Prestigious Youth are Leaders but Central Youth are Powerful: What Social Network Position Tells us About Peer Relationships.

Measures of social network position provide unique social and relational information yet have not been used extensively by researchers who study peer relationships. This study explored two measures-social network prestige and social network centrality-to improve conceptualization of their similarities, differences, and meaning within a peer relationships context. Prestige and centrality were computed from friendship nominations (N = 396 6th graders; 48% girls; 49% White) and participants nominated peers on several social indicators (e.g., aggressive, popular). Two example classroom networks were examined to visually depict social network position. Associations between measures of social network position and social indicators were examined using correlations and latent profile analysis. Latent profile analysis identified three profiles based on the social indicators, which differentially related to prestige and centrality. Overall, prestigious youth were generally well-liked, prosocial, and leaders, whereas central youth were powerful and aggressive. The results strengthen the conceptualization of these network-based measures, allowing them to be more readily used by peer relationships researchers to understand youth's interaction patterns and behaviors.

Structural Network Position and Performance of Health Leaders Within an HIV Prevention Trial.

The effectiveness of peer leaders in promoting health may depend on the position they occupy within their social networks. Using sociocentric (whole network) and behavioral data from the intervention arm of a cluster-randomized HIV prevention trial in Dar es Salaam, Tanzania, we used generalized linear models with standardized predictors to examine the association between heath leaders' baseline structural network position (i.e., in-degree and betweenness centrality) and their 12-month self-reported (1) confidence in educating network members about HIV and gender-based violence (GBV) and (2) number of past-week conversations about HIV and GBV. As in-degree centrality increased, leaders reported fewer HIV-related conversations. As betweenness centrality increased, leaders reported greater number of conversations about GBV. Network position was not significantly associated with confidence in discussing either topic. Our results suggest that peer leaders who occupy spaces between sub-groups of network members may be more effective in engaging their peers in sensitive or controversial topics like GBV than more popular peer leaders.

Reciprocal Associations between Delinquent Behavior and Social Network Position during Middle School.

Delinquency and social standing are linked within middle school. Yet, theoretical explanations are generally unidirectional, and prevailing models are somewhat contradictory in terms of the directionality of the link between delinquency and social standing. The current study aimed to expand upon our current understanding of the social nature of delinquency by examining reciprocal associations between delinquency and social standing. We conceptualized social standing using two indices of social network position: social network prestige (how important or influential one is within the peer network) and social network centrality (how well-connected one is to peers in the network). We also assessed gender differences in associations. Ethnically diverse middle school students were followed longitudinally across one year (three waves; N = 516, M age = 11.91 years at the first wave; 47% girls; 55% Latina/o). Participants reported on their delinquent behavior and nominated friends within their grade; friendship nominations were used to calculate social network prestige and centrality. Results indicated that both indicators of social network position were associated with increases in delinquency across school years, but not within the school year. Further, delinquency was associated with increases in social network prestige but not social network centrality (again, only across school years). Similarities across gender were found. The findings highlight the need to expand upon current, generally unidirectional theories of the social nature of delinquency, and suggest important differences between change within vs. across the school year.

Adolescent Aggression: The Role of Peer Group Status Motives, Peer Aggression, and Group Characteristics.

Recent studies of youth aggression have emphasized the role of network-based peer influence processes. Other scholars have suggested that aggression is often motivated by status concerns. We integrate these two veins of research by considering the effects of peer status motivations on subsequent adolescent aggression, net of their own status motivations, prior aggression, and peer behavior. We also explore different levels at which peer effects may occur, considering the effects of reciprocated and unreciprocated friendships as well as larger, meso-level peer groups. We anticipate that peer group effects are magnified by both size and boundedness as measured by Freeman's (1972) Segregation Index. We find that, net of the adolescent's aggression at time 1, both the aggressive behaviors and the status valuations of friends independently increase the likelihood of aggression at time 2, six months later. The aggressive behavior of friends who do not reciprocate the adolescent's friendship nomination has particular impact. The average status valuation of peer groups increases their members' likelihood of aggression, even after controlling for their own attitudes about status, their friends' attitudes, and their friends' aggressive behavior. This effect is magnified in large groups and groups with high Freeman segregation scores.

Can Nuclear Power Products Mitigate Greenhouse Gas Emissions? Evidence from Global Trade Network.

Since its birth, nuclear power has been a hot topic of academic research while being subject to much controversy. As a new green energy source with zero greenhouse gas (GHG) emissions, nuclear power plays a vital role in combatting global climate change. Based on global databases and various empirical analysis methods, this study aimed to explore the changes in the global nuclear power product trade (GNT) network and its impact on GHG emissions from 2001 to 2018. The main findings are summarized as follows. (1) Global trade in nuclear power products and GHG emissions showed a non-linear and fluctuating growth during the research period. The geographical pattern of GNT not only has prominent spatial heterogeneity, but it also has some spatial reverse coupled with the spatial distribution of global GHG emissions. (2) The overall regression analysis finds that nuclear power product trade had a significant suppressive effect on global GHG emissions and had the greatest influence among all the selected variables. (3) As for the impact of the GNT network on GHG emissions, nuclear power product trade was better able to curb GHG emissions in countries with the dominate positions compared to those with affiliated positions, which reflects the heterogeneous effect of nuclear power product trade on GHG emissions. These results provide further evidence for the dialectical debate on whether nuclear power products contribute to GHG emissions reductions. This paper also provides corresponding recommendations for policymakers.

Does the social network structure of wild animal populations differ from that of animals in captivity?

The social behaviour of wild animals living in groups leads to social networks with structures that produce group-level effects and position individuals within them with differential consequences for an individual's fitness. Social dynamics in captivity can differ greatly from those in wild conspecifics given the different constraints on social organization in wild populations, e.g. group size, predation pressure, distribution of resources (food, mates), which are all regulated by human carers in captive populations. The social networks of animals in zoos is expected to differ from those of free-living conspecifics. While many studies have described the social networks of a wide diversity of wild and captive animals, none has directly compared the networks of multiple groups of a single species both in the wild and in captivity. Meerkats, Suricata suricatta, are an excellent species to compare the social networks of wild and captive groups. We replicated the methods of Madden et al. (2009, 2011), who studied eight groups in the wild, in fifteen captive groups. We tested how network structures and individual positions in grooming, foraging competition and dominance networks differed between wild and captive groups. Groups of wild and captive meerkats differed in various aspects of their social network structure. Differences in the network may be due to individuals occupying different network positions and the difference in the number and strength of their connections to other individuals. This distinct way of interacting and associating could be a result of group specific attributes, such as group size, and/or the attributes of the donor and recipient, including sex, status or age. Critically, the differences may be explained by the dissimilar living environment that each encounters.

Seasonal changes in metacommunity assembly mechanisms of benthic macroinvertebrates in a subtropical river basin.

Unraveling the ecological factors that control variation in local community structure in space and time is fundamental to metacommunity ecology. In this scenario, environmental filtering and spatial processes are recognized as important drivers of community assembly, yet their relative importance is anticipated to vary for biological communities in different seasons, network positions and organisms with distinct dispersal modes. In this study, we used a dataset (macroinvertebrate communities and environmental variables) collected in different seasons from the Ganjiang River in China to test the above ideas. We divided the whole metacommunity in each season into mainstream communities, tributary communities, strictly aquatic dispersers and aquatic/aerial dispersers, and subsequently used variation partitioning to examine the relative contribution of environmental and spatial factors separately for the overall and decomposed components of the metacommunity. Our results showed that both environmental filtering and spatial processes were important drivers of variation in community structure, yet their explanatory powers varied considerably among seasons. Environmental filtering was the primary driver of metacommunity organization in most scenarios, while the effects of spatial processes surpassing environmental filtering occurred only sporadically. For communities in different network positions, tributary communities were structured by both strong environmental filtering and profound effects of spatial processes via dispersal limitation. However, communities in mainstream sites were mainly determined by environmental filtering, and the effects of spatial processes were almost negligible. Moreover, environmental filtering was clearly more important for aquatic/aerial dispersers, while spatial processes were more influential for strictly aquatic dispersers. We thus concluded that environmental filtering, spatial processes, network position and dispersal mode can interact to regulate metacommunity organization of riverine macroinvertebrates. Considering that the relative contribution of these factors varied among seasons, we strongly uphold the idea that community ecology research should go beyond one-season snapshot surveys in river networks.

How do new members affect the relationship between principal investigator's network position and academic output of granted funds?

The paper focuses on how to improve academic output of a granted fund when the adding of new members changes principal investigator's network position. This objective is refined by exploring how new members affect the relationship between principal investigator's network position and the academic output of granted funds, and whether this effect is similar in high-output and low-output collaboration networks. New members are divided into two groups, namely, international collaboration and inbound mobility. Using negative binomial regression on research funds supported by the National Natural Science Foundation of China, the results indicate that new members indeed have moderating effects on the relationship between principal investigator's network position and the academic output of granted funds. Moreover, we find that this moderating effect in high-output collaboration networks is larger than that in low-output collaboration networks. Our findings provide practical implications for the decision makers to design funding planning and for the principal investigators to improve academic output.

Dynamic Relationships between Information Transmission and Social Connections.

Understanding the drivers of sociality is a major goal in biology. Individual differences in social connections determine the overall group structure and have consequences for a variety of processes, including if and when individuals acquire information from conspecifics. Effects in the opposite direction, where information acquisition and transmission have consequences for social connections, are also likely to be widespread. However, these effects are typically overlooked. We propose that individuals who successfully learn about their environment become valuable social partners and become highly connected, leading to feedback-based dynamic relationships between social connections and information transmission. These dynamics have the potential to change our understanding of social evolution, including how selection acts on behavior and how sociality influences population-level processes.

Social networks and health: a systematic review of sociocentric network studies in low- and middle-income countries.

In low- and middle-income countries (LMICs), naturally occurring social networks may be particularly vital to health outcomes as extended webs of social ties often are the principal source of various resources. Understanding how social network structure, and influential individuals within the network, may amplify the effects of interventions in LMICs, by creating, for example, cascade effects to non-targeted participants, presents an opportunity to improve the efficiency and effectiveness of public health interventions in such settings. We conducted a systematic review of PubMed, Econlit, Sociological Abstracts, and PsycINFO to identify a sample of 17 sociocentric network papers (arising from 10 studies) that specifically examined health issues in LMICs. We also separately selected to review 19 sociocentric network papers (arising from 10 other studies) on development topics related to wellbeing in LMICs. First, to provide a methodological resource, we discuss the sociocentric network study designs employed in the selected papers, and then provide a catalog of 105 name generator questions used to measure social ties across all the LMIC network papers (including both ego- and sociocentric network papers) cited in this review. Second, we show that network composition, individual network centrality, and network structure are associated with important health behaviors and health and development outcomes in different contexts across multiple levels of analysis and across distinct network types. Lastly, we highlight the opportunities for health researchers and practitioners in LMICs to 1) design effective studies and interventions in LMICs that account for the sociocentric network positions of certain individuals and overall network structure, 2) measure the spread of outcomes or intervention externalities, and 3) enhance the effectiveness and efficiency of aid based on knowledge of social structure. In summary, human health and wellbeing are connected through complex webs of dynamic social relationships. Harnessing such information may be especially important in contexts where resources are limited and people depend on their direct and indirect connections for support.

Effects of genetic variants of ADH1B and ALDH2 and social network on continued alcohol drinking among young adolescents in Taiwan.

BACKGROUND: This study aimed (i) to evaluate the effects of genetic variants of ADH1B and ALDH2 and social network position on continued alcohol use in early adolescence, and (ii) to explore possible moderating role of pubertal development on genetic effects. METHODS: The sample comprised 496 children who ever drank alcohol before the ages of 10-12. Information pertaining to sociodemographic background, pubertal development, parental drinking, alcohol and tobacco use, alcohol-metabolizing genes, and nominated best friends was collected in four waves of assessment. Polymorphisms of ADH1B (rs1229984) and ALDH2 (rs671) were genotyped. The latent class analysis was first used to characterize longitudinal alcohol use pattern, followed by the multinomial logistic regression analyses to assess its association with genes, pubertal development, and social network. RESULTS: Three distinct classes of alcohol users (i.e. ex-drinkers, sporadic drinkers, and continued drinkers) were derived from alcohol-experienced children. Both alcohol-metabolizing genes appear to have protective effects, yet such relationships were only significant for youngsters in pre-to-early pubertal stage: the adjusted odds ratio (aOR) of ADH1B fast-genotype for sporadic drinkers was 0.46 and that of ALDH2 slow-genotype for both sporadic and continued drinkers was 0.47 and 0.42, respectively. Children having the bridge position in their peer network were more likely to be sporadic drinkers (aOR=4.15) and continued drinkers (aOR=3.16). CONCLUSIONS: Our results illustrate a potential moderating effect of pubertal development on the protective influence of alcohol-metabolizing genes on subsequent alcohol use among alcohol-experienced children as well as the independent contribution of early life's social network to their alcohol involvement.