281 research outputs found

    Trophic ecology of common elasmobranchs exploited by artisanal shark fisheries off south-western Madagascar

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    Knowledge of the trophic ecology and interactions of marine top predators is fundamental for understanding community structure and dynamics as well as ecosystem function. We examined the feeding relationships of 4 heavily exploited elasmobranchs caught in coastal artisanal shark fisheries in south-western Madagascar in 2009 and 2010—Sphyrna lewini, Loxodon macrorhinus, Carcharhinus falciformis and Rhynchobatus djiddensis—using stable isotope (ή15N and ή13C) analysis. Relative trophic position (indicated by ή15N) and foraging location (indicated by ή13C) differed among species. Isotopic niche width was highly variable: more pelagic species, such as S. lewini and C. falciformis, had the broadest isotopic niches while the benthic R. djiddensis had the narrowest. A high percentage of niche overlap occurred between R. djiddensis and 2 of the species, C. falciformis (93.2%) and L. macrorhinus (73.2%), and to a lesser extent S. lewini (13.3%). Relative trophic position of S. lewini significantly increased with size, suggesting a dietary shift with age. Sex differences in ή15N values were observed in L. macrorhinus, suggesting intraspecific niche partitioning. Variation in stable isotope values among these 4 highly exploited elasmobranch species indicates trophic structuring, likely driven by differences in diet and habitat use as well as by size and sex. This study provides the first baseline information on the trophic ecology of elasmobranchs caught in artisanal fisheries from south-western Madagascar

    The population genomic structure of green turtles (<i>Chelonia mydas</i>) suggests a warm-water corridor for tropical marine fauna between the Atlantic and Indian oceans during the last interglacial

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    The occasional westward transport of warm water of the Agulhas Current, “Agulhas leakage”, around southern Africa has been suggested to facilitate tropical marine connectivity between the Atlantic and Indian oceans, but the “Agulhas leakage” hypothesis does not explain the signatures of eastward gene flow observed in many tropical marine fauna. We investigated an alternative hypothesis: the establishment of a warm-water corridor during comparatively warm interglacial periods. The “warm-water corridor” hypothesis was investigated by studying the population genomic structure of Atlantic and Southwest Indian Ocean green turtles (N = 27) using 12,035 genome-wide single nucleotide polymorphisms (SNPs) obtained via ddRAD sequencing. Model-based and multivariate clustering suggested a hierarchical population structure with two main Atlantic and Southwest Indian Ocean clusters, and a Caribbean and East Atlantic sub-cluster nested within the Atlantic cluster. Coalescent-based model selection supported a model where Southwest Indian Ocean and Caribbean populations diverged from the East Atlantic population during the transition from the last interglacial period (130–115 thousand years ago; kya) to the last glacial period (115–90 kya). The onset of the last glaciation appeared to isolate Atlantic and Southwest Indian Ocean green turtles into three refugia, which subsequently came into secondary contact in the Caribbean and Southwest Indian Ocean when global temperatures increased after the Last Glacial Maximum. Our findings support the establishment of a warm-water corridor facilitating tropical marine connectivity between the Atlantic and Southwest Indian Ocean during warm interglacials

    Discussion of “Auguste Graeff: Dam Designer and Hydraulic Engineer” by Willi H. Hager and Corrado Gisonni

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    The work of Auguste Graeff is rarely acknowledged for his true contribution to hydraulic engineering and structures. Herein further information on Graeff and his co-worker Emile Delocre are presented together with the influence of their work in France and overseas, and several curved gravity dams built around Saint-Etienne based upon the Gouffre d'Enfer dam design. Altogether Auguste Graeff and Emile Delocre had a significant influence on gravity dam design in France and overseas

    The Note synthesis and crystal structure of a cerium(III) complex of 2,6-bis [2-formylphenoxymethyl]pyridine

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    Abstract The synthesis and X-ray crystal structure of a ten-coordinate cerium(III) nitrate complex of 2,6-bis[2-formylphenoxymethyl]-pyridine is reported

    GP/GPN partner* perspectives on clinical placements for student nurses in general practice: can a community of practice help to change the prevailing culture within general practice?

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    Background: The UK Government document 5 year forward view describes the need to move chronic disease management from secondary to primary care, which will require a significant increase in the numbers of General Practice Nurses (GPNs). Until recently, there has been no specific recruitment strategy to address this increased need. In recent times, a number of solutions have been suggested to address this impending GPN recruitment crisis. For example, Health Education England (HEE) commission General Practitioners (GPs), who are members of the Advanced Training Practice Scheme (ATPS), to provide placements for student nurses within general practice. Methods: A descriptive qualitative study was undertaken, in which data were collected using semi-structured interviews with 16 GPs and 2 GPN partners∗. Qualitative analysis used a framework approach and themes were cross-checked within the team and member checking was undertaken with a convenience sample of GPs. The research had ethical approval and anonymity and confidentiality were maintained. Results: From the GP perspective, there were two key themes that emerged from the data. The first theme of 'fishing in the same small pond' included succession planning for the general practice workforce, the 'merry go round' of poaching staff from other practices, and the myths and misunderstandings that have grown up around general practice nursing. The second theme, 'growing your own', looked at the impact of the student nurse placements as a means to address the crisis in GPN recruitment. There was recognition of the need for cultural change in the way that GPNs are recruited, and that the ATPS was one way of helping to achieve that change. There were however a number of challenges to sustaining this cultural shift, such as the financial constrains placed upon the GP practice, and the need to function as a 'small business'. Conclusions: Despite all the challenges, the evidence is that, through the Community of Practice (CoP), the ATPS scheme is beginning to 'bear fruit', and there is a subtle but discernible move by GPs from a 'why would we?' to 'why wouldn't we?' invest in education and training for nurses in general practice. N.B. The term GPN partner∗denotes a GPN who is a 'full partner' in the practice business, holding the same NHS contracts and the same status as a GP. For the purposes of the paper itself, the term GP will be used to denote both types of partner

    Coxsackievirus B3 infects and disrupts human induced-pluripotent stem cell derived brain-like endothelial cells

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    Coxsackievirus B3 (CVB3) is a significant human pathogen that is commonly found worldwide. CVB3 among other enteroviruses, are the leading causes of aseptic meningo-encephalitis which can be fatal especially in young children. How the virus gains access to the brain is poorly-understood, and the host-virus interactions that occur at the blood-brain barrier (BBB) is even less-characterized. The BBB is a highly specialized biological barrier consisting primarily of brain endothelial cells which possess unique barrier properties and facilitate the passage of nutrients into the brain while restricting access to toxins and pathogens including viruses. To determine the effects of CVB3 infection on the BBB, we utilized a model of human induced-pluripotent stem cell-derived brain-like endothelial cells (iBECs) to ascertain if CVB3 infection may alter barrier cell function and overall survival. In this study, we determined that these iBECs indeed are susceptible to CVB3 infection and release high titers of extracellular virus. We also determined that infected iBECs maintain high transendothelial electrical resistance (TEER) during early infection despite possessing high viral load. TEER progressively declines at later stages of infection. Interestingly, despite the high viral burden and TEER disruptions at later timepoints, infected iBEC monolayers remain intact, indicating a low degree of late-stage virally-mediated cell death, which may contribute to prolonged viral shedding. We had previously reported that CVB3 infections rely on the activation of transient receptor vanilloid potential 1 (TRPV1) and found that inhibiting TRPV1 activity with SB-366791 significantly limited CVB3 infection of HeLa cervical cancer cells. Similarly in this study, we observed that treating iBECs with SB-366791 significantly reduced CVB3 infection, which suggests that not only can this drug potentially limit viral entry into the brain, but also demonstrates that this infection model could be a valuable platform for testing antiviral treatments of neurotropic viruses. In all, our findings elucidate the unique effects of CVB3 infection on the BBB and shed light on potential mechanisms by which the virus can initiate infections in the brain
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