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In this paper, we investigate the relational architecture of the Intergovernmental Panel on Climate Change (IPCC) focussing on the individuals that, in the thirty years of its existence, have assured the connection between its different components. To study relational bridging within the IPCC, we created a unique database of all the individuals who have contributed to the organisation since its establishment and noted in which workstream they participated (i.e., function + Working Group + Assessment Report). From this database we extract the participants-workstreams affiliation network and use it to compute several metrics of bridgeness, which we discuss, validate, and compare. We use these metrics to investigate the general distribution and evolution of bridging in the IPCC, but also to identify individuals who more actively provided connections between its authors and government representatives (functional bridges), its Working Groups (thematic bridges) and its assessment cycles (temporal bridges). Focussing on the role of key bridge individuals and their trajectories within the organisation, we provide insights on the IPCC as a network organisation. • The paper is based on an original dataset of more than 8000 individuals who have contributed to the IPCC since 1988. • The paper investigates the individuals who have contributed to keeping together the different components of the IPCC. • The paper identifies temporal, thematic and functional bridge individuals and qualitatively analyses their career in the IPCC. [ABSTRACT FROM AUTHOR]

Chronic disease has profound impacts on the structural features of individuals' interpersonal connections such as bridging — ties to people who are otherwise poorly connected to each other. Prior research has documented competing arguments regarding the benefits of network bridging, but less is known about how chronic illness influences bridging and its underlying mechanisms. Using data on 1555 older adults from the National Social Life, Health, and Aging Project (NSHAP), I find that older adults diagnosed with chronic illness tend to have lower bridging potential in their networks, particularly between kin and non-kin members. They also report more frequent interactions with close ties but fewer neighbors, friends, and colleagues in their networks, which mediates the association between chronic illness and social network bridging. These findings illuminate both direct and indirect pathways through which chronic illness affects network bridging and highlight the context-specific implications for social networks in later life. • The paper discusses context-specific implications for social network bridging potential in a novel context of chronic health. • Older adults' bridging potential in personal networks are classified into three distinct types. • Chronic illnesses directly and only reduce the likelihood of bridging kin and non-kin members. • The declining non-kin informal ties accelerate the adverse association between chronic illnesses and social network bridging. [ABSTRACT FROM AUTHOR]

When the coronavirus emerged in early 2020, older adults were at heightened risk of contracting the virus, and of suffering mental health consequences from the pandemic and from the precautions designed to mitigate it. In this paper, we examine how social networks prior to the pandemic helped to shape health beliefs, behaviors, and outcomes among older adults during its onset, focusing on (1) perceived risk of COVID-19, (2) preventative health behaviors, and (3) mental health, including loneliness, perceived stress, depression, and anxiety. Drawing on the longitudinal Social Networks in Alzheimer Disease study, we find that networks high in bridging social capital predict greater perceived risk and more precautions taken, but worse mental health. In contrast, networks high in bonding social capital predict less perceived risk and fewer precautions taken, but better mental health. We discuss this apparent tradeoff between physical and mental health. • We examined how the networks of older adults influenced their health beliefs, behaviors, and mental health outcomes during the pandemic. • We divided social network characteristics into two broad categories: bonding social capital and bridging social capital. • Findings suggest an apparent tradeoff between preventing infection and promoting mental health depending on one's network. [ABSTRACT FROM AUTHOR]

Social networks are often structured in such a way that there are gaps, or “structural holes,” between regions. Some actors are in the position to bridge or span these gaps, giving rise to individual advantages relating to brokerage, gatekeeping, access to non-redundant contacts, and control over network flows. The most widely used measures of a given actor’s bridging potential gauge the extent to which that actor is directly connected to others who are otherwise not well connected to each other. Unfortunately, the measures that have been developed to identify structural holes cannot be adapted directly to two-mode networks, like individual-to-organization networks. In two-mode networks, direct contacts cannot be directly connected to each other by definition, making the calculation of redundancy, effective size, and constraint impossible with conventional one-mode methods. We therefore describe a new framework for the measurement of bridging in two-mode networks that hinges on the mathematical concept of the intersection of sets. An actor in a given node class (“ego”) has bridging potential to the extent that s/he is connected to actors in the opposite node class that have unique profiles of connections to actors in ego’s own node class. We review the relevant literature pertaining to structural holes in two-mode networks, and we compare our primary bridging measure (effective size) to measures of bridging that result when using one-mode projections of two-mode data. We demonstrate the results of applying our approach to empirical data on the organizational affiliations of elites in a large U.S. city. [ABSTRACT FROM AUTHOR]

Valente and Fujimoto (2010) proposed a measure of brokerage in networks based on Granovetter's classic work on the strength of weak ties. Their paper identified the need for finding node-based measures of brokerage that consider the entire network structure, not just a node's local environment. The measures they propose, aggregating the average change in cohesion for a node's links, has several limitations. In this paper we review their method and show how the idea can be modified by using betweenness centrality as an underpinning concept. We explore the properties of the new method and provide point, normalized, and network level variations. This new approach has two advantages, first it provides a more robust means to normalize the measure to control for network size, and second, the modified measure is computationally less demanding making it applicable to larger networks. [ABSTRACT FROM AUTHOR]

This paper proposes several measures for bridging in networks derived from insight that links which reduce distances in a network are important structural bridges. Bridging is calculated by systematically deleting links and calculating the resultant changes in network cohesion (measured as the inverse average path length). The average change for each node's links provides an individual level measure of bridging. We also present a normalized version which controls for network size and a network-level bridging index. Bridging properties are demonstrated on hypothetical networks, empirical networks, and a set of 100 randomly generated networks to show how the bridging measure correlates with existing network measures such as degree, personal network density, constraint, closeness centrality, betweenness centrality, and vitality. Bridging and the accompanying methodology provide a family of new network measures useful for studying network structure, network dynamics, and network effects on substantive behavioral phenomenon. [Copyright &y& Elsevier]