Urbanization impacts the taxonomic and functional structure of aquatic macroinvertebrate communities in a small Neotropical city

Due to habitat fragmentation, resource disruption and pollution, urbanization is one of the most destructive forms of anthropization affecting ecosystems worldwide. Generally, human-mediated perturbations dramatically alter species diversity in urban sites compared to the surroundings, thus influencing the functioning of the entire ecosystem. We investigated the taxonomic and functional diversity patterns of the aquatic macroinvertebrate communities in tank bromeliads by comparing those found in a small Neotropical city with those from an adjacent rural site. Changes in the quality of detrital inputs in relation to lower tree diversity and the presence of synanthropic species are likely important driving forces behind the observed structural changes in the urban site. Leaf-litter processors (i.e., shredders, scrapers) were positively affected in the urban site, while filter-feeders that process smaller particles produced by the activity of the shredders were negatively affected. Because we cannot ascertain whether the decline in filter-feeders is related to food web-mediated effects or to competitive exclusion (Aedes aegypti mosquitoes were present in urban bromeliads only), further studies are necessary to account for the effects of intra-guild competition or inter-guild facilitation.     

Roma and the politics of double discourse in contemporary Europe

ABSTRACT

The article analyses the politics of ‘double discourse’ in relation to Roma that has evolved in contemporary neoliberal Europe. On the one hand, the double discourse promotes the integration, rights and equal opportunities of Roma, on the other, it denies recognition of, and ways to address, enduring structural violence and rising social insecurity. The article argues that the politics of ‘double discourse’, as a neoliberal approach towards Roma, is structured by two contradictory discourses that speak to different audiences, using duplicitous approaches to create anti-Roma consensus and maintain the critical difference and subordinated position of the racialised Romani populations in Europe. By studying the representation of Roma in the cases of so-called 'child theft' in Greece and Ireland, and in the recent ‘refugee crisis’, the paper identifies and discusses three dimensions of contemporary neoliberal double discourse: racialised de-Europeanisation, neoliberal undeservingness and (dis)articulation of citizenship.     

Dynamic heterogeneity: a framework to promote ecological integration and hypothesis generation in urban systems

Urban areas are understood to be extraordinarily spatially heterogeneous. Spatial heterogeneity, and its causes, consequences, and changes, are central to ecological science. The social sciences and urban design and planning professions also include spatial heterogeneity as a key concern. However, urban ecology, as a pursuit that integrates across these disciplines, lacks a theoretical framework that synthesizes the diverse and important aspects of heterogeneity. This paper presents the concept of dynamic heterogeneity as a tool to explore how social and ecological heterogeneities interact and how they together act as both an outcome of past interactions and a driver future heterogeneity and system functions. To accomplish this goal, we relate heterogeneity to the fundamental concept of the human ecosystem. The human ecosystem concept identifies key processes that require operationalized models of dynamic heterogeneity in three process realms: the flow of materials, the assembly of urban ecosystem biota, and the locational choices humans make concerning land. We exemplify a specific dynamic model of heterogeneity in each of these realms, and indicate a range of complementary statistical approaches to integrate the drivers and outcomes of dynamic heterogeneity across the three realms. We synthesize a hierarchical framework for a theory of dynamic urban heterogeneity, noting its complementarity to other major urban theories and general model approaches. We hypothesize that human actions and structures amplify the dynamics of heterogeneity in urban systems.     

Doin’ Meth or Doin’ Math: What Client Constructions of Social Class Mean for Social Work Practice

The voices of people experiencing poverty are underrepresented in social work research, public policy development, and practice interventions. This study explored the social class attributions of clients receiving poverty-related services through qualitative interviews. Findings reveal dynamic contributions of individual, environmental, and structural factors of social class positioning and significant stress and stigmatization associated with experiencing economic hardship. Participants indicate a sense of lived contradiction, viewing social class to be the result of fate while simultaneously endorsing individualistic attributions of poverty. Results have implications for social work research and practice, as well as poverty-related policy and program development.     

Connected political consumers: transforming personalized politics among youth into broader repertoires of action

This study explores political consumerism motivations in an effort to understand the complex ways in which this lifestyle practice fits into the broader participation repertoires of young citizens. We begin by outlining the psychological motivations for political consumerism, and theorize how they might orient political consumers toward (and away from) online expressive, political, and civic participation. In particular, we examine how the desire to gratify distinct psychological needs shapes navigation of the digital media environment in search of information and connection, and how this, in turn, shapes participation. Results of a national survey of young adults show that value-expressive, social-identification, and social-approval motivations for green living relate differently to participation, and that online community embeddedness mediates these relationships. The findings suggest that connecting to likeminded others via digitally-enabled communities can transform individual concerns into collective concerns, and extend participation from the private spheres of everyday life into the public sphere.     

Use of online crowdsourcing platforms for gambling research

Crowdsourcing platforms like Amazon’s Mechnical Turk and Crowdflower have been touted to be a cost-effective way to collect large amounts of behavioural data. Across four large-n studies, gambling-related behaviours, tendencies and traits among participants in these labour markets were examined. In Studies 1 and 2, both conducted on Crowdflower, problem gamblers (as measured by the benchmark Problem Gambling Severity Index) comprised 24.5% and 21.9% of participants, respectively. In Study 3, conducted on Mechanical Turk, problem gamblers comprised 9.0% of participants. In Study 4, a two-wave longitudinal study conducted on Crowdflower, problem gamblers comprised 13.5% of participants in wave one and 14.8% of participants in wave two. In Studies 2 and 3, strong convergent associations were demonstrated across various measures of problem gambling tendencies and general gambling involvement. Furthermore, it was demonstrated that gambling was associated with personality traits (impulsivity, sensation-seeking, self-control), risk attitudes, affect, and behavioural risk-taking consistent with previous research. In Study 4, it was demonstrated that measures of problem gambling have acceptable test-retest reliability. Online crowdsourcing platforms appear to offer access to samples with remarkably high proportions of problem gamblers. However, this characteristic means that such samples are not necessarily representative of gambling tendencies among more general populations.     

Cambodian Refugee Families: Impacts of Immigration-Related Stressors on Intergenerational Relationships

The purpose of this study was to elucidate Cambodian refugees’ perceptions of immigration-related stressors and their impacts on intergenerational relations during the processes of immigration and settlement. We used narrative analysis to evoke older immigrants’ voices as they transitioned to the United States. Thirty-one Cambodian immigrants were interviewed using open-ended interview guides informed by ethnographic tenets of data collection. Participants expressed (a) changes in family structure and elder isolation and (b) intergenerational ambivalence and elder’s dependence on adult children as products of immigration-related stressors. Implications of these results for refugee and immigrant mental health research are discussed.     

Approximate confidence intervals for the weighted kappa coefficient of a binary diagnostic test subject to a case–control design

Case–control design to assess the accuracy of a binary diagnostic test (BDT) is very frequent in clinical practice. This design consists of applying the diagnostic test to all of the individuals in a sample of those who have the disease and in another sample of those who do not have the disease. The sensitivity of the diagnostic test is estimated from the case sample and the specificity is estimated from the control sample. Another parameter which is used to assess the performance of a BDT is the weighted kappa coefficient. The weighted kappa coefficient depends on the sensitivity and specificity of the diagnostic test, on the disease prevalence and on the weighting index. In this article, confidence intervals are studied for the weighted kappa coefficient subject to a case–control design and a method is proposed to calculate the sample sizes to estimate this parameter. The results obtained were applied to a real example.     

A note on the Cauchy-type mixture distributions

An interesting class of continuous distributions, called Cauchy-type mixture, with potential applications in modelling erratic phenomena is introduced by Soltani and Tafakori [A class of continuous kernels and Cauchy type heavy tail distributions. Statist Probab Lett. 2013;83:1018–1027]. In this work, we provide more insights into the Cauchy-type mixture distributions, involving certain characterizations, connections with the generalized Linnik distributions and the class of discrete distributions induced by stable laws. We also prove that the Laplace transform of Cauchy-type mixture distributions when normalized by constant terms become as a density functions in terms of distributional conjugate property.