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18 result(s) for "Johnston, Elliot M."
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To feed the world, recognize the interconnectedness of aquaculture and fisheries
Efforts to scale up aquaculture are increasingly framed as essential to global food security and ocean sustainability, yet such narratives often obscure the complex and interdependent relationships between aquaculture and wild-capture fisheries. This paper critically interrogates the dominant “feed the world” framing of aquaculture expansion, arguing that treating aquaculture and fisheries as isolated systems undermines social equity, ecological sustainability, and effective food policy. Drawing on a novel classification of twenty-one aquaculture–wild fishery interaction types spanning ecological, economic, and social dimensions, we highlight the inadequacy of current policy frameworks that ignore these entanglements. Through mixed methods, including global time-series data and in-depth case studies from countries such as Chile, Fiji, Vietnam, and Zambia, the analysis reveals that aquaculture expansion often displaces traditional fisheries, privatizes marine space, exacerbates gender and class inequalities, and privileges export-oriented production over local food systems. The study argues for a paradigm shift in seafood governance that reframes aquaculture not as a stand-alone solution but as a component of deeply embedded, context-specific, and socially contested food systems. This critical lens pushes for policies that prioritize justice, local agency, and the co-governance of marine resources, challenging technocratic visions of blue growth with a call for integrated, equity-centered approaches.
Females know best: dispersal polymorphism maintained by sex-specific foraging
Polymorphisms are maintained over time by trade-offs that alternatively favor morphs over space or time. In a polyphenic population of amphibians (Arizona tiger salamander; Ambystoma mavortium nebulosum ), two morphs—paedomorphs and metamorphs—exhibit a trade-off in dispersal capacity. Larvae select between two discrete ontogenetic pathways based on environmental cues—adult paedomorphs remain in their permanent, natal pond, while adult metamorphs disperse between ponds of varying hydroperiods and overwinter in the terrestrial environment. This polyphenism is maintained in part by sex-specific reproductive advantages within each morph, with paedomorphic males achieving more reproductive opportunities and metamorphic females achieving higher egg production. In this study, we examined the role of a high-quality, primary prey taxon (fairy shrimp)—which is accessible to metamorphs only—in balancing the sex-specific component of this dispersal trade-off. Among the 95 metamorphs for which we evaluated diet and body condition, we found that most of the high-condition individuals were females that contained predominantly fairy shrimp in their stomachs. In addition, females specialized on fairy shrimp at much lower fairy shrimp densities than males, indicating that the consumption of this prey taxon may have differential fitness benefits across metamorph sexes. Our findings align with the expectations of parental investment theory, in which female reproductive success is most limited by the energetic resources necessary for egg production, while male reproductive success is limited predominantly by access to females. Significance statement Polymorphisms are a common source of phenotypic diversity in animal populations that are often maintained over time by trade-offs among morphs. In a subalpine amphibian population that exhibits a dispersal polyphenism, the dispersing morph (metamorph) can leave natal ponds and access a high-quality, ephemeral food resource (fairy shrimp) in ponds of nonpermanent hydroperiods. In this study, we quantify the spatiotemporal availability of this focal prey taxon and examine whether sex-specific foraging behavior among metamorphs could contribute to the persistence of this polyphenism. Our results suggest that fairy shrimp consumption allows metamorphs to realize benefits of the dispersal trade-off through high female fecundity. These findings emphasize the importance of considering intrapopulation variation in functional responses and how the behavior can contribute to the maintenance of polymorphisms.
Testing avian umbrella species to inform the conservation of intertidal areas in Acadia National Park, Maine
Avian species are in rapid decline worldwide, with 1 in 8 species facing extinction, and in North America shorebird species are declining at a higher proportion than other groups. The nearshore ecosystem in Maine (USA) supports several bird species that rely on intertidal and subtidal zones, including high densities of migratory shorebirds and wintering waterfowl. Additionally, Acadia National Park (ANP) includes some of the country's highest densities of declining populations of Purple Sandpipers (Calidris maritima) and state threatened Harlequin Ducks (Histrionicus histrionicus). We investigated whether the distribution of candidate umbrella species overlapped with the distribution of 5 waterfowl taxa (Common Eiders [Somateria mollissima], Long-tailed Ducks [Clangula hyemalis], Black Scoters [Melanitta americana], Bucephala spp., and Mallards [Anas platyrhynchos]), thereby examining whether conservation actions (e.g., conservation closures) taken to preserve these 2 species of high conservation concern might also benefit the larger taxonomic groups to which they belong, a concept known as umbrella species conservation. To answer this question, bird abundance surveys were conducted within ANP during 2021 and 2022, and detection and occupancy were compared among the focal groups using a hypothesis-driven model. The occupancy distributions of our 5 waterfowl taxa revealed that sites with the highest occupancy estimates for Common Eiders, Long-tailed Ducks, and Black Scoters included sites occupied by Purple Sandpipers and Harlequin Ducks. Bucephala spp. and Mallard occupancy, however, only weakly overlapped with our candidate umbrella detections, occurring in sites with the lowest and mid-range occupancy estimates. Thus, any positive effect of conservation closures based on these 2 species of concern might impact some, but not all, species we surveyed. Including more survey locations occupied by Purple Sandpipers and Harlequin Ducks would be necessary to see if this pattern is generalizable across the region. Our low sample size for umbrella species detections, however, also highlights the limited utility of using rare species as umbrellas. Las especies de aves están en un declive rápido en todo el mundo, con 1 de cada 8 especies en riesgo de extinción y en Norteamérica las especies de aves costeras están declinando a una mayor proporción que otros grupos. El ecosistema litoral en Maine (EEUU) sostiene a varias especies de aves que dependen de zonas intermareal y submareales, incluyendo altas densidades de aves playeras migratorias y aves acuáticas invernales. Adicionalmente, Acadia National Park (ANP) incluye unas de las densidades más altas del país de las poblaciones en declive de correlimo Calidris maritima y de pato Histrionicus histrionicus, amenazados a nivel estatal. Estudiamos si la distribución de especies sombrilla candidatas sobrelapaba con la distribución de 5 taxa de aves acuáticas (eider Somateria mollissima, pato Clangula hyemalis, pato negro Melanitta americana, Bucephala spp. y pato Anas platyrhynchos), por tanto examinando si las acciones de conservación (como cierres de conservación) tomadas para preservar esas 2 especies en peligro crítico también podrían beneficiar a los grupos taxonómicos más amplios a los que pertenecen, un concepto conocido como conservación de especies sombrilla. Para responder a esta pregunta, se realizaron reconocimientos de abundancia de aves en ANP durante el 2021 y el 2022, y se comparó la detección y la ocupación entre grupos focales usando un modelo guiado por hipótesis. La distribución de ocupación de nuestras 5 taxa de aves acuáticas mostraron que los sitios con los mayores estimados de ocupación para eider S. mollissima, pato C. hyemalis y pato negro Melanitta americana incluían sitios ocupados por correlimo C. maritima y pato H. histrionicus. Sin embargo, la ocupación de Bucephala spp. y de pato A. platyrhynchos sólo tuvo un débil sobrelapamiento con la detección de nuestras candidatas a especies sombrilla, en sitios con estimados de ocupación de rango medio y bajo. Entonces, cualquier conclusión positiva del efecto de conservación basada en estas 2 especies de interés puede tener algún impacto sobre algunas, pero no todas, las especies del reconocimiento. Sería necesario incluir más localidades de reconocimiento ocupadas por correlimo Calidris maritima y pato H. histrionicus para ver si este patrón es generalizable en toda la región. Nuestro bajo número de reconocimientos para la detección de especies sombrilla, sin embargo, también recalca el uso limitado de usar especies raras como especies sombrilla. Palabras clave: correlimoCalidris maritima, cosecha de algas, ecosistemas costeros, ocupación de una sola especie, pato Histrionicus histrionicus.
Testing avian umbrella species to inform the conservation of intertidal areas in Acadia National Park, Maine/Probando especies sombrilla de aves para informar conservacion de areas intermareales en Acadia National Park, Maine
Avian species are in rapid decline worldwide, with 1 in 8 species facing extinction, and in North America shorebird species are declining at a higher proportion than other groups. The nearshore ecosystem in Maine (USA) supports several bird species that rely on intertidal and subtidal zones, including high densities of migratory shorebirds and wintering waterfowl. Additionally, Acadia National Park (ANP) includes some of the country's highest densities of declining populations of Purple Sandpipers (Calidris maritima) and state threatened Harlequin Ducks (Histrionicus histrionicus). We investigated whether the distribution of candidate umbrella species overlapped with the distribution of 5 waterfowl taxa (Common Eiders [Somateria mollissima], Long-tailed Ducks [Clangula hyemalis], Black Scoters [Melanitta americana], Bucephala spp., and Mallards [Anas platyrhynchos]), thereby examining whether conservation actions (e.g., conservation closures) taken to preserve these 2 species of high conservation concern might also benefit the larger taxonomic groups to which they belong, a concept known as umbrella species conservation. To answer this question, bird abundance surveys were conducted within ANP during 2021 and 2022, and detection and occupancy were compared among the focal groups using a hypothesis-driven model. The occupancy distributions of our 5 waterfowl taxa revealed that sites with the highest occupancy estimates for Common Eiders, Long-tailed Ducks, and Black Scoters included sites occupied by Purple Sandpipers and Harlequin Ducks. Bucephala spp. and Mallard occupancy, however, only weakly overlapped with our candidate umbrella detections, occurring in sites with the lowest and mid-range occupancy estimates. Thus, any positive effect of conservation closures based on these 2 species of concern might impact some, but not all, species we surveyed. Including more survey locations occupied by Purple Sandpipers and Harlequin Ducks would be necessary to see if this pattern is generalizable across the region. Our low sample size for umbrella species detections, however, also highlights the limited utility of using rare species as umbrellas. Received 12 August 2023. Accepted 2 March 2024.
Macroalgae composition alters occupancy of multiple bird guilds in rocky intertidal communities
In the north Atlantic, rocky intertidal shores with diverse macroalgal assemblages are common. Despite this, the effect of macroalgae on bird use of these habitats is not well understood. We used a single-season, single-species occupancy framework to investigate the influence of the macroalgal assemblage on 3 bird guilds and 2 single-species groups: shorebirds (waders), scavengers, divers, common eider Somateria mollissima non-parenting adults, and common eider broods. In particular, we considered whether bird occupancy is more strongly determined by the taxonomic composition of the macroalgal assemblage or by structural characteristics of the collective assemblage. We conducted avian point counts and intertidal habitat surveys at 75 sites along the Maine (USA) coast in 2016 and 2017. Macroalgae increased the probability of site occupancy for 1 guild and 2 single-species groups. Most notably, we found that shorebird occupancy had a positive relationship with the spatial extent and mat depth of Ascophyllum nodosum, indicating a preference for more homogeneous and deeper macroalgal assemblages dominated by this common, tall-canopied taxon. In contrast, common eider presence had a positive relationship with the spatial extent of 2 categories of shorter-canopied macroalgae that are less dominant members of the macroalgal assemblage. Both shorebirds and eiders were less likely to occur in areas with steeper intertidal slopes, which provide less potential habitat during low tides. Overall, our results suggest that macroalgae composition and availability influences bird occupancy in rocky intertidal habitats, but more mechanistic studies (e.g. behavioral) are needed to understand the exact role macroalgae play in coastal bird ecology.
Oral factor xia inhibitor milvexian after a recent acute coronary syndrome: Rationale and design of the phase 3 (Librexia ACS)
Despite current antiplatelet therapy, patients remain at risk of recurrent ischemic events after acute coronary syndromes (ACS), which may reflect persistently elevated thrombin generation. Factor XIa inhibition reduces thrombin generation and may improve clinical outcomes with minimal bleeding risk. Librexia ACS (ClinicalTrials.gov NCT05754957) is a Phase 3, randomized, double-blind, placebo-controlled, event-driven trial to test the efficacy and safety of milvexian, an oral, selective factor XIa inhibitor, in addition to conventional antiplatelet therapy after a recent ACS. Eligibility criteria include symptoms of spontaneous ischemia, a diagnosis of ACS and cardiac biomarker elevation indicative of myonecrosis within 7 days before randomization, along with at least 2 risk-enhancing factors. Participants are randomly assigned to oral milvexian (25 mg twice daily) or a matched placebo. Randomization is stratified according to the planned duration and type of antiplatelet therapy. The primary efficacy endpoint is the time to first occurrence of the composite of cardiovascular death, myocardial infarction (MI), or ischemic stroke that will enroll approximately 16,000 patients with follow-up until 875 events are accrued. The first major secondary endpoint is time to the first occurrence of cardiovascular death, MI, ischemic stroke, major adverse limb events, and symptomatic venous thromboembolism. The principal safety endpoint is Bleeding Academic Research Consortium 3c or 5 bleeding. The Librexia-ACS trial will determine the efficacy and safety of milvexian after ACS and will be the first trial to test whether factor XIa inhibition in addition to standard-of-care antiplatelet therapy reduces major adverse cardiovascular events without an increased risk of significant bleeding.
Cross-sectional imaging of gastric cancer: pearls, pitfalls and lessons learned from multidisciplinary conference
Gastric cancer is rising in prevalence associated with high mortality, primarily due to late-stage detection, underscoring the imperative for early and precise diagnosis. Etiology involves an interplay of genetic susceptibilities and environmental factors with a prominent role of Helicobacter pylori infection. Due to its often-delayed symptom presentation, prompt and accurate diagnosis is necessary. A multimodal imaging approach, including endoscopic ultrasound (EUS), multi-detector computed tomography (MDCT), and magnetic resonance imaging (MRI) is critical for accurate staging. Each modality contributes unique advantages and limitations, highlighting the importance of integrating diagnostic strategy. Moreover, multidisciplinary conferences offer a vital collaborative platform, bringing together specialists from diverse fields for treatment planning. This synergistic approach not only enhances diagnostic precision but also improves patient outcome. This review highlights the critical role of imaging in diagnosis, staging, and management and advocates for interdisciplinary collaboration in early detection and comprehensive management of gastric cancer, aiming to reduce mortality.
Health-related quality of life among cervical cancer survivors at a tertiary hospital in Ghana
Cervical cancer is the second most common female cancer in Ghana. The disease and its treatment significantly affect survivors' health-related quality of life (HRQoL). We determined the overall quality of life (QoL) and identified its predictors among cervical cancer survivors after treatment. A hospital-based cross-sectional analytical study was conducted on 153 disease-free cervical cancer survivors who completed curative treatment between January 2004 and December 2018 at Komfo Anokye Teaching Hospital (KATH) in Kumasi, Ghana. We used the European Organization for Research and Treatment of Cancer core-30 item (EORTC QLQ-C30) and cervical cancer module (EORTC QLQ-CX24) to assess the survivors' overall QoL. QoL domain scores were dichotomised as affected or unaffected by disease and its treatment. Significant differences between the affected and unaffected groups within each QoL domain were determined using the student T-test. We used Kruskal-Wallis and Dunn's tests to examine the difference in QoL domains between treatment types, with significance based on Bonferroni corrections. Multivariable logistic regression was performed to identify predictors of overall QoL. A p-value of less than 0.05 was considered statistically significant. One hundred and fifty-three (153) women having a mean age of 58.3 (SD 11.4) years were studied. The overall QoL score was 79.6 (SD 16.0), and 74.5% of survivors reported good QoL score within the median follow up time of 41.8 months (interquartile range [IQR], 25.5-71.1 months) after cervical cancer diagnosis. Although the majority (66.0-84.3%) of the QoL functioning scale were unaffected, about a fifth (22.2%) to a third (34.5%) of the subjects had perceptual impairment in cognitive and role functioning. Financial difficulties, peripheral neuropathy and pain were most common symptoms reported as affected. A third of the survivors were worried that sex would be painful, and 36.6% indicated that their sexual activity as affected. The overall QoL scores for survivors who had surgery, chemoradiation and radiation-alone were 86.1 (SD 9.7), 76.9 (SD 17.7), and 80.7 (SD 14.7), respectively (p = 0.025). The predictors of survivor's overall QoL were loss of appetite [Adjusted Odd Ratio (AOR) = 9.34, 95% Confidence Interval (CI) = 2.13-35.8, p = 0.001], pain (AOR = 3.53, 95% CI = 1.25-9.31, p = 0.017) and body image (AOR = 5.89, 95% CI = 1.80-19.27, p = 0.003). About 75% of the survivors had a good overall quality of life. Primary surgical treatment affords the best prospects for quality of life with the least symptom complaints and financial burden. Loss of appetite, pain or diminution in body image perception predicted the overall quality of life of cervical cancer survivors after treatment.
Syntrophic bacterial and host–microbe interactions in bacterial vaginosis
Bacterial vaginosis (BV) is a common, polymicrobial condition of the vaginal microbiota that is associated with symptoms such as malodor and excessive discharge, along with increased risk of various adverse sequelae. Host–bacteria and bacteria–bacteria interactions are thought to contribute to the condition, but many of these functions have yet to be elucidated. Using untargeted metaproteomics, we identified 1068 host and 1418 bacterial proteins in a set of cervicovaginal lavage samples collected from 20 participants with BV and 9 who were negative for the condition. We identified Dialister micraerophilus as a major producer of malodorous polyamines and identified a syntrophic interaction between this organism and Fannyhessea vaginae that leads to increased production of putrescine, a metabolite characteristic of BV. Although formate synthesis has not previously been noted in BV, we discovered diverse bacteria associated with the condition express pyruvate formate-lyase enzymes in vivo and confirm these organisms secrete formic acid in vitro. Sodium hypophosphite efficiently inhibited this function in multiple taxa. We also found that the fastidious organism Coriobacteriales bacterium DNF00809 can metabolize formic acid secreted by Gardnerella vaginalis, representing another syntrophic interaction. We noted an increased abundance of the host epithelial repair protein transglutaminase 3 in the metaproteomic data, which we confirmed by enzyme-linked immunosorbent assay. Other proteins identified in our samples implicate Finegoldia magna and Parvimonas micra in the production of malodorous trimethylamine. Some bacterial proteins identified represent novel targets for future therapeutics to disrupt BV communities and promote vaginal colonization by commensal lactobacilli.
A syntenic pangenome of Gardnerella reveals novel plasmids and phage, taxonomic boundaries, and species-level stratification of metabolic and virulence potential
Gardnerella species are key drivers of bacterial vaginosis (BV), a prevalent condition affecting nearly one in three women of reproductive age and associated with adverse reproductive outcomes. Despite decades of study, progress in defining Gardnerella diversity has been hindered by inconsistent taxonomy and poor-quality genomic resources. Here we sequenced 392 Gardnerella isolates spanning asymptomatic and BV-associated microbiota and integrated this collection with all publicly available genomes to create a curated, high-quality reference set of 312 genomes. We resolved 21 genomic lineages encompassing 11 species and 15 subspecies using phylogenomics, average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH) and assigned each a provisional taxonomic name. Long-read assemblies enabled construction of a syntenic Gardnerella pangenome, revealing lineage-specific repertoires of virulence, metabolic, and defense, including variable sialidases (NanH), vaginolysin, and amino-acid biosynthetic pathways alongside conserved genomic organization. Comparative methylome profiling uncovered restriction-modification system diversity suggesting barriers to genetic exchange. Finally, we identified native cryptic plasmids in Gardnerella, overturning the assumption that the genus lacks plasmids. Together, these results establish a complete genomic and functional framework for Gardnerella, providing a reproducible foundation for mechanistic and translational studies of BV and a model for resolving taxonomy and functional stratification in other urogenital-associated bacteria.