107 research outputs found

    Impact of Increased Green Turtle Nesting on Loggerhead Fitness

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    Marine turtles exhibit strong fidelity to their nesting beaches, making the conservation of nesting beaches important for ensuring successful sea turtle populations. Conservation of these nesting beaches involves understanding how species interact with the environment and each other, and understanding how environmental change and population growth can affect the suitability of the nesting habitat. The Archie Carr National Wildlife Refuge (ACNWR) is unusual in its high density of sea turtle nesting by two species: green (Chelonia mydas) and loggerhead (Caretta caretta) turtles. The ACNWR in Melbourne Beach, Florida was established in 1991 due to the high density of loggerhead nesting, but in the time since it was established there has been a significant increase in green turtle nesting, from fewer than 50 nests in 1982 to over 15,000 in 2017. With such a high density of these two species in one relatively small area (21 kilometers of beach), the two species may compete for space. This is especially true for green turtles, which disturb large amounts of sand during their nesting process; in 2017, we observed 338 loggerhead clutches disturbed by nesting females during nesting surveys, nearly all of which were disturbed by green turtles. Using observed spatial and temporal nesting patterns for both green turtles and loggerheads on the ACNWR, I examined the effects these species may have on each other\u27s nests now and in the future. Additionally, green turtles and loggerheads nest in different densities along the length of the ACNWR, with green turtles more concentrated in the southern portions of the Refuge. Finally, green turtle nesting begins and peaks approximately one month later on the ACNWR than loggerhead nesting. For each of these metrics, there is both considerable overlap and distinct separation between the two species. By using these metrics in a modeling approach, I estimated the probability of nest disturbance by a subsequently nesting female, ranging from 0 to 0.105, and how these probabilities are predicted to change over time with a growing green turtle population. Evaluating the carrying capacity of this beach is important in the context of habitat disturbance, including climate change and an increase in storm frequency, and informing adaptive management strategies for effective conservation

    Near-Native Sociolinguistic Competence in French: Evidence from Variable Future-Time Expression

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    This study aims to advance the understanding of sociolinguistic competence among near-native speakers and to further knowledge about the acquisition of variable structures. We conduct a quantitative analysis of variable future-time expression in informal conversations between near-native and native speakers of French. In addition to examining linguistic constraints that have been investigated in previous research, we build on prior work by introducing a new factor that enables us to consider the role that formality of the variants plays in the use of variable future-time expression. We conclude by comparing these new findings to those for the same dataset and other variable structures (namely, negation and interrogatives, Donaldson, 2016, 2017) and by advocating for more research that consists of multiple, complementary analyses of the same dataset.Les objectifs de cette étude sont (a) d’apporter de nouvelles données relatives à la compétence sociolinguistique parmi des locuteurs non natifs qui ont un niveau très avancé dans leur langue étrangère et (b) de contribuer à nos connaissances sur l’acquisition des structures variables. Nous proposons une analyse quantitative de l’expression du futur dans des conversations informelles entre un locuteur très avancé et un locuteur natif du français. Afin de comprendre ce cas de variation, nous faisons appel à des facteurs linguistiques qui ont été identifiés dans des recherches précédentes, et nous proposons un nouveau facteur qui nous permet d’étudier le rôle joué par la formalité des variantes dans l’expression du futur. Pour conclure, nous comparons les résultats de cette analyse aux recherches précédentes qui ont examiné d’autres structures variables dans le même corpus (notamment, la négation et les interrogatives, Donaldson, 2016, 2017) et nous soulignons l’intérêt et l’importance de faire de multiples analyses complémentaires d’un seul corpus

    Assimilation of Oil-Derived Elements by Oysters Due to the Deepwater Horizon Oil Spill

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    During and after the Deepwater Horizon Oil Spill (DWHOS), oysters (Crassostrea virginica) were exposed to oil and susceptible to incidental consumption of surface and subsurface oil materials. We determined the contribution of oil materials from the DWHOS to diet of oysters by comparing carbon (C) and nitrogen (N) stable isotope ratios in oyster shell to ratios in suspended particulate matter (SPM) and in fresh and weathered oil. Average δ13C and δ15N values in oyster shell (−21 ± 1‰ and 9−11‰, respectively) were consistent with consumption of naturally available SPM as opposed to values in oil (−27 ± 0.2‰, 1.6 ± 0.4‰). Stable isotope ratios in oyster adductor muscle were similar to shell for δ15N but not δ13C, suggesting either a recent shift in diet composition or differential assimilation of C between tissue types. We found no evidence of assimilation of oil-derived C and N and, therefore, no evidence of an oyster-based conduit to higher trophic levels. Trace elements in shell were inconclusive to corroborate oil exposure. These findings are not an indication that oysters were not exposed to oil; rather they imply oysters either did not consume oil-derived materials or consumed too little to be detectable compared to natural diet

    European birth cohorts for environmental health research

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    Many pregnancy and birth cohort studies investigate the health effects of early-life environmental contaminant exposure. An overview of existing studies and their data is needed to improve collaboration, harmonization, and future project planning

    Machine learning uncovers the most robust self-report predictors of relationship quality across 43 longitudinal couples studies

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    Given the powerful implications of relationship quality for health and well-being, a central mission of relationship science is explaining why some romantic relationships thrive more than others. This large-scale project used machine learning (i.e., Random Forests) to 1) quantify the extent to which relationship quality is predictable and 2) identify which constructs reliably predict relationship quality. Across 43 dyadic longitudinal datasets from 29 laboratories, the top relationship-specific predictors of relationship quality were perceived-partner commitment, appreciation, sexual satisfaction, perceived-partner satisfaction, and conflict. The top individual-difference predictors were life satisfaction, negative affect, depression, attachment avoidance, and attachment anxiety. Overall, relationship-specific variables predicted up to 45% of variance at baseline, and up to 18% of variance at the end of each study. Individual differences also performed well (21% and 12%, respectively). Actor-reported variables (i.e., own relationship-specific and individual-difference variables) predicted two to four times more variance than partner-reported variables (i.e., the partner’s ratings on those variables). Importantly, individual differences and partner reports had no predictive effects beyond actor-reported relationship-specific variables alone. These findings imply that the sum of all individual differences and partner experiences exert their influence on relationship quality via a person’s own relationship-specific experiences, and effects due to moderation by individual differences and moderation by partner-reports may be quite small. Finally, relationship-quality change (i.e., increases or decreases in relationship quality over the course of a study) was largely unpredictable from any combination of self-report variables. This collective effort should guide future models of relationships

    Risk factors for chronic ulceration in patients with varicose veins: A case control study

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    Background/ObjectiveIdentifying which patients with varicose veins are at risk of progressing to more severe forms of chronic venous disease could help in assigning clinical priorities and targeting appropriate treatments. The aim of this study was to determine, in subjects with varicose veins, the characteristics of venous disease and other factors associated with an increased risk of ulceration.MethodsOne hundred twenty subjects with varicose veins and an open or healed venous leg ulcer were compared with 120 controls with varicose veins and no history of venous ulcer on this case control study. Subjects were recruited from hospital settings and primary care. Each subject completed a questionnaire on lifestyle and medical history and underwent an examination comprising of clinical classification of venous disease (CEAP), duplex scanning, quantitative digital photoplethysmography, and measurement of dorsiflexion. Multiple logistic regression analyses and calculation of receiver operating characteristic (ROC) curves were performed to identify the combination of factors which most accurately predicted which patients with varicose veins will develop leg ulcers.ResultsAn increased risk of ulceration was associated with the severity of clinical venous disease, especially with the presence of skin changes (P < .0001). Other significant risk factors included history of deep vein thrombosis (DVT) (P = .001), higher body mass index (BMI) (P = .006), smoking (P = .009), and reflux in the deep veins (P = .0001). Ulceration was associated with reduced volume of blood displaced as reflected by photoplethysmography and a limited range of ankle movement (not wholly due to the effects of an active ulcer) (both P < .05). Multivariate analyses showed that skin changes including lipodermatosclerosis (odds ratio [OR] 8.90, 95% confidence interval [CI] 1.44-54.8), corona phlebectatica (OR 4.52, 95% CI 1.81-11.3) and eczema (OR 2.87, 95% CI 1.12-7.07), higher BMI (OR 1.08, 95% CI 1.01-1.15), and popliteal vein reflux (OR 2.82, 95% CI 1.03-7.75) remained independently associated with increased risk of ulceration while good dorsiflexion of the ankle (OR 0.88, 95% CI 0.81-0.97) and an effective calf muscle pump (OR 0.96, 95% CI 0.92-0.99) remained protective factors. ROC curve analyses indicated that a model based on clinical observation of skin changes, duplex scanning for popliteal reflux, and calf muscle pump tests would be the most accurate in determining which patients with varicose veins develop leg ulcers.ConclusionsThe results of this study confirm that, in patients with varicose veins, those with skin changes of chronic venous insufficiency and deep vein incompetence are at greatly increased risk of ulceration. However, the risks may also be increased in those who smoke, are obese, and have restricted ankle movement and reduced calf muscle pump power

    Met-Independent Hepatocyte Growth Factor-mediated regulation of cell adhesion in human prostate cancer cells

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    BACKGROUND: Prostate cancer cells communicate reciprocally with the stromal cells surrounding them, inside the prostate, and after metastasis, within the bone. Each tissue secretes factors for interpretation by the other. One stromally-derived factor, Hepatocyte Growth Factor (HGF), was found twenty years ago to regulate invasion and growth of carcinoma cells. Working with the LNCaP prostate cancer progression model, we found that these cells could respond to HGF stimulation, even in the absence of Met, the only known HGF receptor. The new HGF binding partner we find on the cell surface may help to clarify conflicts in the past literature about Met expression and HGF response in cancer cells. METHODS: We searched for Met or any HGF binding partner on the cells of the PC3 and LNCaP prostate cancer cell models, using HGF immobilized on agarose beads. By using mass spectrometry analyses and sequencing we have identified nucleolin protein as a novel HGF binding partner. Antibodies against nucleolin (or HGF) were able to ameliorate the stimulatory effects of HGF on met-negative prostate cancer cells. Western blots, RT-PCR, and immunohistochemistry were used to assess nucleolin levels during prostate cancer progression in both LNCaP and PC3 models. RESULTS: We have identified HGF as a major signaling component of prostate stromal-conditioned media (SCM) and have implicated the protein nucleolin in HGF signal reception by the LNCaP model prostate cancer cells. Antibodies that silence either HGF (in SCM) or nucleolin (on the cell surfaces) eliminate the adhesion-stimulatory effects of the SCM. Likewise, addition of purified HGF to control media mimics the action of SCM. C4-2, an LNCaP lineage-derived, androgen-independent human prostate cancer cell line, responds to HGF in a concentration-dependent manner by increasing its adhesion and reducing its migration on laminin substratum. These HGF effects are not due to shifts in the expression levels of laminin-binding integrins, nor can they be linked to expression of the known HGF receptor Met, as neither LNCaP nor clonally-derived C4-2 sub-line contain any detectable Met protein. Even in the absence of Met, small GTPases are activated, linking HGF stimulation to membrane protrusion and integrin activation. Membrane-localized nucelolin levels increase during cancer progression, as modeled by both the PC3 and LNCaP prostate cancer progression cell lines. CONCLUSION: We propose that cell surface localized nucleolin protein may function in these cells as a novel HGF receptor. Membrane localized nucleolin binds heparin-bound growth factors (including HGF) and appears upregulated during prostate cancer progression. Antibodies against nucleolin are able to ameliorate the stimulatory effects of HGF on met-negative prostate cancer cells. HGF-nucleolin interactions could be partially responsible for the complexity of HGF responses and met expression reported in the literature

    Comprehensive Rare Variant Analysis via Whole-Genome Sequencing to Determine the Molecular Pathology of Inherited Retinal Disease

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    Inherited retinal disease is a common cause of visual impairment and represents a highly heterogeneous group of conditions. Here, we present findings from a cohort of 722 individuals with inherited retinal disease, who have had whole-genome sequencing (n = 605), whole-exome sequencing (n = 72), or both (n = 45) performed, as part of the NIHR-BioResource Rare Diseases research study. We identified pathogenic variants (single-nucleotide variants, indels, or structural variants) for 404/722 (56%) individuals. Whole-genome sequencing gives unprecedented power to detect three categories of pathogenic variants in particular: structural variants, variants in GC-rich regions, which have significantly improved coverage compared to whole-exome sequencing, and variants in non-coding regulatory regions. In addition to previously reported pathogenic regulatory variants, we have identified a previously unreported pathogenic intronic variant in CHM\textit{CHM} in two males with choroideremia. We have also identified 19 genes not previously known to be associated with inherited retinal disease, which harbor biallelic predicted protein-truncating variants in unsolved cases. Whole-genome sequencing is an increasingly important comprehensive method with which to investigate the genetic causes of inherited retinal disease.This work was supported by The National Institute for Health Research England (NIHR) for the NIHR BioResource – Rare Diseases project (grant number RG65966). The Moorfields Eye Hospital cohort of patients and clinical and imaging data were ascertained and collected with the support of grants from the National Institute for Health Research Biomedical Research Centre at Moorfields Eye Hospital, National Health Service Foundation Trust, and UCL Institute of Ophthalmology, Moorfields Eye Hospital Special Trustees, Moorfields Eye Charity, the Foundation Fighting Blindness (USA), and Retinitis Pigmentosa Fighting Blindness. M.M. is a recipient of an FFB Career Development Award. E.M. is supported by UCLH/UCL NIHR Biomedical Research Centre. F.L.R. and D.G. are supported by Cambridge NIHR Biomedical Research Centre

    Phenotypic Characterization of EIF2AK4 Mutation Carriers in a Large Cohort of Patients Diagnosed Clinically With Pulmonary Arterial Hypertension.

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    BACKGROUND: Pulmonary arterial hypertension (PAH) is a rare disease with an emerging genetic basis. Heterozygous mutations in the gene encoding the bone morphogenetic protein receptor type 2 (BMPR2) are the commonest genetic cause of PAH, whereas biallelic mutations in the eukaryotic translation initiation factor 2 alpha kinase 4 gene (EIF2AK4) are described in pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis. Here, we determine the frequency of these mutations and define the genotype-phenotype characteristics in a large cohort of patients diagnosed clinically with PAH. METHODS: Whole-genome sequencing was performed on DNA from patients with idiopathic and heritable PAH and with pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis recruited to the National Institute of Health Research BioResource-Rare Diseases study. Heterozygous variants in BMPR2 and biallelic EIF2AK4 variants with a minor allele frequency of <1:10 000 in control data sets and predicted to be deleterious (by combined annotation-dependent depletion, PolyPhen-2, and sorting intolerant from tolerant predictions) were identified as potentially causal. Phenotype data from the time of diagnosis were also captured. RESULTS: Eight hundred sixty-four patients with idiopathic or heritable PAH and 16 with pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis were recruited. Mutations in BMPR2 were identified in 130 patients (14.8%). Biallelic mutations in EIF2AK4 were identified in 5 patients with a clinical diagnosis of pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis. Furthermore, 9 patients with a clinical diagnosis of PAH carried biallelic EIF2AK4 mutations. These patients had a reduced transfer coefficient for carbon monoxide (Kco; 33% [interquartile range, 30%-35%] predicted) and younger age at diagnosis (29 years; interquartile range, 23-38 years) and more interlobular septal thickening and mediastinal lymphadenopathy on computed tomography of the chest compared with patients with PAH without EIF2AK4 mutations. However, radiological assessment alone could not accurately identify biallelic EIF2AK4 mutation carriers. Patients with PAH with biallelic EIF2AK4 mutations had a shorter survival. CONCLUSIONS: Biallelic EIF2AK4 mutations are found in patients classified clinically as having idiopathic and heritable PAH. These patients cannot be identified reliably by computed tomography, but a low Kco and a young age at diagnosis suggests the underlying molecular diagnosis. Genetic testing can identify these misclassified patients, allowing appropriate management and early referral for lung transplantation
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