by existing methods.

Culture represents the broad range of things over which people influence each other, and frequently contributes to the behaviour, interaction and outlook of groups. Although it has been studied in the context of humans, it is also relevant to future intelligent cognitive systems, that could have the capability to update their disposition and strategy based on the influence of others.In this work we transfer concepts from social sciences to the computing sciences and examine the effect of peer influence on culture. We consider the notion of "peer pressure", being the combined effect from all an individual's neighbours exerting influence at the same time, and also through influence flowing from indirect sources. This approach is derived using Social Impact Theory. We benchmark this against the cultural polarisation model from Axelrod, which involves influence being restricted to dyadic interactions between agents.We find that peer pressure provides complex contagion with a significant impact on cultural evolution. Greater cultural diversity is maintained, with indirect paths mitigating this by effectively forming disruptive weak links. This reaffirms that maintaining diversity in social ties, as well as a wide breadth, supports the mitigation of cultural isolation and polarisation. The model provides a platform to explore culture in a wide range of further scenarios, including electronic, coalition and organisational contexts.

Cultural spread in social networks and organisations is an important and longstanding issue. In this paper we assess this role of tree structures in facilitating cultural diversity. Cultural features are represented using abstract traits that are held by individual agents, which may transfer when neighbouring agents interact through the network structure. We use an agent-based model that incorporates both the combined social pressure and influence from an agent's neighbours. We perform a multivariate study where the number of features and traits representing culture are varied, alongside the breadth and depth of the tree. The results reveal interesting findings on cultural diversity. Increasing the number of features promotes strong convergence in flatter trees as compared to narrower and deeper trees. At the same time increasing features causes narrower deeper trees to show greater cultural pluralism while flatter trees instead show greater cultural homogenisation. We also find that in contrast to previous work, the polarisation between nodes does not rise steadily as the number of traits increase but under certain conditions may also fall. The results have implications for organisational structures -in particular for hierarchies where depth supports cultural divergence, while breadth promotes greater homogeneity, but with increased coordination overhead on the root nodes. These observations also support subsidiarity in deep organisational structures -it is not just a case of communication length promoting subsidiarity, but local cultural differences are more likely to be sustained within these structures.

Psychological theories of inter-group behaviour offer justified representations for interaction, influence, and motivation for coalescence. Agent-based modelling of this behaviour, using evolutionary approaches, further provides a powerful tool to examine the implications of these theories in a dynamic context. In particular, this can enhance our understanding of the escalation of hostility and warfare, and its mitigation, contributing to policy and interventions. In this paper we propose a framework through which social psychology can be embedded in computation for the examination of inter-group behaviour. We examine how various social-psychological theories can be embedded in evolutionary models, and identify ways in which visualisation can support the objective assessment of emergent behaviour. We also discuss how real-world data can be used to parameterise scenarios on which modelling is conducted.