Latin hypercube sampling with multidimensional uniformity

Complex models can only be realized a limited number of times due to large computational requirements. Methods exist for generating input parameters for model realizations including Monte Carlo simulation (MCS) and Latin hypercube sampling (LHS). Recent algorithms such as maximinLHS seek to maximize the minimum distance between model inputs in the multivariate space. A novel extension of Latin hypercube sampling (LHSMDU) for multivariate models is developed here that increases the multidimensional uniformity of the input parameters through sequential realization elimination. Correlations are considered in the LHSMDU sampling matrix using a Cholesky decomposition of the correlation matrix. Computer code implementing the proposed algorithm supplements this article. A simulation study comparing MCS, LHS, maximinLHS and LHSMDU demonstrates that increased multidimensional uniformity can significantly improve realization efficiency and that LHSMDU is effective for large multivariate problems.     

Turkey’s Twitter public diplomacy: Towards a “new” cult of personality

This study examined how Turkey uses social media as a tool for public diplomacy and how the state’s soft-power efforts have recently changed on the global stage. The researchers constructed a dataset of 2769 Twitter posts by the Turkish government’s most influential public diplomacy accounts. The analyses revealed that the focus of Turkey’s Twitter public diplomacy has become concentrated on the Middle East and North Africa (MENA) region and is thematically focused on the political values embodied by the Turkish president. The findings suggest that public diplomacy remains to be the diplomacy of the government, not of the public, and social media is used as just another tool for propaganda, not as a means of engagement with foreign publics. Further, the findings indicate the emergence of a “new” cult of personality in public diplomacy and point out the instrumental role of social media in changing the dynamics of leader-follower relationship. The study contributes to public relations theory and practice by advancing the burgeoning public diplomacy scholarship at the intersection of social media and relational approaches.     

Trajectories of Interracial Heterosexual Couples: A Longitudinal Analysis of Relationship Quality and Separation

Minimal research has examined interracial couples’ relationship satisfaction and dissolution patterns over time. Using dyadic data across 8 years, we examined potential differences in relationship quality trajectories through latent growth curve modeling with 1,336 couples as well as differential risks for relationship dissolution through logistic regression between same‐race and interracial relationships using a different subset of 2,370 couples. Results indicated that women in interracial relationships were significantly lower in initial relationship quality than women in same‐race relationships. Further, interracial couples of Black‐Hispanic partnerings were twice as likely to separate across 8 years than same‐race couples. These results suggest that despite interracial relationships not substantively differing from same‐race couples in trajectories of relationship quality, specific Black‐Hispanic interracial couples are at a higher risk of eventual separation.     

One does not simply meme about organizations: Exploring the content creation strategies of user-generated memes on Imgur

This study explores how online publics are engaging with organizations by creating and sharing brand-related content online, outside corporate-controlled communication environments. This research employs a quantitative content analysis of memes shared on the social networking site Imgur to reveal how user-generated content conveys meaning about organizations. The analysis reveals brand-centric memes are generally classified as orphan memes, or memes that have distinct textual and visual characteristics separating them from established or emerging meme families. Memes about organizations are neither an overwhelming reflection of biting criticism or support, but rather a reflection of online public engagement with organizations that primarily use humor and textual brand features (or quiddities) to convey their commitment and satisfaction with the organization and unite meme families.     

Trends in bird species richness,abundance and biomass along a tropical urbanization gradient

Impacts of urbanization on biodiversity are commonly studied using urbanization gradients which provide a space-for-time substitution in estimating consequences of urban expansion. Rates of urbanization and human population growth are high in tropical countries of the developing world, which also hold most of the world’s biodiversity hot-spots, yet few studies have considered biodiversity trends along urban gradients in these regions. Bird communities across a gradient of nine sites in Uganda, from the city centre of Kampala to outlying rural locations, were studied over a six year period. These sites were ordered along an urbanization gradient using Principle Components Analysis based on habitat variables estimated at each site. Bird species richness showed a decrease from rural to urban sites, a trend especially evident in forest birds. There was no clear pattern in total abundance, total biomass or biomass per individual along the gradient. However, this latter result was heavily influenced by a colony of Marabou Storks at one site. When this species was omitted, there was evidence of a positive trend with urbanization, showing that as species richness decreased, the bird community was increasingly dominated by larger species with increasing urbanization, which were mainly scavengers able to exploit human refuse. These results provide further support for the negative impacts of urbanization on species richness, but also demonstrate trends in abundance and biomass are variable across different regions. In particular, the increasing dominance of larger species in urban areas may be relevant to certain geographic and/or socioeconomic contexts.     

The Dyadic Effects of Supportive Coparenting and Parental Stress on Relationship Quality Across the Transition to Parenthood

The transition to first‐time parenthood can be challenging for couples. Using a sample of 848 ethnically diverse couples from the Fragile Families and Child Wellbeing Study across the first 3 years of parenthood, we investigated the longitudinal and dyadic associations of each parents’ parental stress, supportive coparenting, and relationship quality. Results from an actor–partner interdependence model indicated that supportive coparenting significantly predicted higher relationship quality for both mothers and fathers. Fathers’ supportive coparenting significantly buffered the effects of mothers’ parental stress on relationship quality. Also, the unique dyadic contexts of each parents’ supportive coparenting, and also both partners’ parental stress were significantly associated with relationship quality. Clinical implications from these findings are discussed through commonly used clinical theories.     

The last mile of the way: understanding caregiving in African American families at the end-of-life

This research is based on in-depth ethnographic interviews and focus groups with 88 African American family caregivers from various regions of the United States during a stressful time in their family development--caregiving at the end-of-life--and the grieving during the aftermath. The study employed a stratified purposeful sampling strategy. Subjects were African Americans from the Northern, Southern, and Midwestern United States. Formal care is complicated by the distrust that many African Americans hold toward the health care system, which has resulted from years of exclusion, racism and discrimination. The findings highlight the importance of hearing from African American families to gain an understanding of what services, including family therapy and other psychotherapy, they will need during this process.