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30 result(s) for "Sayers, Christopher J"
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Elevated mercury exposure in bird communities inhabiting Artisanal and Small-Scale Gold Mining landscapes of the southeastern Peruvian Amazon
Artisanal and Small-Scale Gold Mining (ASGM) represents a significant source of anthropogenic mercury emissions to the environment, with potentially severe implications for avian biodiversity. In the Madre de Dios department of the southern Peruvian Amazon, ASGM activities have created landscapes marred by deforestation and post-mining water bodies (mining ponds) with notable methylation potential. While data on Hg contamination in terrestrial wildlife remains limited, this study measures Hg exposure in several terrestrial bird species as bioindicators. Total Hg (THg) levels in feathers from birds near water bodies, including mining ponds associated with ASGM areas and oxbow lakes, were analyzed. Our results showed significantly higher Hg concentrations in birds from ASGM sites with mean ± SD of 3.14 ± 7.97 µg/g (range: 0.27 to 72.75 µg/g, n  = 312) compared to control sites with a mean of 0.47 ± 0.42 µg/g (range: 0.04 to 1.89 µg/g, n  = 52). Factors such as trophic guilds, ASGM presence, and water body area significantly influenced feather Hg concentrations. Notably, piscivorous birds exhibited the highest Hg concentration (31.03 ± 25.25 µg/g, n = 12) exceeding known concentrations that affect reproductive success, where one measurement of Chloroceryle americana (Green kingfisher; 72.7 µg/g) is among the highest ever reported in South America. This research quantifies Hg exposure in avian communities in Amazonian regions affected by ASGM, highlighting potential risks to regional bird populations.
Mercury in Neotropical birds: a synthesis and prospectus on 13 years of exposure data
Environmental mercury (Hg) contamination of the global tropics outpaces our understanding of its consequences for biodiversity. Knowledge gaps of pollution exposure could obscure conservation threats in the Neotropics: a region that supports over half of the world’s species, but faces ongoing land-use change and Hg emission via artisanal and small-scale gold mining (ASGM). Due to their global distribution and sensitivity to pollution, birds provide a valuable opportunity as bioindicators to assess how accelerating Hg emissions impact an ecosystem’s ability to support biodiversity, and ultimately, global health. We present the largest database on Neotropical bird Hg concentrations (n = 2316) and establish exposure baselines for 322 bird species spanning nine countries across Central America, South America, and the West Indies. Patterns of avian Hg exposure in the Neotropics broadly align with those in temperate regions: consistent bioaccumulation across functional groups and high spatiotemporal variation. Bird species occupying higher trophic positions and aquatic habitats exhibited elevated Hg concentrations that have been previously associated with reductions in reproductive success. Notably, bird Hg concentrations were over four times higher at sites impacted by ASGM activities and differed by season for certain trophic niches. We developed this synthesis via a collaborative research network, the Tropical Research for Avian Conservation and Ecotoxicology (TRACE) Initiative, which exemplifies inclusive, equitable, and international data-sharing. While our findings signal an urgent need to assess sampling biases, mechanisms, and consequences of Hg exposure to tropical avian communities, the TRACE Initiative provides a meaningful framework to achieve such goals. Ultimately, our collective efforts support and inform local, scientific, and government entities, including Parties of the United Nations Minamata Convention on Mercury, as we continue working together to understand how Hg pollution impacts biodiversity conservation, ecosystem function, and public health in the tropics.HighlightsWe summarized the largest database on Neotropical bird Hg concentrations to identify major patterns of pollution exposure to terrestrial biodiversity in the tropics.We detected the highest Hg concentrations in carnivorous bird species, aquatic habitats, and gold mining sites.We showcase among the highest published Hg concentrations for songbirds (Passeriformes) in the world.Madre de Dios, Peru, central Belize, and Ayapel, Colombia are biological Hg hotspots, but widespread sampling is necessary throughout the Neotropics.Inclusive collaboration will excel the field of tropical ecotoxicology by improving the efficiency and comparability of future monitoring efforts.
Geographic variation of mercury in breeding tidal marsh sparrows of the northeastern United States
Saltmarsh sparrows (Ammospiza caudacuta) and seaside sparrows (A. maritima) are species of conservation concern primarily due to global sea-level rise and habitat degradation. Environmental mercury (Hg) contamination may present additional threats to their reproductive success and survival. To assess site-specific total mercury (THg) exposure and identify environmental correlates of THg detection, we sampled blood from adult male saltmarsh and seaside sparrows at 27 sites between Maine and Virginia, USA. The mean THg concentration (±1 SD) throughout the entire sampling range was 0.531 ± 0.287 µg/g wet weight (ww) for saltmarsh sparrows and 0.442 ± 0.316 µg/g ww for seaside sparrows. Individual THg concentrations ranged from 0.135–1.420 µg/g ww for saltmarsh sparrows and 0.153–1.530 µg/g ww for seaside sparrows. Model averaging from a suite of linear mixed models showed that saltmarsh sparrows averaged 20.1% higher blood THg concentrations than seaside sparrows, potentially due to differences in diet or foraging behavior. We found no evidence for a relationship between sparrow THg concentrations and land cover surrounding sampled marshes or average precipitation-based Hg deposition. Overall, our results suggest considerable, unexplained variation in tidal marsh sparrow blood THg concentrations over their co-occurring breeding ranges.
Simultaneous passive acoustic monitoring uncovers evidence of potentially overlooked temporal variation in an Amazonian bird community
The vocal activity and detectability of tropical birds are subject to high levels of temporal heterogeneity, but quantifying patterns of diel and day-to-day variation in complex systems is challenging with traditional point count methods. As a result, research concerning stochastic temporal effects on tropical avian assemblages is limited, typically offering only broad conclusions, e.g., overall activity is highest in the first few hours of the morning and some species are active at different times of the day. Passive acoustic monitoring introduces several advantages for studying temporal variation, particularly by enabling simultaneous and continuous data collection across adjacent sites. Here, we employed autonomous recording units to quantify temporal variation in avian vocal activity and observed species richness at an Amazonian reserve in Madre de Dios, Peru—a region featuring some of Earth’s richest, most complex avian assemblages. We manually annotated 18 dawn hour recordings, collected simultaneously from three separate days at the same six sites, which represent various microhabitats and avian community compositions. We documented significant and consistent temporal variation in avian vocal activity levels and observed species richness within the dawn hour and across days. We found that temporal effects were stronger for vocal activity than for observed species richness and that vocal activity patterns over the course of the dawn hour varied on a species-to-species basis. Our results indicate that overlooked temporal variation in Amazonian soundscapes may obfuscate the results of surveys that fail to sufficiently account for temporal variables with simultaneous monitoring. While manual analysis of large volumes of soundscape data remains challenging, such data should be collected as a supplement to traditional surveys whenever possible. Rapidly advancing research concerning the automated processing of acoustic data could lead to more efficient methods for reducing temporal bias and improving the calibration and accuracy of ornithological surveys in the tropics.
Opportunities for moderate-range electric vehicles using sustainable sodium-ion batteries
Today’s sodium-ion batteries can not only be used in stationary energy storage applications, but also in 160–280 mile driving-range five-passenger electric vehicles. This technology will alleviate some of the supply-chain issues arising from limited resources of materials used in the ubiquitous lithium-ion batteries.
The Initial Relationship Between the United States Department of Health and Human Services’ Digital COVID-19 Public Education Campaign and Vaccine Uptake: Campaign Effectiveness Evaluation
Over 1 million people in the United States have died of COVID-19. In response to this public health crisis, the US Department of Health and Human Services launched the We Can Do This public education campaign in April 2021 to increase vaccine confidence. The campaign uses a mix of digital, television, print, radio, and out-of-home channels to reach target audiences. However, the impact of this campaign on vaccine uptake has not yet been assessed. We aimed to address this gap by assessing the association between the We Can Do This COVID-19 public education campaign's digital impressions and the likelihood of first-dose COVID-19 vaccination among US adults. A nationally representative sample of 3642 adults recruited from a US probability panel was surveyed over 3 waves (wave 1: January to February 2021; wave 2: May to June 2021; and wave 3: September to November 2021) regarding COVID-19 vaccination, vaccine confidence, and sociodemographics. Survey data were merged with weekly paid digital campaign impressions delivered to each respondent's media market (designated market area [DMA]) during that period. The unit of analysis was the survey respondent-broadcast week, with respondents nested by DMA. Data were analyzed using a multilevel logit model with varying intercepts by DMA and time-fixed effects. The We Can Do This digital campaign was successful in encouraging first-dose COVID-19 vaccination. The findings were robust to multiple modeling specifications, with the independent effect of the change in the campaign's digital dose remaining practically unchanged across all models. Increases in DMA-level paid digital campaign impressions in a given week from -30,000 to 30,000 increased the likelihood of first-dose COVID-19 vaccination by 125%. Results from this study provide initial evidence of the We Can Do This campaign's digital impact on vaccine uptake. The size and length of the Department of Health and Human Services We Can Do This public education campaign make it uniquely situated to examine the impact of a digital campaign on COVID-19 vaccination, which may help inform future vaccine communication efforts and broader public education efforts. These findings suggest that campaign digital dose is positively associated with COVID-19 vaccination uptake among US adults; future research assessing campaign impact on reduced COVID-19-attributed morbidity and mortality and other benefits is recommended. This study indicates that digital channels have played an important role in the COVID-19 pandemic response. Digital outreach may be integral in addressing future pandemics and could even play a role in addressing nonpandemic public health crises.
Timing of radiotherapy after radical prostatectomy (RADICALS-RT): a randomised, controlled phase 3 trial
The optimal timing of radiotherapy after radical prostatectomy for prostate cancer is uncertain. We aimed to compare the efficacy and safety of adjuvant radiotherapy versus an observation policy with salvage radiotherapy for prostate-specific antigen (PSA) biochemical progression. We did a randomised controlled trial enrolling patients with at least one risk factor (pathological T-stage 3 or 4, Gleason score of 7–10, positive margins, or preoperative PSA ≥10 ng/mL) for biochemical progression after radical prostatectomy (RADICALS-RT). The study took place in trial-accredited centres in Canada, Denmark, Ireland, and the UK. Patients were randomly assigned in a 1:1 ratio to adjuvant radiotherapy or an observation policy with salvage radiotherapy for PSA biochemical progression (PSA ≥0·1 ng/mL or three consecutive rises). Masking was not deemed feasible. Stratification factors were Gleason score, margin status, planned radiotherapy schedule (52·5 Gy in 20 fractions or 66 Gy in 33 fractions), and centre. The primary outcome measure was freedom from distant metastases, designed with 80% power to detect an improvement from 90% with salvage radiotherapy (control) to 95% at 10 years with adjuvant radiotherapy. We report on biochemical progression-free survival, freedom from non-protocol hormone therapy, safety, and patient-reported outcomes. Standard survival analysis methods were used. A hazard ratio (HR) of less than 1 favoured adjuvant radiotherapy. This study is registered with ClinicalTrials.gov, NCT00541047. Between Nov 22, 2007, and Dec 30, 2016, 1396 patients were randomly assigned, 699 (50%) to salvage radiotherapy and 697 (50%) to adjuvant radiotherapy. Allocated groups were balanced with a median age of 65 years (IQR 60–68). Median follow-up was 4·9 years (IQR 3·0–6·1). 649 (93%) of 697 participants in the adjuvant radiotherapy group reported radiotherapy within 6 months; 228 (33%) of 699 in the salvage radiotherapy group reported radiotherapy within 8 years after randomisation. With 169 events, 5-year biochemical progression-free survival was 85% for those in the adjuvant radiotherapy group and 88% for those in the salvage radiotherapy group (HR 1·10, 95% CI 0·81–1·49; p=0·56). Freedom from non-protocol hormone therapy at 5 years was 93% for those in the adjuvant radiotherapy group versus 92% for those in the salvage radiotherapy group (HR 0·88, 95% CI 0·58–1·33; p=0·53). Self-reported urinary incontinence was worse at 1 year for those in the adjuvant radiotherapy group (mean score 4·8 vs 4·0; p=0·0023). Grade 3–4 urethral stricture within 2 years was reported in 6% of individuals in the adjuvant radiotherapy group versus 4% in the salvage radiotherapy group (p=0·020). These initial results do not support routine administration of adjuvant radiotherapy after radical prostatectomy. Adjuvant radiotherapy increases the risk of urinary morbidity. An observation policy with salvage radiotherapy for PSA biochemical progression should be the current standard after radical prostatectomy. Cancer Research UK, MRC Clinical Trials Unit, and Canadian Cancer Society.
Responses to acute infection with SARS-CoV-2 in the lungs of rhesus macaques, baboons and marmosets
Non-human primate models will expedite therapeutics and vaccines for coronavirus disease 2019 (COVID-19) to clinical trials. Here, we compare acute severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in young and old rhesus macaques, baboons and old marmosets. Macaques had clinical signs of viral infection, mild to moderate pneumonitis and extra-pulmonary pathologies, and both age groups recovered in two weeks. Baboons had prolonged viral RNA shedding and substantially more lung inflammation compared with macaques. Inflammation in bronchoalveolar lavage was increased in old versus young baboons. Using techniques including computed tomography imaging, immunophenotyping, and alveolar/peripheral cytokine response and immunohistochemical analyses, we delineated cellular immune responses to SARS-CoV-2 infection in macaque and baboon lungs, including innate and adaptive immune cells and a prominent type-I interferon response. Macaques developed T-cell memory phenotypes/responses and bystander cytokine production. Old macaques had lower titres of SARS-CoV-2-specific IgG antibody levels compared with young macaques. Acute respiratory distress in macaques and baboons recapitulates the progression of COVID-19 in humans, making them suitable as models to test vaccines and therapies. Acute respiratory distress in macaques and baboons recapitulates COVID-19 disease progression in humans, making them suitable as models to test vaccines and therapies.
Genome-wide association analysis identifies six new loci associated with forced vital capacity
Stephanie London, Martin Tobin and colleagues report meta-analyses of genome-wide association studies for forced vital capacity (FVC), a spirometric measure of pulmonary function that reflects lung volume. They identify six regions newly associated with FVC and demonstrate that candidate genes at these loci are expressed in lung tissue and primary lung cells. Forced vital capacity (FVC), a spirometric measure of pulmonary function, reflects lung volume and is used to diagnose and monitor lung diseases. We performed genome-wide association study meta-analysis of FVC in 52,253 individuals from 26 studies and followed up the top associations in 32,917 additional individuals of European ancestry. We found six new regions associated at genome-wide significance ( P < 5 × 10 −8 ) with FVC in or near EFEMP1 , BMP6 , MIR129-2 – HSD17B12 , PRDM11 , WWOX and KCNJ2 . Two loci previously associated with spirometric measures ( GSTCD and PTCH1 ) were related to FVC. Newly implicated regions were followed up in samples from African-American, Korean, Chinese and Hispanic individuals. We detected transcripts for all six newly implicated genes in human lung tissue. The new loci may inform mechanisms involved in lung development and the pathogenesis of restrictive lung disease.
Spatial patterns of immunogenetic and neutral variation underscore the conservation value of small, isolated American badger populations
Small and isolated populations often exhibit low genetic diversity due to drift and inbreeding, but may simultaneously harbour adaptive variation. We investigate spatial distributions of immunogenetic variation in American badger subspecies (Taxidea taxus), as a proxy for evaluating their evolutionary potential across the northern extent of the species’ range. We compared genetic structure of 20 microsatellites and the major histocompatibility complex (MHC DRB exon 2) to evaluate whether small, isolated populations show low adaptive polymorphism relative to large and well‐connected populations. Our results suggest that gene flow plays a prominent role in shaping MHC polymorphism across large spatial scales, while the interplay between gene flow and selection was stronger towards the northern peripheries. The similarity of MHC alleles within subspecies relative to their neutral genetic differentiation suggests that adaptive divergence among subspecies can be maintained despite ongoing gene flow along subspecies boundaries. Neutral genetic diversity was low in small relative to large populations, but MHC diversity within individuals was high in small populations. Despite reduced neutral genetic variation, small and isolated populations harbour functional variation that likely contribute to the species evolutionary potential at the northern range. Our findings suggest that conservation approaches should focus on managing adaptive variation across the species range rather than protecting subspecies per se.