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Urban overheating, driven by global climate change and urban development, is a major contemporary challenge that substantially impacts urban livability and sustainability. Overheating represents a multifaceted threat to the well‐being, performance, and health of individuals as well as the energy efficiency and economy of cities, and it is influenced by complex interactions between building, city, and global scale climates. In recent decades, extensive discipline‐specific research has characterized urban heat and assessed its implications on human life, including ongoing efforts to bridge neighboring disciplines. The research horizon now encompasses complex problems involving a wide range of disciplines, and therefore comprehensive and integrated assessments are needed that address such interdisciplinarity. Here, our objective is to go beyond a review of existing literature and instead provide a broad overview and integrated assessments of urban overheating, defining holistic pathways for addressing the impacts on human life. We (a) detail the characterization of heat hazards and exposure across different scales and in various disciplines, (b) identify individual sensitivities to urban overheating that increase vulnerability and cause adverse impacts in different populations, (c) elaborate on adaptive capacities that individuals and cities can adopt, (d) document the impacts of urban overheating on health and energy, and (e) discuss frontiers of theoretical and applied urban climatology, built environment design, and governance toward reduction of heat exposure and vulnerability at various scales. The most critical challenges in future research and application are identified, targeting both the gaps and the need for greater integration in overheating assessments. Plain Language Summary Many major cities are faced with the compounding effects of climate change and rapid urbanization. One of the main challenges that result is urban overheating, which leads to negative impacts on human life (deteriorating health, productivity, and well‐being) and urban energy systems. Heat exposure in cities, however, is only the trigger and there are other factors that influence impacts. Urban heat vulnerability exists when sensitive people and infrastructure are exposed to extreme heat, and negative impacts ensue if there is a lack of capacity to respond and adapt. Accordingly, to combat overheating challenges, it is critical that multidisciplinary solutions are integrated to mitigate exposure, reduce sensitivity, and increase adaptive capacities. This paper provides an integrated assessment of urban overheating literature, defining pathways for addressing the impacts on human life. We review the state‐of‐the‐art methods used to quantify heat hazards and exposure, detail the sensitivity of people and infrastructure to overheating, and elaborate on the adaptive capacities that individuals and cities can undertake in response. We provide recommendations for both researchers and policymakers that will minimize overheating impacts. These recommendations range from modifications to urban and building design to engaging citizens and informing urban overheating governance. Key Points Urban overheating is the exceedance of locally‐defined thermal thresholds that lead to negative impacts on people and urban systems Exposure to heat hazards compounded with sensitivity and reduced adaptive capacity of people and urban systems lead to increased risk levels Research and application should provide integrated solutions to mitigate exposure, reduce sensitivity, and increase adaptive capacities

Lake charr Salvelinus namaycush are endemic to the formerly glaciated regions of North America and spawn primarily in lakes, unlike most other Salmoninae. Spawning habitats for lake charr are thought to be characterized by relatively large substrate particle sizes which provide sufficient interstitial spaces for egg incubation, but little is known about the physical processes that create or maintain suitable habitats. We review the literature on lake charr spawning habitat and present a conceptual framework that examines the roles of physical variables in creating the appropriate conditions for egg incubation. A critical underlying assumption of this framework is that lake charr will select spawning habitats that provide suitable hypolentic flows for egg incubation. We suggest that the characterization of lakebed surface roughness, current patterns, substrate particle size, and groundwater flows at multiple spatial scales may yield significant insight into the physical mechanisms supporting lacustrine spawning habitats for lake charr and will be useful in creating predictive models of these habitats. This framework may also apply to other lake-spawning lithophilic fish species.

Summer daytime cooling efficiency of various land cover is investigated for the urban core of Phoenix, Arizona, using the Local-Scale Urban Meteorological Parameterization Scheme (LUMPS). We examined the urban energy balance for 2 summer days in 2005 to analyze the daytime cooling-water use tradeoff and the timing of sensible heat reversal at night. The plausibility of the LUMPS model results was tested using remotely sensed surface temperatures from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) imagery and reference evapotranspiration values from a meteorological station. Cooling efficiency was derived from sensible and latent heat flux differences. The time when the sensible heat flux turns negative (sensible heat flux transition) was calculated from LUMPS simulated hourly fluxes. Results indicate that the time when the sensible heat flux changes direction at night is strongly influenced by the heat storage capacity of different land cover types and by the amount of vegetation. Higher heat storage delayed the transition up to 3 h in the study area, while vegetation expedited the sensible heat reversal by 2 h. Cooling efficiency index results suggest that overall, the Phoenix urban core is slightly more efficient at cooling than the desert, but efficiencies do not increase much with wet fractions higher than 20%. Industrial sites with high impervious surface cover and low wet fraction have negative cooling efficiencies. Findings indicate that drier neighborhoods with heterogeneous land uses are the most efficient landscapes in balancing cooling and water use in Phoenix. However, further factors such as energy use and human vulnerability to extreme heat have to be considered in the cooling-water use tradeoff, especially under the uncertainties of future climate change.

Realized thermal niche and habitat use are two conceptualizations of fish habitat based on organismal performance or lake-specific ecology, respectively. Both habitat types were compared for lake trout (Salvelinus namaycush) and brook trout (S. fontinalis) co-occurring in four large (> 500 ha) oligotrophic lakes. Lakes were partitioned into two morphological categories based on possession of a central or non-central deep basin with corresponding differences in adjoining shelf areas. Lake asymmetry in basin location has been shown to strongly influence food web connections based on isolation of basins from shelf areas. Generally, overlap between both habitat types occurred in several comparisons with lake trout, suggesting that thermal habitat is a reasonable proxy for habitat use boundaries though not a full replacement for insights gained from habitat use models. For brook trout, overlap was not as consistent especially for lakes with non-central basins. In central basin lakes, there was closer proximity between the two species and overlap in both thermal niche and habitat use models. There was very limited overlap of either habitat type in lakes with non-central basins. Further, there was no shared areas of interspecific overlap between thermal niche and habitat use in non-central basins pointing to additional complexity governing habitat partitioning between lake trout and brook trout in these types of lakes. The shelf area effect on spatial structure of habitat, and likely food web connections, can occur in lakes regardless of basin centrality so long as shelf areas are large. In this lake set, lakes were sufficiently large to observe this phenomenon.

We report on a management experiment examining the effects of large-scale egg oiling on double-crested cormorant nest abundance and measures of seasonal cormorant density (bird-days/km²) from 2000 to 2005. We employed the staircase design to distinguish transient responses to management treatments from site and year effects that generally contribute to variation in populations. The response to egg oiling in Georgian Bay was as expected with a decline in nest abundance attributable to egg oiling. In the North Channel, nest abundance did not decline because of egg oiling but increased, reflecting either retention of nesting adults or recruitment to colonies. This surprising outcome may stem from fish escapement from pen rearing facilities in the vicinity of the oiling experiment in the North Channel. We observed no effect of egg oiling on the July-August seasonal density of cormorants. The strongest effect size was associated with site effects followed by year effects for nest abundance and seasonal density. The effect size of egg oiling on variation in nest abundance did not exceed 5% for any year in both the North Channel and Georgian Bay. Fish pen culture appears to affect coastal distribution of cormorants.

The immunomodulatory effects of the CCR5-antagonist maraviroc might be beneficial in patients with a suboptimal immunological response, but results of different cART (combination antiretroviral therapy) intensification studies are conflicting. Therefore, we performed a 48-week placebo-controlled trial to determine the effect of maraviroc intensification on CD4+ T-cell counts and immune activation in these patients. Double-blind, placebo-controlled, randomized trial. Major inclusion criteria were 1. CD4+ T-cell count <350 cells/μL while at least two years on cART or CD4+ T-cell count <200 cells/μL while at least one year on cART, and 2. viral suppression for at least the previous 6 months. HIV-infected patients were randomized to add maraviroc (41 patients) or placebo (44 patients) to their cART regimen for 48 weeks. Changes in CD4+ T-cell counts (primary endpoint) and other immunological parameters were modeled using linear mixed effects models. No significant differences for the modelled increase in CD4+ T-cell count (placebo 15.3 CD4+ T cells/μL (95% confidence interval (CI) [1.0, 29.5] versus maraviroc arm 22.9 CD4+ T cells/μL (95% CI [7.4, 38.5] p = 0.51) or alterations in the expression of markers for T-cell activation, proliferation and microbial translocation were found between the arms. However, maraviroc intensification did increase the percentage of CCR5 expressing CD4+ and CD8+ T-cells, and the plasma levels of the CCR5 ligand MIP-1β. In contrast, the percentage of ex-vivo apoptotic CD8+ and CD4+ T-cells decreased in the maraviroc arm. Maraviroc intensification of cART did not increase CD4+ T-cell restoration or decrease immune activation as compared to placebo. However, ex-vivo T-cell apoptosis was decreased in the maraviroc arm. ClinicalTrials.gov NCT00875368.

Locations of potential spawning areas for lake trout (Salvelinus namaycush) were predicted in Lake Opeongo, Ontario, Canada using information gained via acoustic telemetry and geographic information system (GIS) technologies. From 1998 to 2000, 18 adult lake trout (mean fork length 553 mm) implanted with acoustic transmitters (battery life 2 years) were manually tracked. For evening fall locations within the erosive zone of the lake (determined using an existing sedimentation model), habitat variables (slope, depth, and effective fetch) were summarised using GIS. Sites selected by lake trout during the spawning window were in areas of mean fetch equal to 1.5 km and mean slope of 10.6% (n = 50 fixes). We used GIS to identify areas that matched the mean habitat criteria and thus locate potential spawning areas. This model correctly identified 19 of 21 known spawning sites, as well as additional sites used by spawning females in an earlier telemetry study. Depths of traditional fall netting sites are shallow compared to areas in which telemetered lake trout were found during evenings of the spawning period (means 3.1 vs. 5.1 m, respectively). Through the use of information on spawning habitat selection gained through telemetry and knowledge of the physical characteristics of the lake, we provide an alternative means of identifying potential spawning habitat for lake trout.[PUBLICATION ABSTRACT]

This thesis explores the use of hydroacoustic sampling methods to assess the abundance and distribution of lake trout in a single lake. Chapter One focuses upon the development of a target-strength to fish-length relationship for lake trout at a frequency of 120 kHz. A significant and positive relationship was found between target-strength and length (TS = 20 log10 (TLEN) − 65.3) which is comparable to relationships found for other physostomous species of fish. The second chapter applies this relationship to data from monthly acoustic surveys conducted from June–September on a lake trout lake for which mark-recapture population estimates of lake trout are available. Abundance estimates calculated from July, August and September surveys compared favourably to each other and to mark-recapture population estimates. The results of this study suggest that more work is required to determine an optimal sampling season and the sampling intensity required to obtain more precise abundance estimates.

Background Due to their central position in the modern food system, food stores present a unique opportunity to promote healthy dietary behaviour. However, there is a lack of insight into the factors that impede or enhance the implementation of nutritional interventions in food stores. We applied a systems innovation and implementation science framework to the identification of such barriers and facilitators. Methods We conducted a systematic literature review. A search string was developed to identify qualitative and quantitative articles on environmental nutritional interventions in the food store. Four databases were systematically searched for studies published between 2000 and 2018. Eligible publications described study designs or original studies, focused on stimulating healthier dietary behaviour through environmental changes in retail settings and contained information on the perceptions or experiences of retailers or interventionists regarding the implementation process of the intervention. Context-descriptive data was extracted and a quality assessment was performed. Results We included 41 articles, of which the majority was conducted in the USA and involved single stores or a mix of single and multi-store organisations. We categorized barriers and facilitators into 18 themes, under five domains. In the ‘outer setting’ domain, most factors related to consumers’ preferences and demands, and the challenge of establishing a supply of healthy products. In the ‘inner setting’ domain, these related to conflicting values regarding health promotion and commercial viability, store lay-out, (insufficient) knowledge and work capacity, and routines regarding waste avoidance and product stocking. In the ‘actors’ domain, no major themes were found. For the ‘intervention ‘domain’, most related to intervention-context fit, money and resource provision, material quality, and the trade-offs between commercial costs and risks versus commercial and health benefits. For the ‘process’ domain, most factors related to continuous engagement and strong relationships. Conclusions This review provides a comprehensive overview of barriers and facilitators to be taken into account when implementing nutritional interventions in food stores. Furthermore, we propose a novel perspective on implementation as the alignment of intervention and retail interests, and a corresponding approach to intervention design which may help avoid barriers, and leverage facilitators. Trial registration PROSPERO; CRD42018095317 .

Background Food-retail environments are often dominated by unhealthy products, which facilitates unhealthy diets. Limited insight into the factors in the commercial food system that cause this issue makes effective health interventions in retail settings difficult. This study explores the factors and dynamics of the Dutch commercial food system that determine the availability of healthy and unhealthy food in Dutch supermarkets. Methods The study developed and analysed a causal loop diagram (CLD) of the factors and dynamics that determine in-store food availability. Data was collected through semi-structured interviews with food system professionals ( n  = 14) and a focus group with academic experts ( n  = 6), based on the leading question ‘what determines the in-store availability of a product?’ Transcripts were qualitatively coded to identify factors and their interactions. These were visualised in a CLD and subsequently examined to identify causal loops and other dynamics. Results The CLD revealed a core feedback loop between in-store product availability, sales, and pricing, and how this interacted with consumer behaviour and production and supply. Products that sell well and have large profit margins are made more available. Consumers generally buy products that are tasty and affordable, while products with low production and supply costs have better profit margins. These factors favour abundant availability of products consisting of cheap and highly palatable unhealthy ingredients, leading to a reinforcing feedback loop that disadvantages availability of more costly and perishable healthy products. Competition and innovation further emphasise this dynamic, as producers strive to reduce costs and increase palatability in a race to the bottom. Societal interest in health presents a minor feedback loop that favours healthy products due to their positive public image. Conclusions Our findings show that the prevalence of unhealthy products compared to healthy ones is deeply ingrained in the current system dynamics. Policy recommendations include facilitating sustainable corporate governance models, adjusting financial incentives via taxes and subsidies, and enforcing a ‘level playing field’ for healthier business practices.