Educating Engineers to Work Ethically with Global Marginalized Communities.

Ethical reasoning is an important ability for engineers working with marginalized communities in global contexts. However, the ethical awareness and development that are critical for this work may not be included in traditional engineering education. This article presents faculty perspectives on the ethical and societal issues (ESI) that should be taught and the pedagogies that are used to prepare students for development engineering. Among 60 survey respondents who taught courses focused on global and/or development (GD) issues, the ESI topics that were particularly congruent included poverty, sustainability, social justice, and engineering decisions under uncertainty. Faculty interviews highlighted that GD should foreground the human side of engineering, respectful partnerships with communities grounded in an asset perspective, and considerations of historical elements. Discussions, case studies, design, and reflection are impactful pedagogies that can complement learning through service to achieve ESI educational goals.

The worldwide impact of urbanisation on avian functional diversity.

Urbanisation is driving rapid declines in species richness and abundance worldwide, but the general implications for ecosystem function and services remain poorly understood. Here, we integrate global data on bird communities with comprehensive information on traits associated with ecological processes to show that assemblages in highly urbanised environments have substantially different functional composition and 20% less functional diversity on average than surrounding natural habitats. These changes occur without significant decreases in functional dissimilarity between species; instead, they are caused by a decrease in species richness and abundance evenness, leading to declines in functional redundancy. The reconfiguration and decline of native functional diversity in cities are not compensated by the presence of exotic species but are less severe under moderate levels of urbanisation. Thus, urbanisation has substantial negative impacts on functional diversity, potentially resulting in impaired provision of ecosystem services, but these impacts can be reduced by less intensive urbanisation practices.

Theoretical Perspectives of the Baltimore Ecosystem Study: Conceptual Evolution in a Social-Ecological Research Project.

The Earth's population will become more than 80% urban during this century. This threshold is often regarded as sufficient justification for pursuing urban ecology. However, pursuit has primarily focused on building empirical richness, and urban ecology theory is rarely discussed. The Baltimore Ecosystem Study (BES) has been grounded in theory since its inception and its two decades of data collection have stimulated progress toward comprehensive urban theory. Emerging urban ecology theory integrates biology, physical sciences, social sciences, and urban design, probes interdisciplinary frontiers while being founded on textbook disciplinary theories, and accommodates surprising empirical results. Theoretical growth in urban ecology has relied on refined frameworks, increased disciplinary scope, and longevity of interdisciplinary interactions. We describe the theories used by BES initially, and trace ongoing theoretical development that increasingly reflects the hybrid biological-physical-social nature of the Baltimore ecosystem. The specific mix of theories used in Baltimore likely will require modification when applied to other urban areas, but the developmental process, and the key results, will continue to benefit other urban social-ecological research projects.

Global synthesis of the temperature sensitivity of leaf litter breakdown in streams and rivers.

Streams and rivers are important conduits of terrestrially derived carbon (C) to atmospheric and marine reservoirs. Leaf litter breakdown rates are expected to increase as water temperatures rise in response to climate change. The magnitude of increase in breakdown rates is uncertain, given differences in litter quality and microbial and detritivore community responses to temperature, factors that can influence the apparent temperature sensitivity of breakdown and the relative proportion of C lost to the atmosphere vs. stored or transported downstream. Here, we synthesized 1025 records of litter breakdown in streams and rivers to quantify its temperature sensitivity, as measured by the activation energy (Ea , in eV). Temperature sensitivity of litter breakdown varied among twelve plant genera for which Ea could be calculated. Higher values of Ea were correlated with lower-quality litter, but these correlations were influenced by a single, N-fixing genus (Alnus). Ea values converged when genera were classified into three breakdown rate categories, potentially due to continual water availability in streams and rivers modulating the influence of leaf chemistry on breakdown. Across all data representing 85 plant genera, the Ea was 0.34 ± 0.04 eV, or approximately half the value (0.65 eV) predicted by metabolic theory. Our results indicate that average breakdown rates may increase by 5-21% with a 1-4 °C rise in water temperature, rather than a 10-45% increase expected, according to metabolic theory. Differential warming of tropical and temperate biomes could result in a similar proportional increase in breakdown rates, despite variation in Ea values for these regions (0.75 ± 0.13 eV and 0.27 ± 0.05 eV, respectively). The relative proportions of gaseous C loss and organic matter transport downstream should not change with rising temperature given that Ea values for breakdown mediated by microbes alone and microbes plus detritivores were similar at the global scale.

Metacommunity theory meets restoration: isolation may mediate how ecological communities respond to stream restoration.

An often-cited benefit of river restoration is an increase in biodiversity or shift in composition to more desirable taxa. Yet, hard manipulations of habitat structure often fail to elicit a significant response in terms of biodiversity patterns. In contrast to conventional wisdom, the dispersal of organisms may have as large an influence on biodiversity patterns as environmental conditions. This influence of dispersal may be particularly influential in river networks that are linear branching, or dendritic, and thus constrain most dispersal to the river corridor. As such, some locations in river networks, such as isolated headwaters, are expected to respond less to environmental factors and less by dispersal than more well-connected downstream reaches. We applied this metacommunity framework to study how restoration drives biodiversity patterns in river networks. By comparing assemblage structure in headwater vs. more well-connected mainstem sites, we learned that headwater restoration efforts supported higher biodiversity and exhibited more stable ecological communities compared with adjacent, unrestored reaches. Such differences were not evident in mainstem reaches. Consistent with theory and mounting empirical evidence, we attribute this finding to a relatively higher influence of dispersal-driven factors on assemblage structure in more well-connected, higher order reaches. An implication of this work is that, if biodiversity is to be a goal of restoration activity, such local manipulations of habitat should elicit a more profound response in small, isolated streams than in larger downstream reaches. These results offer another significant finding supporting the notion that restoration activity cannot proceed in isolation of larger-scale, catchment-level degradation.

Manipulation of local environment produces different diversity outcomes depending on location within a river network.

Ecologists have long been interested in mechanisms governing community composition and assembly. Spatial connectivity is one potential mechanism that can have a large influence on community processes. In accordance with network metrics such as closeness and betweenness, headwater streams are more isolated than mainstem streams. Theory and observational studies predict that community structure in isolated locations of dispersal networks should respond more strongly to manipulations of local conditions, whereas well-connected communities subject to high levels of dispersal should not respond strongly to local manipulations. We experimentally investigated this prediction by manipulating habitat complexity in headwaters and mainstem streams while monitoring macroinvertebrate communities through time. As predicted, the manipulation of local habitat had a stronger influence in headwaters than mainstreams. Both taxon richness and community similarity showed strong responses to alterations in habitat complexity in headwaters, but not in mainstem streams. These findings support the hypothesis that location within a dispersal network affects the relative importance of local and regional factors in structuring the local communities within a spatially structured metacommunity. In addition, our results suggest that conservation strategies need to account for the possibility that the relative importance of local and regional drivers of community composition and assembly can vary spatially.

ECG myocardial scar quantification predicts reverse left ventricular remodeling and survival after cardiac resynchronization therapy implantation: A retrospective pilot study.

INTRODUCTION: Electrocardiographic (ECG) LV scar quantification may improve prediction of CRT response. METHODS AND RESULTS: Data were abstracted in 76 patients who underwent a first CRT implantation at 2 US centers. Selvester QRS scar quantification was performed using the LBBB modified QRS scoring method. Seven clinical variables previously associated with reverse LV remodeling (RLVR) and QRS score were included in logistic regression analysis. Survival was compared across QRS score quartiles using Kaplan-Meier curves. RLVR occurred more frequently in patients with QRS score ≤ 5 (63%) than QRS score>5 (22%), (OR=5.83, 95% CI=2.11-16.07). After adjustment for clinical variables using logistic regression, QRS score>5 predicted RLVR (Chi-square=20.3, P=0.005, AUC=0.782). Patients in the lowest quartile of QRS score (<4) had improved survival compared to patients in the other QRS score quartiles (P=0.037). CONCLUSION: ECG quantified LV scar predicts RLVR and long-term survival in patients with LBBB undergoing CRT implantation.

Current street tree communities reflect race-based housing policy and modern attempts to remedy environmental injustice.

Humans promote and inhibit other species on the urban landscape, shaping biodiversity patterns. Institutional racism may underlie the distribution of urban species by creating disproportionate resources in space and time. Here, we examine whether present-day street tree occupancy, diversity, and composition in Baltimore, MD, USA, neighborhoods reflect their 1937 classification into grades of loan risk-from most desirable (A = green) to least desirable (D = "redlined")-using racially discriminatory criteria. We find that neighborhoods that were redlined have consistently lower street tree α-diversity and are nine times less likely to have large (old) trees occupying a viable planting site. Simultaneously, redlined neighborhoods were locations of recent tree planting activities, with a high occupancy rate of small (young) trees. However, the community composition of these young trees exhibited lower species turnover and reordering across neighborhoods compared to those in higher grades, due to heavy reliance on a single tree species. Overall, while the negative effects of redlining remain detectable in present-day street tree communities, there are clear signs of recent investment. A strategy of planting diverse tree cohorts paired with investments in site rehabilitation and maintenance may be necessary if cities wish to overcome ecological feedbacks associated with legacies of environmental injustice.

Detection and characterisation of Bordetella hinzii in line-related bacteraemia and respiratory tract infection in Australia.

Bordetella hinzii has emerged as an unusual cause of infection in immunocompromised patients, previously linked to zoonotic transmission. Antimicrobial susceptibility and genetic diversity of B. hinzii are poorly understood. This study reports phenotypic and genomic characteristics of the first four Australian isolates of B. hinzii obtained from elderly immunocompromised patients. Bordetella hinzii isolates were identified by MALDI-TOF and whole genome sequencing (WGS). Antibiotic susceptibility testing was performed using disk diffusion or E-test. Genomes of B. hinzii were analysed in global context. A phylogenetic tree was constructed of all isolates using Roary and a maximum-likelihood tree was generated from the core-snp alignment. Bordetella hinzii minimum inhibitory concentrations (MICs) were largely uniform with high MICs to ampicillin, ceftriaxone and ciprofloxacin and low MICs to meropenem and piperacillin-tazobactam. Genomic analysis of isolate sequences divided strains analysed into two phylogenetically distinct groups, with one Australian B. hinzii isolate (AUS-4) assigned to Group 1, and the remaining isolates (AUS1-AUS3 and AUS-5) to Group 2. Single nucleotide polymorphism (SNP) analysis revealed two isolates, AUS-1 and AUS-2, were closely related with 14 SNP differences between them. All other Australian isolates were unrelated to each and all other isolates from the international dataset. Bordetella hinzii appears to pose a risk to immunocompromised individuals but remains susceptible to extended spectrum ß-lactam and carbapenem antibiotics. Genomic analysis suggested a dissemination of genetically distinct strains.

Diversity-stability relationships across organism groups and ecosystem types become decoupled across spatial scales.

The relationship between biodiversity and stability, or its inverse, temporal variability, is multidimensional and complex. Temporal variability in aggregate properties, like total biomass or abundance, is typically lower in communities with higher species diversity (i.e., the diversity-stability relationship [DSR]). At broader spatial extents, regional-scale aggregate variability is also lower with higher regional diversity (in plant systems) and with lower spatial synchrony. However, focusing exclusively on aggregate properties of communities may overlook potentially destabilizing compositional shifts. It is not yet clear how diversity is related to different components of variability across spatial scales, nor whether regional DSRs emerge across a broad range of organisms and ecosystem types. To test these questions, we compiled a large collection of long-term metacommunity data spanning a wide range of taxonomic groups (e.g., birds, fish, plants, invertebrates) and ecosystem types (e.g., deserts, forests, oceans). We applied a newly developed quantitative framework for jointly analyzing aggregate and compositional variability across scales. We quantified DSRs for composition and aggregate variability in local communities and metacommunities. At the local scale, more diverse communities were less variable, but this effect was stronger for aggregate than compositional properties. We found no stabilizing effect of γ-diversity on metacommunity variability, but ß-diversity played a strong role in reducing compositional spatial synchrony, which reduced regional variability. Spatial synchrony differed among taxa, suggesting differences in stabilization by spatial processes. However, metacommunity variability was more strongly driven by local variability than by spatial synchrony. Across a broader range of taxa, our results suggest that high γ-diversity does not consistently stabilize aggregate properties at regional scales without sufficient spatial ß-diversity to reduce spatial synchrony.

The effects of local filtering processes on the structure and functioning of native plant communities in experimental urban habitats.

Despite a growing literature-base devoted to document biodiversity patterns in cities, little is known about the processes that influence these patterns, and whether they are consistent over time. In particular, numerous studies have identified the capacity of cities to host a rich diversity of plant species. This trend, however, is driven primarily by introduced species, which comprise a large proportion of the urban species pool relative to natives. Using an experimental common garden study, we assessed the relative influence of local assembly processes (i.e., soil environmental filtering and competition from spontaneous urban species) on the taxonomic and functional diversity of native plant communities sampled over four seasons in 2016-2018. Taxonomic and functional diversity exhibited different responses to local processes, supporting the general conclusion that species- and trait-based measures of biodiversity offer distinct insights into community assembly dynamics. Additionally, we found that neither soil nor competition from spontaneous urban species influenced taxonomic or functional composition of native species. Functional composition, however, did shift strongly over time and was driven by community-weighted mean differences in both measured traits (maximum height, Hmax; specific leaf area, SLA; leaf chlorophyll a fluorescence, Chl a) and the relative proportions of different functional groups (legumes, annual and biennial-perennial species, C4 grasses, and forbs). By contrast, taxonomic composition only diverged between early and late seasons. Overall, our results indicate that native species are not only capable of establishing and persisting in vacant urban habitats, they can functionally respond to local filtering pressures over time. This suggests that regional dispersal limitation may be a primary factor limiting native species in urban environments. Thus, future regreening and management plans should focus on enhancing the dispersal potential of native plant species in urban environments, in order to achieve set goals for increasing native species diversity and associated ecosystem services in cities.

Clinical Performance of Real-Time Polymerase Chain Reaction for Strongyloides stercoralis Compared with Serology in a Nonendemic Setting.

Strongyloides stercoralis is a nematode endemic to subtropical and tropical regions that may cause asymptomatic carriage, peripheral eosinophilia, cutaneous, gastrointestinal, and pulmonary disease, or hyperinfection syndrome. Conventional diagnostic methods for strongyloidiasis include feces microscopy and culture, with low sensitivity in chronic infection due to the low helminth burden, and serology, which may be prone to false-negative results with immunocompromise and false-positive results with other infections and immunological disorders. We evaluated a laboratory-developed real-time polymerase chain reaction (RT-PCR), detecting the 18S SSU ribosomal RNA gene, compared with conventional diagnostic methods, using serology via ELISA as the gold-standard. The population studied included tertiary hospital inpatients and outpatients residing in a nonendemic area. Seven hundred fifty unfixed stool specimens submitted sequentially between 2014 and 2018 were tested for S. stercoralis via microscopy and RT-PCR. Agar plate culture (APC), Harada-Mori culture (HMC), and ELISA were performed in conjunction with 141, 135, and 177 of the specimens, respectively. RT-PCR yielded 13 positive and 730 negative results, with inhibition in seven specimens. ELISA yielded 53 positive, 18 equivocal, and 106 negative results. Results for direct diagnostic methods obtained after treatment with ivermectin were excluded from the performance analysis. Compared with ELISA, RT-PCR, microscopy, APC, and HMC exhibited sensitivities of 38%, 6%, 3%, and 0%, respectively, and specificities of 100%. Given the low sensitivities commensurate with testing a population with remote infection and thus low parasite burden, we recommend a combination of serological and molecular diagnostic testing to achieve the best balance of sensitivity and specificity.

Loss of phylogenetic diversity under landscape change.

Habitat alteration and destruction are primary drivers of biodiversity loss. However, the evolutionary dimensions of biodiversity loss remain largely unexplored in many systems. For example, little is known about how habitat alteration/loss can lead to phylogenetic deconstruction of ecological assemblages at the local level. That is, while species loss is evident, are some lineages favored over others? Using a long-term dataset of a globally, ecologically important guild of invertebrate consumers, stream leaf "shredders," we created a phylogenetic tree of the taxa in the regional species pool, calculated mean phylogenetic distinctiveness for >1000 communities spanning >10 year period, and related species richness, phylogenetic diversity, and distinctiveness to watershed-scale impervious cover. Using a combination of changepoint and compositional analyses, we learned that increasing impervious cover produced marked reductions in all three measures of diversity. These results aid in understanding both phylogenetic diversity and mean assemblage phylogenetic distinctiveness. Our findings indicate that, not only are species lost when there is an increase in watershed urbanization, as other studies have demonstrated, but that those lost are members of more distinct lineages relative to the community as a whole..

Incubation time, functional litter diversity, and habitat characteristics predict litter-mixing effects on decomposition.

Plant diversity influences many fundamental ecosystem functions, including carbon and nutrient dynamics, during litter breakdown. Mixing different litter species causes litter mixtures to lose mass at different rates than expected from component species incubated in isolation. Such nonadditive litter-mixing effects on breakdown processes often occur idiosyncratically because their direction and magnitude change with incubation time, litter species composition, and ecosystem characteristics. Taking advantage of results from 18 litter mixture experiments in streams, we examined whether the direction and magnitude of nonadditive mixing effects are randomly determined. Across 171 tested litter mixtures and 510 incubation time-by-mixture combinations, nonadditive effects on breakdown were common and on average resulted in slightly faster decomposition than expected. In addition, we found that the magnitude of nonadditive effects and the relative balance of positive and negative responses in mixtures change predictably over time, and both were related to an index of functional litter diversity and selected environmental characteristics. Based on these, it should be expected that nonadditive effects are stronger for litter mixtures made of functionally dissimilar species especially in smaller streams. Our findings demonstrate that effects of litter diversity on plant mixture breakdown are more predictable than generally thought. We further argue that the consequences of current worldwide homogenization in the composition of plant traits on carbon and nutrient dynamics could be better inferred from long-duration experiments that manipulate both functional litter diversity and ecosystem characteristics in "hotspots of biodiversity effects," such as small streams.

The interaction between spatial variation in habitat heterogeneity and dispersal on biodiversity in a zooplankton metacommunity.

It is hypothesized that biodiversity is maintained by interactions at local and regional spatial scales. Many sustainability plans and management practices reflect the need to conserve biodiversity, yet once these plans are implemented, the ecological consequences are not well understood. By learning how management practices affect local environmental factors and dispersal in a region, ecologists and natural resource managers can better understand the implications of management choices. We investigated the interaction of local and regional scale processes in the built environment, where human-impacts are known to influence both. Our goal was to determine how the interaction between spatial variation in habitat heterogeneity in algal management of urban ponds and dispersal shape biodiversity at local and regional spatial scales. A twelve-week mesocosm study was conducted where pond management and dispersal were manipulated to determine how spatial variation in habitat and dispersal from various source pools influence zooplankton metacommunities in urban stormwater ponds. We hypothesized that dispersal from managed or unmanaged source pools will lead to community divergence and local management practices will act as an environmental filter, both reducing beta diversity between managed ponds and driving compositional divergence. Our results suggest that zooplankton dispersal from managed or unmanaged source pools was important to explaining divergence in community composition. Furthermore, local management of algae marginally reduced compositional turnover of zooplankton among ponds but did not lead to significant divergence in community composition. Management practices may act as strong environmental filters by reducing beta diversity between ponds. As hypothesized, source pool constraints led to compositional divergence and local management practices resulted in reduced compositional turnover between ponds. The results of this study suggest that sustainability and management plans may have complex effects on biodiversity both within and across spatial scales.

The application of metacommunity theory to the management of riverine ecosystems.

River managers strive to use the best available science to sustain biodiversity and ecosystem function. To achieve this goal requires consideration of processes at different scales. Metacommunity theory describes how multiple species from different communities potentially interact with local-scale environmental drivers to influence population dynamics and community structure. However, this body of knowledge has only rarely been used to inform management practices for river ecosystems. In this paper, we present a conceptual model outlining how the metacommunity processes of local niche sorting and dispersal can influence the outcomes of management interventions and provide a series of specific recommendations for applying these ideas as well as research needs. In all cases, we identify situations where traditional approaches to riverine management could be enhanced by incorporating an understanding of metacommunity dynamics. A common theme is developing guidelines for assessing the metacommunity context of a site or region, evaluating how that context may affect the desired outcome, and incorporating that understanding into the planning process and methods used. To maximize the effectiveness of management activities, scientists and resource managers should update the toolbox of approaches to riverine management to reflect theoretical advances in metacommunity ecology.

Microbiology of pancreatoduodenectomy and recommendations for antimicrobial prophylaxis.

BACKGROUND: The microbiology of pancreatoduodenectomy is challenging and published guidelines regarding perioperative antimicrobial prophylaxis are variable with poor adherence. METHODS: A retrospective analysis of the microbiological results of 294 consecutive patients who underwent pancreatoduodenectomy was performed. Intraoperative specimen culture results were available for 50 patients and their medical records were reviewed to determine the following demographics and factors; age; sex; tumour location, histopathology, grade and stage; neoadjuvant chemotherapy and radiotherapy; preoperative biliary stenting; surgeon; surgery type and antimicrobial prophylaxis coverage. Outcomes assessed included; post-operative infections, mortality (all and 90-day), and intensive care unit and hospital admission durations. Univariate analysis with chi-squared testing was performed. RESULTS: Intraoperative specimen cultures were positive in 48 (96%) patients and polymicrobial in 45 (90%) patients with a predominance of Enterobacteriaceae (38/76%), Enterococcus species (27/54%), and Candida species (25/50%). Isolates were potentially susceptible to the current perioperative antimicrobial prophylaxis regimen of ceftriaxone with or without metronidazole in only six patients. However, only neoadjuvant radiotherapy was associated with statistically significant increased intensive care unit and hospital admission durations. CONCLUSION: Although this study was probably underpowered to detect any statistically significant associations, perioperative antimicrobial prophylaxis coverage of the operative field microbiological milieu of pancreatoduodenectomy is logical and current guidelines may be inadequate.