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961.
Landscape urbanization threatens plant phylogenetic diversity in the Brazilian Atlantic Forest 总被引:1,自引:0,他引:1
Valdecir Silva-Junior Danielle G. Souza Rubens T. Queiroz Luiz G. R. Souza Elâine M. S. Ribeiro Bráulio A. Santos 《Urban Ecosystems》2018,21(4):625-634
Urbanization causes species loss around the world, but its effects on phylogenetic diversity are poorly known in tropical forests. Using a patch-landscape approach in an urbanizing region of the Brazilian Atlantic Forest, we tested whether the increase in landscape urbanization reduces plant species density, phylogenetic richness and divergence, and increases the relatedness among co-occurring individuals and species. We assessed plant responses to urbanization in adult (diameter at breast height?>?10 cm) and sapling communities (2.5–10 cm diameter) separately, as saplings are proxies of the future flora. We sampled 2860 woody plants belonging to 155 species in nine circular landscapes with urbanization level varying from 0% to 45%, and estimated the relatedness among the species that have increased and decreased in relative abundance in more urbanized landscapes (winner and losers, respectively). As expected, species density and phylogenetic richness decreased with the increase in urbanization. These responses were consistent for adult and sapling communities, suggesting a persistent loss of species and lineages in more urbanized landscapes. Contrary to our expectations, phylogenetic divergence and structure did not respond to urbanization, indicating that the more urbanized landscapes still retain much evolutionary history. However, because the relatedness among winners was greater than among losers, it is likely that the phylogenetic divergence gradually reduces and the relatedness increases, resulting in impoverished forests with uncertain ability to provide ecosystem services such as carbon storage and pest control. This environmental cost should be taken into account to align urban sprawl with biodiversity conservation. 相似文献
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In this article, we share results from a comparative study exploring the dynamics of community engagement surrounding local water advocacy organizations in two Canadian communities. Although emergent local issues and the perception of crisis triggered some short-term community engagement, social factors such as collective identity, a sense of community, and sense of efficacy appear to be more important for sustaining and deepening engagement. Drawing on the results, we show how the pyramid of engagement, by depicting activist engagement as a multilevel, developmental process, can serve as a useful tool for community engagement scholars and practitioners alike. 相似文献
965.
Ellen Groenestein Alexander J. A. M. van Deursen Menno D. T. de Jong 《Information, Communication & Society》2018,21(8):1168-1185
A common risk among adolescents is sexual solicitation, in which an adolescent is asked to provide sexual information, engage in sexual talk, or in sexual activities. Although scholars increasingly address this topic from an intrapersonal perspective, there is little attention to factors of language use and message content. In two focus group studies, we investigated whether adolescent girls consider themselves capable of assessing whether an online stranger is an adult or a peer, the extent to which adolescent girls actually succeed in making this assessment, the strategies they apply to do so, and the content- and language-related cues focused on. Our findings suggest that most of the adolescent girls are confident in their ability to assess whether the stranger is a peer or an adult with possible sexual intentions. However, we also found that only 43% were able to correctly make this assessment. Most of the adolescents seem to apply the passive strategy of uncertainty reduction: They scan the profile page of the stranger, check contact information, and the profile picture. They may choose to apply the interactive strategy to find out more about the online stranger. Important content-related cues that alarm adolescent girls are: ignoring personal questions, showing an exaggerated amount of interest, acting as a friend, and being sexually oriented. Language cues mentioned related to word usage, abbreviations, sentence length, and tone. 相似文献
966.
Using a grounded theory approach, this study evaluated narratives from a sample of 170 emancipated foster youth (66.5% female; 84.6% non-white) as they reflected on their experiences between the ages of 18 and 25 across three data waves. Corbin and Strauss’ (1990) three-phase coding process revealed five overarching themes: adult values and characteristics, nature of the transition process, material needs and resources, relationship concerns, and affective experiences. Although some elements of Arnett’s (2000) model of emerging adulthood were evident in this sample of emancipated foster youth, such as individualistic qualities and instability, other core features were rarely discussed, such as self-focus and optimism, or were expressed in unique ways, such as exploration and feeling in-between. There were significant age-related changes, but not gender differences, in youth’s discussion of varied themes. These findings suggest promising avenues for intervention during the sensitive period of developmental reorganization that characterizes the transition from adolescence to young adulthood. 相似文献
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Aaron C. Weinschenk Costas Panagopoulos Karly Drabot Sander van der Linden 《Social Influence》2018,13(2):53-64
In this paper, we re-analyze data from a large-scale field experiment (N = 344,084) on voter turnout in order to determine whether men and women respond differently to social pressure aimed at voter mobilization. To date, there have been mixed results regarding the interaction between a person’s gender and receptivity to social influence. On the whole, our analyses confirm prior findings that social pressure increases voter turnout but uncover little to no evidence of gender differences in receptivity to social pressure cues in the context of political participation. 相似文献
969.
Philippe Jean-Luc Gradidge Shane A. Norris Richard Munthali Nigel J. Crowther 《European review of aging and physical activity》2018,15(1):6
Background
The increasing prevalence of obesity in sub-Saharan African women is not well understood, and black South African women in the region are particularly vulnerable. This study aimed to examine whether the relationship of socioeconomic status (SES) with changes in body mass index (BMI) and waist circumference (WC) is mediated by physical activity in ageing African women.Methods
In a longitudinal analysis of the 518 caregivers associated with the Birth to Twenty Plus study, the role of SES associated with 10-year changes in BMI and WC was tested using structural equation modelling (SEM). The degree of mediation of moderate-vigorous physical activity (MVPA) and sitting time in this association was also assessed.Results
The prevalence of obesity increased significantly from baseline to follow-up (p?<?0.0001). In the SEM models, baseline SES had a direct positive effect on changes in BMI (β, 95% CI, 0.02 (0.005 to 0.04), and a direct negative effect on changes in MVPA (β, 95% CI, ??3.81 (??6.92 to ??0.70). Baseline MVPA had a direct negative effect (β, 95% CI, ??0.002 (??0.003 to ??0.0003) and indirect positive effect via change in MVPA (β, 95% CI, 0.01 (0.0001 to 0.001) on change in WC.Conclusions
Our study demonstrates the role and interaction of sociodemographic and behavioural predictors of obesity, and suggests a multifaceted approach to management of the crisis in communities of ageing urban African women.970.