Cause and context: place-based approaches to investigate how environments affect mental health

Objectives Our surroundings affect our mood, our recovery from stress, our behavior, and, ultimately, our mental health. Understanding how our surroundings influence mental health is central to creating healthy cities. However, the traditional observational methods now dominant in the psychiatric epidemiology literature are not sufficient to advance such an understanding. In this essay we consider potential alternative strategies, such as randomizing people to places, randomizing places to change, or harnessing natural experiments that mimic randomized experiments. Methods We discuss the strengths and weaknesses of these methodological approaches with respect to (1) defining the most relevant scale and characteristics of context, (2) disentangling the effects of context from the effects of individuals’ preferences and prior health, and (3) generalizing causal effects beyond the study setting. Results Promising alternative strategies include creating many small-scale randomized place-based trials, using the deployment of place-based changes over time as natural experiments, and using fluctuations in the changes in our surroundings in combination with emerging data collection technologies to better understand how surroundings influence mood, behavior, and mental health. Conclusions Improving existing research strategies will require interdisciplinary partnerships between those specialized in mental health, those advancing new methods for place effects on health, and those who seek to optimize the design of local environments

Knowledge and behavioural interventions to reduce human health risk from private groundwater systems: A global review and pooled analysis based on development status

Groundwater contamination constitutes a significant health risk for private well users residing in rural areas. As the responsibility to safeguard rural private domestic groundwater typically rests with non-expert homeowners, interventions promoting risk mitigation and awareness represent the most viable means of preventing supply contamination. However, no global review or pooled analyses of these interventions has been undertaken to date. The current study sought to identify and quantify the performance of private well interventions from 1990 to 2018 via a global systematised review and pooled analysis. The PICO (Population-Intervention-Comparison-Outcome) approach was employed for literature identification. Relevant studies were statistically analysed across two quantitative outcome (performance) types, namely knowledge and behaviour, controlling for intervention characteristics and country development status. Mean behavioural and knowledge attainment across interventions was 53% and 48%, respectively, with interventions in economically developed regions exhibiting higher behavioural outcomes (56% vs. 45%) than those in developing regions. Geographically, interventions were located in southern or southeast Asia (n = 23), North America (n = 15), Central America (n = 1) and Africa (n = 1), with none identified in Australia/Oceania, Europe, or South America. Behavioural outcomes were significantly associated with presence of educational/research coordinator (p = 0.023), with these interventions attaining higher levels of efficacy (+74%) than those implemented by other coordinator types. Findings indicate that instructor-led, practical interventions allied with both large- and local-scale awareness-raising campaigns represent an optimum approach for future private well risk interventions. Subsequent adoption of such interventions may lead to increased levels of private well maintenance and provide a point of reference for myriad water and health communication contexts

The role of drug resistance in poor viral suppression in rural South Africa: findings from a population-based study.

BACKGROUND:Understanding factors driving virological failure, including the contribution of HIV drug resistance mutations (DRM), is critical to ensuring HIV treatment remains effective. We examine the contribution of drug resistance mutations for low viral suppression in HIV-positive participants in a population-based sero-prevalence survey in rural South Africa. METHODS:We conducted HIV drug resistance genotyping and ART analyte testing on dried blood spots (DBS) from HIV-positive adults participating in a 2014 survey in North West Province. Among those with virologic failure (> 5000 copies/mL), we describe frequency of DRM to protease inhibitors (PI), nucleoside reverse transcriptase inhibitors (NRTI), and non-nucleoside reverse transcriptase inhibitors (NNRTI), report association of resistance with antiretroviral therapy (ART) status, and assess resistance to first and second line therapy. Analyses are weighted to account for sampling design. RESULTS:Overall 170 DBS samples were assayed for viral load and ART analytes; 78.4% of men and 50.0% of women had evidence of virologic failure and were assessed for drug resistance, with successful sequencing of 76/107 samples. We found ≥1 DRM in 22% of participants; 47% were from samples with detectable analyte (efavirenz, nevirapine or lopinavir). Of those with DRM and detectable analyte, 60% showed high-level resistance and reduced predicted virologic response to ≥1 NRTI/NNRTI typically used in first and second-line regimens. CONCLUSIONS:DRM and predicted reduced susceptibility to first and second-line regimens were common among adults with ART exposure in a rural South African population-based sample. Results underscore the importance of ongoing virologic monitoring, regimen optimization and adherence counseling to optimize durable virologic suppression

Statistical Mechanics of Semi-Supervised Clustering in Sparse Graphs

We theoretically study semi-supervised clustering in sparse graphs in the presence of pairwise constraints on the cluster assignments of nodes. We focus on bi-cluster graphs, and study the impact of semi-supervision for varying constraint density and overlap between the clusters. Recent results for unsupervised clustering in sparse graphs indicate that there is a critical ratio of within-cluster and between-cluster connectivities below which clusters cannot be recovered with better than random accuracy. The goal of this paper is to examine the impact of pairwise constraints on the clustering accuracy. Our results suggests that the addition of constraints does not provide automatic improvement over the unsupervised case. When the density of the constraints is sufficiently small, their only impact is to shift the detection threshold while preserving the criticality. Conversely, if the density of (hard) constraints is above the percolation threshold, the criticality is suppressed and the detection threshold disappears.Comment: 8 pages, 4 figure

An injectable bone marrow-like scaffold enhances T cell immunity after hematopoietic stem cell transplantation.

Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment for multiple disorders, but deficiency and dysregulation of T cells limit its utility. Here we report a biomaterial-based scaffold that mimics features of T cell lymphopoiesis in the bone marrow. The bone marrow cryogel (BMC) releases bone morphogenetic protein-2 to recruit stromal cells and presents the Notch ligand Delta-like ligand-4 to facilitate T cell lineage specification of mouse and human hematopoietic progenitor cells. BMCs subcutaneously injected in mice at the time of HSCT enhanced T cell progenitor seeding of the thymus, T cell neogenesis and diversification of the T cell receptor repertoire. Peripheral T cell reconstitution increased ~6-fold in mouse HSCT and ~2-fold in human xenogeneic HSCT. Furthermore, BMCs promoted donor CD4+ regulatory T cell generation and improved survival after allogeneic HSCT. In comparison to adoptive transfer of T cell progenitors, BMCs increased donor chimerism, T cell generation and antigen-specific T cell responses to vaccination. BMCs may provide an off-the-shelf approach for enhancing T cell regeneration and mitigating graft-versus-host disease in HSCT

To what extent can zero tillage lead to a reduction in greenhouse gas emissions from temperate soils?

Soil tillage practices have a profound influence on the physical properties of soil and the greenhouse gas (GHG) balance. However there have been very few integrated studies on the emission of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) and soil biophysical and chemical characteristics under different soil management systems. We recorded a significantly higher net global warming potential under conventional tillage systems (26–31% higher than zero tillage systems). Crucially the 3-D soil pore network, imaged using X-ray Computed Tomography, modified by tillage played a significant role in the flux of CO2 and CH4. In contrast, N2O flux was determined mainly by microbial biomass carbon and soil moisture content. Our work indicates that zero tillage could play a significant role in minimising emissions of GHGs from soils and contribute to efforts to mitigate against climate change

016— Quality of College Students’ Close Peer Relationships

This study compares the quality of different types of college students’ relationships: same-sex (SS) friendships, other-sex (OS) friendships, and romantic relationships. Previous research by Hand and Furman (2009) indicated that adolescents perceived their OS friendships as less supportive than both their SS friendships and romantic relationships. Adolescents also perceived their OS friendships as having less conflict than their romantic relationships. The current study attempts to replicate these findings with college students, who tend to have more time and opportunity to develop close OS friendships. In addition, we examine the power dynamic in these relationships, as well as several factors of each type of relationship, including length of the current relationship and previous experience with each type of relationship