Neighborhood Diversity Research Articles

The contingency of neighbourhood diversity: Variation of social context using mobile phone application data

This research uses high-density anonymised mobile phone application (MPA) global-positioning system (GPS) data to describe exposure to racial diversity in different social contexts with an aim to clarify the mechanism linking residential diversity to opportunities for diverse social interactions. In particular, it explores the hypothesis that a diverse residential context does not lead to diverse social contact by comparing three exposure measures – residential, observed and interaction – on the census block group level in Chicago. In doing so, it also explores the contribution of activity spaces to opportunities for diverse social contact. The findings show that the exposure to opportunities for diverse social contact measured by MPA data is generally higher than what is implied by residential census data, especially in areas of high residential segregation in the city. Further, measures using MPA data reveal more spatiotemporal heterogeneity of exposure than that implied by the residential context.

Effects of local neighbourhood diversity on crown structure and productivity of individual trees in mature mixed-species forests

BackgroundSpecies-specific genotypic features, local neighbourhood interactions and resource supply strongly influence the tree stature and growth rate. In mixed-species forests, diversity-mediated biomass allocation has been suggested to be a fundamental mechanism underlying the positive biodiversity-productivity relationships. Empirical evidence, however, is rare about the impact of local neighbourhood diversity on tree characteristics analysed at a very high level of detail. To address this issue we analysed these effects on the individual-tree crown architecture and tree productivity in a mature mixed forest in northern Germany.MethodsOur analysis considers multiple target tree species across a local neighbourhood species richness gradient ranging from 1 to 4. We applied terrestrial laser scanning to quantify a large number of individual mature trees (N = 920) at very high accuracy. We evaluated two different neighbour inclusion approaches by analysing both a fixed radius selection procedure and a selection based on overlapping crowns.Results and conclusionsWe show that local neighbourhood species diversity significantly increases crown dimension and wood volume of target trees. Moreover, we found a size-dependency of diversity effects on tree productivity (basal area and wood volume increment) with positive effects for large-sized trees (diameter at breast height (DBH) > 40 cm) and negative effects for small-sized (DBH < 40 cm) trees. In our analysis, the neighbour inclusion approach has a significant impact on the outcome. For scientific studies and the validation of growth models we recommend a neighbour selection by overlapping crowns, because this seems to be the relevant scale at which local neighbourhood interactions occur. Because local neighbourhood diversity promotes individual-tree productivity in mature European mixed-species forests, we conclude that a small-scale species mixture should be considered in management plans.

Rainbow independent sets on dense graph classes

Given a family I of independent sets in a graph, a rainbow independent set is an independent set I such that there is an injection ϕ:I→I where for each v∈I, v is contained in ϕ(v). Aharoni et al. (2019) determined for various graph classes C whether C satisfies a property that for every n, there exists N=N(C,n) such that every family of N independent sets of size n in a graph in C contains a rainbow independent set of size n. In this paper, we add two dense graph classes satisfying this property, namely, the class of graphs of bounded neighborhood diversity and the class of r-powers of graphs in a bounded expansion class.

Diversity and local business structure in European urban contexts

This article investigates the interconnectedness between neighbourhood diversity and local business structures. For this purpose, interviews with residents and entrepreneurs were conducted in three European cities: Budapest, Copenhagen, and Milan. The results show that diversity in the economic structure of urban neighbourhoods is equally important with regards to residents’ quality of life, the image of the neighbourhood, and local social cohesion. Therefore, the main recommendation is that policy makers should act to preserve the diversity of local business structures, and that the concept of diversity itself should be understood in a broader sense, taking local peculiarities into account.

Economic hardship and neighborhood diversity: Influences on consumer well‐being

AbstractResidential neighborhoods shape consumers' well‐being in many profound ways. However, research has yet to adequately understand how consumers' perceived economic hardship interact with neighborhood's income and diversity to influence well‐being. We examine these effects in a diverse and densely populated Asian country of Singapore using four measures of well‐being: perceived quality of life, emotional well‐being, status consciousness, and consumer needs satisfaction. Results from a national sample of 1,445 respondents showed that consumers that were female rather than male, of immigrant origin rather than native born, representing an ethnic minority background, or had fewer economic challenges reported higher well‐being. The relation between economic hardship and consumer well‐being was moderated by neighborhood‐level socioeconomic status (SES) and diversity, such that more economic hardship predicted lower well‐being but only among residents in low SES or heterogeneous neighborhoods. Findings build on social comparison theory, and implications for consumer welfare and marketing practice are provided.

Spatial Heterogeneity of Plant Diversity within and between Neighborhoods and Its Implications for a Plant Diversity Survey in Urban Areas

The spatial heterogeneity of plant diversity at the neighborhood scale has less been understood, although it is very important for the planning and management of neighborhood landscape. In this case study of Beijing, we conducted intensive investigations of the plant diversity in different neighborhoods along a rural–urban gradient. The results showed that the mean numbers of plant species per neighborhood were 30.5 for trees, 18.8 for shrubs, and 31.9 for herbs, respectively. There were significant logarithmic relationships between the numbers of species and patch area, indicating that larger patches within neighborhoods could harbor more plant species. Hierarchical linear modeling showed that the variations in plant diversity within neighborhoods were higher than those between neighborhoods. The number of species increased logistically with both the number of patches within neighborhoods and the number of neighborhoods, suggesting that it is important to sample a sufficient number of patches within neighborhoods, as well as a sufficient number of neighborhoods in order to sample 90% of the plant species during the investigation of plant diversity in urban neighborhoods. So the hierarchical design of sampling should be recommended for investigating plant diversity in urban areas.

Parameterized complexity of fair feedback vertex set problem

Given a graph G=(V,E), a subset S⊆V(G) is said to be a feedback vertex set of G if G−S is a forest. In the Feedback Vertex Set (FVS) problem, we are given an undirected graph G, and a positive integer k, the question is whether there exists a feedback vertex set of size at most k. In this paper, we study three variants of the FVS problem: Unrestricted Fair FVS, Restricted Fair FVS, and Relaxed Fair FVS. In Unrestricted Fair FVS, we are given a graph G and a positive integer ℓ, the question is does there exist a feedback vertex set S⊆V(G) (of any size) such that for every vertex v∈V(G), v has at most ℓ neighbours in S. First, we study Unrestricted Fair FVS from different parameterizations such as treewidth, treedepth, and neighbourhood diversity and obtain several results (both tractability and intractability). Next, we study Restricted Fair FVS, where we are also given an integer k in the input and we demand the size of S to be at most k. This problem is trivially NP-complete; we show that Restricted Fair FVS when parameterized by the solution size k and the maximum degree Δ of the graph G, admits a kernel of size O(Δk). Finally, we study the Relaxed Fair FVS problem, where we want that the size of S is at most k and for every vertex v outside S, v has at most ℓ neighbours in S. We give an FPT algorithm for Relaxed Fair FVS problem running in time cknO(1), for a fixed constant c.

Examining measurement equivalency within the Latin American module of the International Civic Competence Study 2009.

The International Civic and Citizenship Education Study (ICCS) studies are intercontinental studies on the civic education of youth from Asia, Europe, and Latin America. Before we engage in comparative studies on youth from different world regions, we must first establish the equivalency of the scales and items within the databases. The purpose of this study was to examine the level of differential functioning on the Attitudes Towards Neighborhood Diversity 10-item scale in the Latin American module within the ICCS 2009 database for youth from Colombia, Guatemala, and Chile. We first examined the unidimensionality of the scale within each country by assessing configural invariance. Of countries that demonstrated at least adequate fit for configural invariance, we proceeded to examine differential functioning at the item and scale levels. Findings demonstrated that configural invariance held for Chile and Guatemala only. While differential functioning was present on nine of the 10 items between Chile and Guatemala, in all cases the amounts were negligible. There was no differential functioning on the overall scale. Whilst equivalency holds for certain countries on certain scales, in other cases it did not. Thus scholars may consider scale refinement methods before making comparative analyses.

Neighborhood effects and environmental variables drive sapling growth in a young subtropical tree plantation

We established a forest biodiversity and ecosystem functioning experiment in southern China by planting 20,480 saplings of eight subtropical tree species in 320 plots in monocultures and mixtures of two, four and eight species to explore the biodiversity-ecosystem functioning (BEF) relationships and the underlying coexistence determinants. In this study, we aimed to report the growth of these planted saplings and explore its abiotic and biotic driving factors. Specifically, we analyzed the relative importance of sapling species identity, initial size, neighborhood interactions, neighborhood diversity, and environmental factors to sapling growth in the early stage of our BEF experiment. We found that the species of Ilex rotunda, Pinus massoniana and Elaeocarpus sylvestris grew much faster than other five species, followed by Castanopsis carlesii, Cinnamomum camphora and Schima superba. Erythrophleum fordii and Castanopsis fissa had the lowest growth rates in ground diameter and height. In addition, the relative growth rates of saplings were positively related to the neighborhood interactions, neighborhood diversity and soil nutrients, but were negatively related to initial size. Our study stresses the importance of better understanding the effects of environmental and local neighborhood conditions on initial growth of subtropical forest tree species in a mixed plantation, and provides reference for other BEF experiments in China and elsewhere.

Neighborhood Diversity and Food Access in a Changing Urban Spatial Structure

This paper examines food access disparity in relation to neighborhood diversity, especially race/ethnicity and poverty in a changing intrametropolitan spatial structure, using the Atlanta Metropolitan Statistical Area (MSA) as a case study. With detailed grocery store data, this study finds a substantive change in food access between 2003 and 2015 in terms of both the number of grocery stores and the gravity–based accessibility indicator, although such access varies by neighborhood characteristics and spatial location in terms of central city, inner–ring suburbs, and outer–ring suburbs. While access to grocery stores for minority–concentrated neighborhoods in outer–ring suburbs is comparable to other neighborhoods, neighborhoods with a high share of African American residents in inner–ring suburbs and those with a high share of Latino residents in the central city have significantly lower access to food outlets. Neighborhoods with higher poverty rate tend to have more food outlets across the region except for in inner–ring suburbs.

A double‐edged sword: How social diversity affects trust in representatives via perceived competence and warmth

AbstractPrevious research has claimed that diversity erodes trust, even though the empirical evidence is mixed and restricted to ethnic neighborhood diversity. Against the backdrop of increasing diversity within the political sphere and concurrently declining political trust, we examined the impact of social diversity on trust in groups of political representatives. In two experiments (N1 = 109, N2 = 248) we tested how the diversity of political parties affected citizens’ trust in them. In line with predictions of the stereotype content model, diverse parties were perceived as warmer and less competent than non‐diverse parties (Experiments 1–2). Additionally, party diversity was perceived as having more benefits, but also involving more threats (Experiment 2). Consequently, diversity had both positive (via warmth and benefits) and negative (via competence and threats) indirect effects on trust. These results help to untangle previously mixed, for the most part non‐experimental, findings of the relationship between diversity and trust.

Spatial super-spreaders and super-susceptibles in human movement networks

As lockdowns and stay-at-home orders start to be lifted across the globe, governments are struggling to establish effective and practical guidelines to reopen their economies. In dense urban environments with people returning to work and public transportation resuming full capacity, enforcing strict social distancing measures will be extremely challenging, if not practically impossible. Governments are thus paying close attention to particular locations that may become the next cluster of disease spreading. Indeed, certain places, like some people, can be “super-spreaders”. Is a bustling train station in a central business district more or less susceptible and vulnerable as compared to teeming bus interchanges in the suburbs? Here, we propose a quantitative and systematic framework to identify spatial super-spreaders and the novel concept of super-susceptibles, i.e. respectively, places most likely to contribute to disease spread or to people contracting it. Our proposed data-analytic framework is based on the daily-aggregated ridership data of public transport in Singapore. By constructing the directed and weighted human movement networks and integrating human flow intensity with two neighborhood diversity metrics, we are able to pinpoint super-spreader and super-susceptible locations. Our results reveal that most super-spreaders are also super-susceptibles and that counterintuitively, busy peripheral bus interchanges are riskier places than crowded central train stations. Our analysis is based on data from Singapore, but can be readily adapted and extended for any other major urban center. It therefore serves as a useful framework for devising targeted and cost-effective preventive measures for urban planning and epidemiological preparedness.

Cultural and economic residential sorting of Auckland’s population, 1991–2013: an entropy approach

Auckland, the largest city of New Zealand, is one of the most diverse cities in the world, with more than 40% of its population born abroad, more than 200 ethnicities represented and 160 languages spoken. In this paper, we measure residential sorting of individuals in Auckland by their cultural (ethnicity) and economic (income, education and occupation) characteristics for the years 1991–2013. Using entropy-based measures of residential sorting and of neighbourhood diversity, we find that individuals exhibit greater residential sorting by ethnicity than by economic characteristics. Geographically, the semi-rural fringes of the city exhibit less diversity than the central urban area. Multi-group indexes of cultural and economic sorting showed a small decline over the 1991–2013 period. We also observe that ethnic sorting declined over that period for broad ethnic groups, but that sorting within the broad ethnic groups increased since 2001. A similar pattern of decreasing sorting at the aggregate level, with increasing sorting within groups in the more recent sub-period, is observed for occupations.

Impact of Invasive Bees on Plant-Pollinator Interactions and Reproductive Success of Plant Species in Mixed Nothofagus antarctica Forests.

Invasive social bees can alter plant-pollinator interactions with detrimental effects on both partners. However, most studies have focused on one invasive bee species, while the interactions among two or more species remain poorly understood. Also, many study sites had a history of invasive bees, being hard to find sites with historical low abundances. In Patagonia, Bombus ruderatus (F.) invasion begun in 1993 and B. terrestris (L.) in 2006. Though honey bees (Apis mellifera L.) introduction started in 1859, their density is still low in some parts. By experimentally increasing honey bee densities, we evaluated the effect of honey bees and bumblebees floral visitation on native pollinator floral visitation, pollen deposition, and reproductive success of three plant species in mixed Nothofagus antarctica forests of northern Patagonia: Oxalis valdiviensis, Mutisia spinosa and Cirsium vulgare. Our results show that exotic bees became the main floral visitors. No negative association was found between invasive bee and native pollinator visitation rates, but there was evidence of potential competition between honey bees and bumblebees. Floral neighborhood diversity played an important role in pollinator behavior. Conspecific pollen deposition was high for all species, while deposition of heterospecific pollen was very high in M. spinosa and C. vulgare. Not as expected, honey bees visitation rate had a negative effect on heterospecific pollen deposition in C. vulgare. For O. valdiviensis, exotic visitation rates increased conspecific pollen deposition, which was positively related to reproductive success. Although exotic bees became main floral visitors, their contribution to reproductive success was only clear for one species.

One+One+One=A lot: The cumulative effect of Israel’s flagship urban renewal policy on neighborhood diversity

• This study examines the effect of Israel’s main urban renewal policy (TAMA 38) on urban diversity. • Sporadic renewal can have a cumulative impact and wreak substantial change (1 + 1+1 = a lot). • TAMA 38 has promoted social and housing diversity in the examined area. • Diversity in the wake of TAMA 38 may be short-lived and is likely to be replaced by segregation. • The findings highlight the importance of a local perspective in urban renewal plans.

Integer programming in parameterized complexity: Five miniatures

Powerful results from the theory of integer programming have recently led to substantial advances in parameterized complexity. However, our perception is that, except for Lenstra’s algorithm for solving integer linear programming in fixed dimension, there is still little understanding in the parameterized complexity community of the strengths and limitations of the available tools. This is understandable: it is often difficult to infer exact runtimes or even the distinction between FPT and XP algorithms, and some knowledge is simply unwritten folklore in a different community. We wish to make a step in remedying this situation. To that end, we first provide an easy to navigate quick reference guide of integer programming algorithms from the perspective of parameterized complexity. Then, we show their applications in three case studies, obtaining FPT algorithms with runtime f(k)poly(n). We focus on: •Modeling: since the algorithmic results follow by applying existing algorithms to new models, we shift the focus from the complexity result to the modeling result, highlighting common patterns and tricks which are used.•Optimality program: after giving an FPT algorithm, we are interested in reducing the dependence on the parameter; we show which algorithms and tricks are often useful for speed-ups.•Minding the poly(n): reducing f(k) often has the unintended consequence of increasing poly(n); so we highlight the common trade-offs and show how to get the best of both worlds. Specifically, we consider graphs of bounded neighborhood diversity which are in a sense the simplest of dense graphs, and we show several FPT algorithms for Capacitated Dominating Set, Sum Coloring, Max-q-Cut, and certain other coloring problems by modeling them as convex programs in fixed dimension, n-fold integer programs, bounded dual treewidth programs, indefinite quadratic programs in fixed dimension, parametric integer programs in fixed dimension, and 2-stage stochastic integer programs.

The average cut-rank of graphs

The cut-rank of a set X of vertices in a graph G is defined as the rank of the X×(V(G)∖X) matrix over the binary field whose (i,j)-entry is 1 if the vertex i in X is adjacent to the vertex j in V(G)∖X and 0 otherwise. We introduce the graph parameter called the average cut-rank of a graph, defined as the expected value of the cut-rank of a random set of vertices. We show that this parameter does not increase when taking vertex-minors of graphs and a class of graphs has bounded average cut-rank if and only if it has bounded neighborhood diversity. This allows us to deduce that for each real α, the list of induced-subgraph-minimal graphs having average cut-rank larger than (or at least) α is finite. We further refine this by providing an upper bound on the size of obstruction and a lower bound on the number of obstructions for average cut-rank at most (or smaller than) α for each real α≥0. Finally, we describe explicitly all graphs of average cut-rank at most 3∕2 and determine up to 3∕2 all possible values that can be realized as the average cut-rank of some graph.

Subgraph Isomorphism on Graph Classes that Exclude a Substructure

We study Subgraph Isomorphism on graph classes defined by a fixed forbidden graph. Although there are several ways for forbidding a graph, we observe that it is reasonable to focus on the minor relation since other well-known relations lead to either trivial or equivalent problems. When the forbidden minor is connected, we present a near dichotomy of the complexity of Subgraph Isomorphism with respect to the forbidden minor, where the only unsettled case is \(P_{5}\), the path of five vertices. We then also consider the general case of possibly disconnected forbidden minors. We show fixed-parameter tractable cases and randomized XP-time solvable cases parameterized by the size of the forbidden minor H. We also show that by slightly generalizing the tractable cases, the problem becomes NP-complete. All unsettle cases are equivalent to \(P_{5}\) or the disjoint union of two \(P_{5}\)’s. As a byproduct, we show that Subgraph Isomorphism is fixed-parameter tractable parameterized by vertex integrity. Using similar techniques, we also observe that Subgraph Isomorphism is fixed-parameter tractable parameterized by neighborhood diversity.

Neighborhood Racial and Ethnic Diversity and Residential Segregation in Large Urban Areas in the U.S., 1980-2010

Racial and ethnic neighborhood diversity and residential segregation among whites, African-Americans, Latinos, and Asians and Pacific Islanders are measured for 59 large urban areas in the United States from 1980 to 2010. Neighborhood diversity is defined as the average of diversity in census tracts. Neighborhood diversity increased dramatically from 1980 to 2010 for nearly all urban areas. It was significantly higher in areas in the South and West and in areas that were growing more rapidly. Residential segregation is defined as the relative difference between neighborhood diversity and the maximum possible for the urban area given the distribution of the population across the racial and ethnic groups. Segregation declined over the period considered and was lowest in urban areas in the West.

Parameterized complexity of happy coloring problems

In a vertex-colored graph, an edge is happy if its endpoints have the same color. Similarly, a vertex is happy if all its incident edges are happy. Motivated by the computation of homophily in social networks, we consider the algorithmic aspects of the following Maximum Happy Edges ( k-MHE ) problem: given a partially k-colored graph G and an integer ℓ, find an extended full k-coloring of G making at least ℓ edges happy. When we want to make ℓ vertices happy on the same input, the problem is known as Maximum Happy Vertices ( k-MHV ). We perform an extensive study into the complexity of the problems, particularly from a parameterized viewpoint. For every k≥3, we prove both problems can be solved in time 2nnO(1). Moreover, by combining this result with a linear vertex kernel of size (k+ℓ) for k-MHE, we show that the edge-variant can be solved in time 2ℓnO(1). In contrast, we prove that the vertex-variant remains W[1]-hard for the natural parameter ℓ. However, the problem does admit a kernel with O(k2ℓ2) vertices for the combined parameter k+ℓ. From a structural perspective, we show both problems are fixed-parameter tractable for treewidth and neighborhood diversity, which can both be seen as sparsity and density measures of a graph. Finally, we extend the known ▪-completeness results of the problems by showing they remain hard on bipartite graphs and split graphs. On the positive side, we show the vertex-variant can be solved optimally in polynomial-time for cographs.