8,283 research outputs found

    An improved genetic sex test for Atlantic salmon (Salmo salar L.)

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    This is the final version. Available from the publisher via the DOI in this record.Accurate determination of sex ratios is an important metric for the conservation and management of wild Atlantic salmon populations. Previously published primers for a male-specific gene were shown to be unreliable at determining sex due to the presence of deletions in the forward primer-binding site. A new forward primer, used in conjunction with the existing reverse primer, greatly improved reliability of the genetic test, correctly assigning gender in samples of known sex. Using DNA extracted from both contemporary and archive tissues, comparison between the two primer sets screened on collections of unknown sex ratio showed significant discrepancies in the number of males identified. The new primer will help improve the management and conservation of Atlantic salmon by providing accurate sex ratios for the setting of Conservation Limits.European Union Interreg France England Channel programme project ‘Salmonid Management Around the Channel’ (SAMARCH)UK Department of Environment, Farming and Rural Affairs (DEFRA

    Human mining activity across the ages determines the genetic structure of modern brown trout (Salmo trutta L.) populations.

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    PublishedJournal ArticleHumans have exploited the earth's metal resources for thousands of years leaving behind a legacy of toxic metal contamination and poor water quality. The southwest of England provides a well-defined example, with a rich history of metal mining dating to the Bronze Age. Mine water washout continues to negatively impact water quality across the region where brown trout (Salmo trutta L.) populations exist in both metal-impacted and relatively clean rivers. We used microsatellites to assess the genetic impact of mining practices on trout populations in this region. Our analyses demonstrated that metal-impacted trout populations have low genetic diversity and have experienced severe population declines. Metal-river trout populations are genetically distinct from clean-river populations, and also from one another, despite being geographically proximate. Using approximate Bayesian computation (ABC), we dated the origins of these genetic patterns to periods of intensive mining activity. The historical split of contemporary metal-impacted populations from clean-river fish dated to the Medieval period. Moreover, we observed two distinct genetic populations of trout within a single catchment and dated their divergence to the Industrial Revolution. Our investigation thus provides an evaluation of contemporary population genetics in showing how human-altered landscapes can change the genetic makeup of a species.Environment AgencyWest Country Rivers TrustUniversity of Exete

    On the role of magnetic reconnection in jet/accretion disk systems

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    The most accepted model for jet production is based on the magneto-centrifugal acceleration out off an accretion disk that surrounds the central source (Blandford & Payne, 1982). This scenario, however, does not explain, e.g., the quasi-periodic ejection phenomena often observed in different astrophysical jet classes. de Gouveia Dal Pino & Lazarian (2005) (hereafter GDPL) have proposed that the large scale superluminal ejections observed in microquasars during radio flare events could be produced by violent magnetic reconnection (MR) episodes. Here, we extend this model to other accretion disk systems, namely: active galactic nuclei (AGNs) and young stellar objects (YSOs), and also discuss its role on jet heating and particle acceleration.Comment: To be published in the IAU Highlights of Astronomy, Volume 15, XXVII IAU General Assembly, August 2009, Ian F. Corbett et al., eds., 201

    Ocean-bottom krill sex

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    For the first time the entire sequence of the mating behaviour of Antarctic krill (Euphausia superba) in the wild is captured on underwater video. This footage also provides evidence that mating can take place near the seafloor at depths of 400700 m. This observation challenges the generally accepted concept of the pelagic lifestyle of krill. The mating behaviour observed most closely resembles the mating behaviour reported for a decapod shrimp (Penaeus). The implications of the new observation are also discussed. © The Author 2011. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissionsoup.com2011This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.5), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. © © The Author 2011. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissionsoup.com

    Detection of non-melanoma skin cancer by in vivo fluorescence imaging with fluorocoxib A.

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    Non-melanoma skin cancer (NMSC) is the most common form of cancer in the US and its incidence is increasing. The current standard of care is visual inspection by physicians and/or dermatologists, followed by skin biopsy and pathologic confirmation. We have investigated the use of in vivo fluorescence imaging using fluorocoxib A as a molecular probe for early detection and assessment of skin tumors in mouse models of NMSC. Fluorocoxib A targets the cyclooxygenase-2 (COX-2) enzyme that is preferentially expressed by inflamed and tumor tissue, and therefore has potential to be an effective broadly active molecular biomarker for cancer detection. We tested the sensitivity of fluorocoxib A in a BCC allograft SCID hairless mouse model using a wide-field fluorescence imaging system. Subcutaneous allografts comprised of 1000 BCC cells were detectable above background. These BCC allograft mice were imaged over time and a linear correlation (R(2) = 0.8) between tumor volume and fluorocoxib A signal levels was observed. We also tested fluorocoxib A in a genetically engineered spontaneous BCC mouse model (Ptch1(+/-) K14-Cre-ER2 p53(fl/fl)), where sequential imaging of the same animals over time demonstrated that early, microscopic lesions (100 μm size) developed into visible macroscopic tumor masses over 11 to 17 days. Overall, for macroscopic tumors, the sensitivity was 88% and the specificity was 100%. For microscopic tumors, the sensitivity was 85% and specificity was 56%. These results demonstrate the potential of fluorocoxib A as an in vivo imaging agent for early detection, margin delineation and guided biopsies of NMSCs

    Historical processes and contemporary anthropogenic activities influence genetic population dynamics of Nassau grouper (Epinephelus striatus) within The Bahamas

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    This is the final version of the article. Available from Frontiers Media via the DOI in this record.Severe declines of endangered Nassau grouper (Epinephelus striatus) across The Bahamas and Caribbean have spurred efforts to improve their fisheries management and population conservation. The Bahamas is reported to hold the majority of fish spawning aggregations for Nassau grouper, however, the status and genetic population structure of fish within the country is largely unknown, presenting a major knowledge gap for their sustainable management. Between August 2014-February 2017, 464 individual Nassau grouper sampled from The Bahamas were genotyped using 15 polymorphic microsatellite loci to establish measures of population structure, genetic diversity and effective population size (N e ). Nassau grouper were characterized by mostly high levels of genetic diversity, but we found no evidence for geographic population structure. Microsatellite analyses revealed weak, but significant genetic differentiation of Nassau grouper throughout the Bahamian archipelago (Global FST 0.00236, p = 0.0001). Temporal analyses of changes in N e over the last 1,000 generations provide evidence in support of a pronounced historic decline in Bahamian Nassau grouper that appears to pre-date anthropogenic fishing activities. M-ratio results corroborate significant reductions in N e throughout The Bahamas, with evidence for population bottlenecks in three islands and an active fish spawning aggregation along with apparent signs of inbreeding at two islands. Current estimates of N e for Nassau grouper are considerably lower compared with historic levels. These findings represent important new contributions to our understanding of the evolutionary history, demographics and genetic connectivity of this endangered species, which are of critical importance for advancing their sustainable management.Molecular research was financially supported by the University of Exeter and research cruises were funded by the John G. Shedd Aquarium. Partial funding for KS was provided by the Shirley Oakes Butler Charitable Trust, Rotary Club of East Nassau and a private donation by I. de la Rocha

    Development of SNP markers derived from RAD sequencing for Atlantic salmon (Salmo salar L.) inhabiting the rivers of southern England

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    This is the final version. Available on open access from Springer via the DOI in this recordData availability: SNP genotypes are available upon request from the lead author.The rivers of the Hampshire Basin, southern England contain a genetically unique group of Atlantic salmon that have suffered dramatic declines in numbers over the last 40 years. Knowledge of levels and patterns of genetic diversity is essential for effective management of these vulnerable populations. Using restriction site-associated DNA sequencing (RADseq) data, we describe the development and characterisation of a panel of 94 single nucleotide polymorphism (SNP) loci for salmon from this region and investigate their applicability and variability in both target (i.e. southern English) and non-target populations. The SNP loci will be useful for population genetic and assignment studies on Atlantic salmon within the UK and beyond.European UnionSouthern Wate

    Atlantic salmon Salmo salar in the chalk streams of England are genetically unique.

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    This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordRecent research has identified genetic groups of Atlantic salmon Salmo salar that show association with geological and environmental boundaries. This study focuses on one particular subgroup of the species inhabiting the chalk streams of southern England, U.K. These fish are genetically distinct from other British and European S. salar populations and have previously demonstrated markedly low admixture with populations in neighbouring regions. The genetic population structure of S. salar occupying five chalk streams was explored using 16 microsatellite loci. The analysis provides evidence of the genetic distinctiveness of chalk-stream S. salar in southern England, in comparison with populations from non-chalk regions elsewhere in western Europe. Little genetic differentiation exists between the chalk-stream populations and a pattern of isolation by distance was evident. Furthermore, evidence of temporal stability of S. salar populations across the five chalk streams was found. This work provides new insights into the temporal stability and lack of genetic population sub-structuring within a unique component of the species' range of S. salar.This research was funded by the Game & Wildlife Conservation Trust and the Atlantic Salmon Trust, with additional support from the Salmon and Trout Association, the Westcountry Rivers Trust and the University of Exeter

    CASTNet: Community-Attentive Spatio-Temporal Networks for Opioid Overdose Forecasting

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    Opioid overdose is a growing public health crisis in the United States. This crisis, recognized as "opioid epidemic," has widespread societal consequences including the degradation of health, and the increase in crime rates and family problems. To improve the overdose surveillance and to identify the areas in need of prevention effort, in this work, we focus on forecasting opioid overdose using real-time crime dynamics. Previous work identified various types of links between opioid use and criminal activities, such as financial motives and common causes. Motivated by these observations, we propose a novel spatio-temporal predictive model for opioid overdose forecasting by leveraging the spatio-temporal patterns of crime incidents. Our proposed model incorporates multi-head attentional networks to learn different representation subspaces of features. Such deep learning architecture, called "community-attentive" networks, allows the prediction of a given location to be optimized by a mixture of groups (i.e., communities) of regions. In addition, our proposed model allows for interpreting what features, from what communities, have more contributions to predicting local incidents as well as how these communities are captured through forecasting. Our results on two real-world overdose datasets indicate that our model achieves superior forecasting performance and provides meaningful interpretations in terms of spatio-temporal relationships between the dynamics of crime and that of opioid overdose.Comment: Accepted as conference paper at ECML-PKDD 201

    Insulin resistance:Impact on therapeutic developments in diabetes

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    Insulin resistance has a broad pathogenic impact affecting metabolic, cardio-renal and other disease areas. Extensive studies to dissect the mechanisms of insulin resistance have provided valuable insights to shape current clinical awareness and advance therapeutic practice. However, the development of direct interventions against insulin resistance has been hindered by its complex and highly variable presentations, especially in type 2 diabetes. Among glucose-lowering agents, metformin and thiazolidinediones provide cellular actions that counter some effects of insulin resistance: reduced glucotoxicity and weight-lowering with antidiabetic therapies also improve insulin action, except that endogenously- or exogenously-created hyperinsulinaemia may partially compromise these benefits. Increasing awareness of the pervasiveness and damaging ramifications of insulin resistance heightens the need for more specifically targeted and more effective therapies
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