Neighborhood Diversity Research Articles

A Note on Coloring $$(4K_1, C_4, C_6)$$-Free Graphs with a $$C_7$$

Even-hole-free graphs are a graph class of much interest. Foley et al. (Graphs Comb. 36(1):125–138, 2020) have recently studied \((4K_1, C_4, C_6)\)-free graphs, which form a subclass of even-hole-free graphs. Specifically, Foley et al. have shown an algorithm for coloring these graphs via bounded clique-width if they contain a \(C_7\). In this note, we give a simpler and much faster algorithm via a more restrictive graph parameter, neighborhood diversity.

Racism Experience Among American Adults During COVID-19: A Mixed-Methods Study.

Purpose:Despite escalating racism in the United States during COVID-19, few studies have identified correlates of racism experience among Americans using nationally representative data. This study seeks to quantitatively identify correlates of racism experience and qualitatively categorize racism experience and its coping using nationally representative survey data.Methods:Based on data from the “Health, Ethnicity and Pandemic Survey” (N=2,506), a nationally representative survey conducted in October 2020, multivariable logistic regression was estimated to examine the association between self-reported racism experience and selected correlates. Thematic analysis was conducted to qualitatively classify types of racism experience and related coping strategies.Results:When asked whether they had been discriminated or unfairly treated during COVID-19 because of their racial/ethnic background, 19% non-Hispanic Asian and Black respondents said yes, followed by 15% among Hispanics and 3% among non-Hispanic Whites. Besides significant correlates of racism experience identified at the individual and household level, three contextual factors at the neighborhood or state level were associated with lower odds of racism experience, including living in a blue state (adjusted odds ratio [AOR]=0.69, 95% confidence interval [CI]: 0.50–0.95; reference category: red state), living in the top third of the neighborhoods in the sample in terms of racial diversity (AOR=0.65%, 95% CI: 0.42–0.99; reference: bottom third), and coming from neighborhoods with a median population age of 35–39 (AOR=0.67, 95% CI: 0.46–0.98; reference: younger than 35). Prevailing coping strategies against experienced racism included social avoidance, direct confrontation, seeking social and religious support, resorting to hobbies for relief, and taking legal actions.Conclusion:Racism experience is not only correlated with factors at individual level, it is also associated with contextual factors such as political climate, neighborhood diversity, and population age structure. Future efforts in supporting victims of racism might be more cost-effective by focusing on the identified vulnerable groups and related contextual factors.

Neighborhood dissimilarity consistently attenuates competition stress on tree growth under altered water availability in a natural boreal forest

Tree growth regulates forest productivity and carbon sequestration. Although there has been evidence showing positive effects of neighborhood diversity on tree growth, few have experimentally demonstrated how tree growth may respond to neighborhood diversity in natural forests under altered water availability, which is anticipated to occur more frequently with ongoing global climate change. We examined three-year individual tree basal area growth under the water alteration treatments of reduced (-25% throughfall during the growing season), ambient and added (+25% throughfall during the growing season) rainfall in the broadleaf stands, conifer stands and their mixtures of a young natural boreal forest. We quantified neighborhood drought tolerance dissimilarity, phylogeny dissimilarity and neighborhood crowding based on individual tree sizes and the distance between them. We found that the tree growth on average did not change significantly with water alteration but decreased with neighborhood crowding, with the negative crowding effect being more pronounced in water reduction treatment than in ambient and water addition treatments. Higher neighborhood dissimilarity of drought tolerance and phylogeny promoted tree growth consistently across all water conditions. Moreover, the positive effects of neighborhood dissimilarity of drought tolerance and phylogeny became more pronounced with increasing neighborhood crowding. Our results suggest that promoting species mixtures in boreal forests may sustain higher boreal forest productivity under changing water availability.

Perceived diversity, threat, and attitudes towards immigrants: the mitigating role of cross-group friendships and empathy

Little is known about whether the benefits of intergroup contact extend to contexts (e.g., a diverse underdeveloped township) likely to prove demanding for improved intergroup relations. There is a need for further research in these contexts on the potential inhibitors of contact (such as diversity and threat) and their effects. Perceived social diversity has been implicated in the deterioration of intergroup relations. This is particularly salient in the context of immigrant relations, where anti-immigrant sentiments are characterized by perceived threat and lower outgroup trust. Diversity can, however, have an indirect positive effect on outgroup attitudes, via intergroup contact, which reliably predicts lower perceived threat and prejudice. Moreover, recent evidence suggests that empathy could mitigate negative attitudes towards immigrants. We investigated the relationship between perceived neighbourhood diversity, cross-group friendships, realistic and symbolic threat, empathic responding, trust, and outgroup orientation within the volatile context of Black (African) South Africans’ relations with African immigrants. Survey data were collected from South Africans ( N = 317) living in a township. Structural equation modelling showed that perceived diversity was significantly positively associated with both realistic threat (which was significantly negatively associated with outgroup trust) and cross-group friendships (which was significantly negatively associated with realistic threat). There was a significant indirect association between cross-group friendships and positive orientation towards African immigrants via empathic responding towards African immigrants. These findings suggest that cross-group friendships and empathy might mitigate the negative impact of diversity and threat on attitudes towards immigrants, even in this demanding context.

Antecedents of positive and negative intergroup contact: Evidence from a diary study.

In our current globalised, multicultural world, understanding antecedents of reciprocal interactions between native people and people of immigrant background is a major issue, because intergroup contact plays a crucial role in building inclusive societies. In this vein, using daily diary data, we examined the relation between the number of daily positive and negative interactions of White British majority (N=744) and Asian British minority people (N=582) with members of the respective outgroup, with RWA, SDO, perceived ingroup norms, neighbourhood diversity and contextual deprivation. Results showed that for the majority group, ingroup norms in favour of intergroup contact were positively associated with positive intergroup encounters, whereas Right Wing Authoritarianism (RWA) was positively associated with negative intergroup contact. Neighbourhood diversity was positively associated with positive and negative intergroup encounters. Moreover, RWA moderated the relationship between neighbourhood diversity and both positive and negative contact of White British people. For the minority group, ingroup norms were positively associated with positive intergroup contact, and the relationship between ingroup norms and negative contact was moderated by SDO. Overall, different factors affect positive and negative intergroup contact of majority and minority groups. We discuss the implications of the findings for future research and interventions.

Target Set Selection in Dense Graph Classes

In this paper, we study the Target Set Selection problem from a parameterized complexity perspective. Here for a given graph and a threshold for each vertex, the task is to find a set of vertices (called a target set) that activates the whole graph during the following iterative process. A vertex outside the active set becomes active if the number of so far activated vertices in its neighborhood is at least its threshold. We give two parameterized algorithms for a special case where each vertex has the threshold set to half of its neighbors (the so-called Majority Target Set Selection problem) for parameterizations by the neighborhood diversity and the twin cover number of the input graph. We complement these results from the negative side. We give a hardness proof for the Majority Target Set Selection problem when parameterized by (a restriction of) the modular-width---a natural generalization of both previous structural parameters. We also show the Target Set Selection problem parameterized by the neighborhood diversity or by the twin cover number is \sf W[1]-hard when there is no restriction on the thresholds.

Intergroup Contacts, Neighborhood Diversity, and Community Trust: the Asymmetrical Impact of Negative and Positive Experiences

Intergroup contacts can occur in many different places but are often studied only limited to a specific context. This study contributes with data that taps intergroup contacts that occur in both the private and the public sphere, using data from a large-scale survey directed towards individuals nested within 36 different municipalities and over 1,250 different neighborhoods with varying levels of visible minorities. The results also showed that just using the mere frequency of intergroup contacts is not sufficient to understand its association with community trust. Intergroup contacts that occurred in the neighborhood and in civil society organizations had a statistically significant association with community trust, while intergroup contacts that occurred in schools/workplaces and at home did not. The results also indicated that the neighborhood context moderated the impact of intergroup contacts. Whether contacts generated negative experiences mattered. Negative experiences mattered more for community trust especially for those who lived in diverse neighborhoods. The results indicated an asymmetry between the importance of positive and negative experiences of intergroup contacts for community trust.

Parameterized complexity of satisfactory partition problem

Given an undirected graph G, we study the Satisfactory Partition problem, where the goal is to decide whether it is possible to partition the vertex set of G into two parts such that each vertex has at least as many neighbours in its own part as in the other part. The Balanced Satisfactory Partition problem is a variant of the above problem where the two partite sets are required to have the same cardinality. Both problems are known to be NP-complete. This problem was introduced by Gerber and Kobler (2000) [9] and further studied by other authors, but its parameterized complexity remains open until now. We enhance our understanding of the problem from the viewpoint of parameterized complexity. The main results of the paper are the following: (1) Satisfactory Partition is polynomial-time solvable for block graphs, (2) Satisfactory Partition and Balanced Satisfactory Partition are fixed parameter tractable (FPT) when parameterized by neighbourhood diversity. (3) Satisfactory Partition and its balanced version can be solved in polynomial time for graphs of bounded clique-width, and (4) Balanced Satisfactory Partition is W[1]-hard when parameterized by treewidth.

Persistent racial diversity in neighborhoods: what explains it and what are the long-term consequences?

ABSTRACT We explore neighborhoods in Southern California from 1980 to 2010 that exhibit persistent racial diversity (PRD) and the consequences of this PRD. Initial exploratory analyses show that the racial composition of the area surrounding the neighborhood in 1980 is associated with which neighborhoods become PRDs. Our primary analyses compare how PRD neighborhoods change over time (1980–2010) based on several socio-demographic measures to a matched group of non-PRD neighborhoods that had similar characteristics in 1980. The key finding is that PRD neighborhoods improved more on per capita income and percent in poverty compared to their matched tracts from 1980 to 2010. We also found that there was not a single route to persistent diversity, but rather a myriad of pathways through which racial/ethnic diversity can persist over a long time period at the neighborhood level.

Intergroup contacts in civil society organizations and trust: How neighbourhood diversity moderates the role of intergroup contacts

ABSTRACT When dealing with the complex policy issue of how to maintain social cohesion within an increasingly diverse society, decision-makers often view civil society organizations as important actors that can provide opportunities for intergroup contacts and pathways for immigrants to integrate. The present study uses data from a large-scale survey directed toward individuals nested within 36 different local communities and over 1250 different neighbourhoods with varying levels of visible minorities. The results contribute by showing that it is important to consider not only the frequency of intergroup contacts but also the context in which those who are involved in civil society organizations live. Those who are involved in civil society organizations at the local level are embedded in local contexts that moderate how respondents perceive whether others are to be trusted. Very frequent intergroup contacts within civil society organizations correlated more strongly with higher levels of community and outgroup trust among those with native backgrounds who lived in diverse neighbourhoods. Similarly, the results indicated that perceptions of intergroup contact mattered. Neighbourhood diversity and outgroup trust were statistically significant only for those who perceived intergroup contacts to be very positive or rather positive.

Neighborhood diversity structure and neighborhood species richness effects differ across life stages in a subtropical natural secondary forest

Neighborhood diversity structure and neighborhood species richness effects differ across life stages in a subtropical natural secondary forest

Latinx youth's ethnic‐racial identity in context: Examining ethnic‐racial socialization in a new destination area

AbstractThe current study examined how ethnic‐racial socialization (i.e., ERS; cultural socialization, preparation for bias) is shaped by neighborhood characteristics and parents’ perceived discrimination, as well as how ERS shapes youth ethnic‐racial identity (ERI) among Latinx parent‐adolescent dyads (N= 69) living in a new destination area (i.e., not historically settled by Latinx populations). Results showed that neighborhood diversity was positively associated with parents’ ERS beliefs, which in turn were associated with youth's perceptions of parents’ ERS behaviors, which predicted youth ERI outcomes (i.e., centrality and private regard). Neighborhood problems were negatively associated with youth public regard. Neither neighborhood problems nor parents’ perceived discrimination was associated with ERS. The current study adds to limited empirical evidence on how neighborhood structural and social characteristics impact ERS, and in turn, ERI, among Latinx families. Overall, study findings advance knowledge on how cultural and contextual factors shape ERS in an understudied context.

Incidence of syphilis infection and syphilis-related care utilization among adolescents and young adults living with HIV.

Incidence of syphilis has been rising in recent years and disproportionately affects young adults, racial/ethnic minority men, and people living with HIV. This study describes patterns of syphilis infection and syphilis-related care utilization among adolescents and young adults living with HIV (AYALH) in Philadelphia. We conducted a retrospective cohort study of AYALH receiving care at an adolescent-specialty clinic who received a syphilis test and/or benzathine penicillin for syphilis treatment from 2011 to 2018 (N = 335). Syphilis incidence rates were calculated by baseline demographic characteristics and by calendar year. Recurrent survival analysis was used to explore how demographic and neighborhood-level factors were associated with incident syphilis and syphilis-related care utilization. Syphilis-related care was provided 145 times and there were 109 episodes of confirmed syphilis among 83 unique participants between 2011 and 2018. The overall syphilis incidence rate was 13.50 (95% CI: 10.9-16.5) cases per hundred person-years. Participants assigned male sex at birth had higher hazards of infection (HR: 6.12, 95% CI: 1.53-24.48), while older participants (HR: 0.64, 95% CI: 0.58-0.72) and those living further from the clinic had lower hazards of infection (HR: 0.97, 95% CI: 0.94-1.00). Race, insurance status, neighborhood diversity index, and neighborhood social disadvantage index were not associated with hazard of infection or syphilis-related care utilization. Our study found high incidence of syphilis infection among a cohort of AYALH. Integrating comprehensive sexually transmitted infection prevention services into HIV care and improving syphilis prevention services in communities with high syphilis rates should be a priority in future intervention work.

Social capital in the urban context: Diversity and social contacts in Chilean cities

ABSTRACT This study examines the relationship between social capital and neighborhood diversity in Chilean cities. We propose that differences exist between hierarchical forms of diversity, which might erode social trust, and cultural differences that might foster new social links in heterogeneous communities. In Chile, strong material inequalities represent the main form of hierarchical differentiation, while south-to-south immigrants convey qualitative differences based on race, ethnic origin, or cultural practices. In contrast to most Western industrialized countries, where material and ethnic differences tend to converge, they appear to be uncoupled in Chile, explaining the presence of immigrants at different levels of the social hierarchy. We analyze original data from a Latin American country with high domestic inequality. Multilevel models nested at the city level reveal that social capital is negatively correlated with socioeconomic diversity, but positively correlated with immigrant diversity, suggesting that uncoupling these differences has a positive effect on social capital development.

Contrasting Methods of Measurement in Spatial Analyses Examining the Alcohol Environment and Child Maltreatment.

Child physical abuse is a major public health issue in the United States. Environmental child welfare research has focused on neighborhood characteristics and the influence of alcohol and marijuana establishments. To our knowledge, child welfare studies have singularly examined the outcome in terms of victims, that is, at the level of child population, and have not considered the parent population. Thus, in this exploratory study, we use spatial scan statistics to analyze patterns of child physical abuse at the child and household level, and we use Bayesian hierarchical spatial conditional autoregressive models to determine the relative influence of alcohol availability and other environmental factors. We find that household clusters are nested in child clusters and that controlling for alcohol establishments reduces cluster size. In the Bayesian regression models, alcohol availability increased risk slightly, while neighborhood diversity (measured using Blau's Index) elevated risk considerably. Immediate implications for child welfare agencies are discussed.

A spatially explicit index for tree species or trait diversity at neighborhood and stand level

Knowledge about tree species interactions is important for our understanding of forest ecosystems. Research about such interactions requires a quantitative description of different stand mixture types for example with measures of species- or trait-diversity like Simpson- or Rao-diversity. Many currently available diversity measures are based on relative proportions and do not account for the spatial configuration of a stand. They implicitly assume that all trees are equally likely to interact with one another, irrespective of their spatial distance. However, fundamental ecosystem processes such as competition are strongly influenced by intra- or interspecific interactions that take place between neighboring trees.This study introduces a measure for the neighborhood diversity (NDiv) around individual trees by averaging the dissimilarity between a tree and all its neighbors. NDiv uses maps of the ‘area potentially available’ to trees (APA) to define tree neighborhoods. APA-maps are derived by spatially dividing the entire stand area into adjacent patches that approximate the growing space that is potentially available to each tree. The average NDiv of all trees of a stand weighted by the sizes of their APA-patches provides a consistent diversity measure at stand-level. Depending on the used dissimilarity measure, NDiv may either quantify species or trait neighborhood diversity. Species neighborhood diversity and tree height neighborhood diversity of case-study plots were analyzed to demonstrate the application of NDiv.When tree locations were spatially randomized in a simulation study, NDiv of the case-study plots at stand-level was nearly identical to Simpson-diversity. However, the actually observed NDiv of plots with patch-wise mixing of tree species was considerably lower than their Simpson-diversity. On these plots, NDiv accounted for a limited potential for interactions among species since the tree species were growing spatially separated in patches.NDiv is a useful measure of tree diversity when trees are not randomly distributed across a stand and when mixing effects mainly derive from interactions between neighboring trees. The use of NDiv as explanatory variable may help to account for the spatial configuration of trees in forests which may increase the explanatory power of analyses of relationships between tree diversity and ecosystem processes.

Studying Multicultural Diversity of Cities and Neighborhoods through Social Media Language Detection

Cities are growing as melting pots of people with different culture, religion, and language. In this paper, through multilingual analysis of Twitter contents shared within a city, we analyze the prevalent language in the different neighborhoods of the city and we compare the results with census data, in order to highlight any parallelisms or discrepancies between the two data sources. We show that the officially identified neighborhoods are actually representing significantly different communities and that the use of the social media as a data source helps to detect those weak signals that are not captured from traditional data.

Parameterized algorithms for the Happy Set problem

In this paper we study the parameterized complexity for the Maximum Happy Set problem (MaxHS): For an undirected graph G=(V,E) and a subset S⊆V of vertices, a vertex v is happy if v and all its neighbors are in S; otherwise unhappy. Given an undirected graph G=(V,E) and an integer k, the goal of MaxHS is to find a subset S⊆V of k vertices such that the number of happy vertices is maximized. In this paper we first show that MaxHS is W[1]-hard with respect to k even if the input graph is a split graph. Then, we prove the fixed-parameter tractability of MaxHS when parameterized by tree-width, by clique-width plus k, by neighborhood diversity, or by cluster deletion number.

The Small Set Vertex Expansion Problem

In the Small Set Vertex Expansion (SSVE) problem, we are given a graph G=(V,E) and a positive integer k≤|V(G)|2, the goal is to return a set S⊂V(G) of k nodes minimizing the vertex expansion ΦV(S)=|N(S)|. The Small Set Vertex Expansion problem has not been as well studied as its edge-based counterpart Small Set Expansion (SSE). SSE, and SSVE to a less extend, have been studied due to their connection to other hard problems including the Unique Games Conjecture and Graph Colouring. The Small Set Vertex Expansion is known to be NP-complete. We enhance our understanding of the problem from the viewpoint of parameterized complexity by showing that (1) the problem is W[1]-hard when parameterized by the solution size, (2) the problem is fixed-parameter tractable (FPT) when parameterized by the neighbourhood diversity of the input graph, (3) it can be solved in polynomial time for graphs of bounded clique-width, and (4) it is fixed-parameter tractable (FPT) when parameterized by treewidth of the input graph.

COVID-19: A case for the collection of race data in Canada and abroad.

Racialized populations have consistently been shown to have poorer health outcomes worldwide. This pattern has become even more prominent in the wake of the coronavirus disease 2019 (COVID-19) pandemic. In countries where race disaggregated data are routinely collected, such as the United States and the United Kingdom, preliminary reports have identified that racialized populations are at a heightened risk of COVID-19 infection and mortality. Similar patterns are emerging in Canada but rely on proxy measures such as neighbourhood diversity to account for race, in the absence of person-level data. It follows that the collection of race disaggregated data in Canada is a crucial element in identifying individuals at risk of poorer COVID-19 outcomes and developing targeted public health interventions to mitigate risk among Canada's racialized populations. Given this continuing gap, advocating for timely access to this data is of great importance owing to the challenges that the COVID-19 pandemic has highlighted amongst racialized populations in Canada and worldwide.