54 research outputs found

    Investigating the foraging ecology and energy requirements of a seabird population increasing in an intensely exploited marine environment

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    Their high energetic demands make seabirds sensitive to changes in prey availability, which is often reflected in their diet and energetic expenditure during breeding. Populations of the three seabirds endemic to southern Africa's Benguela upwelling ecosystem that rely on small pelagic fish have decreased dramatically over the last decade. In contrast, the population of the greater crested tern Thalasseus bergii has increased. To understand these conflicting trends, I investigated the foraging ecology and energy requirements of greater crested tern breeding in the Western Cape, South Africa. Diet was assessed by a novel non-invasive methodology developed in this study, using digital photography. More than 24,000 prey items from at least 51 different prey taxa were identified, with 34 new prey species recorded, revealing a high degree of foraging plasticity for this seabird. Greater crested terns rely mainly on anchovy Engraulis encrasicolus (65%), which averaged 84 mm long. Prey composition differed significantly between breeding stages, with anchovy especially dominant at the onset of the breeding period and the diet becoming more variable as the season progressed. Time-energy models for breeding terns were built based on activity budgets collected from non-invasive video-recordings and focal observations. Foraging trips were significantly longer during incubation than the chick provisioning stages, and feeding rates doubled from early to late chick provisioning. This study illustrated a steady increase in energy needs of adults throughout the breeding season, due to their increased foraging effort to meet chick energy needs. In comparison to other Benguela endemic seabirds that also rely on small pelagic fish, terns displayed substantially lower energy requirements at both individual and population levels. I also explored the benefits underlying interactions within mixed-species aggregations by investigating the costs induced by kleptoparasitism between mixed colonies of greater crested terns and Hartlaub's gulls Chroicocephalus hartlaubii and colonies with greater crested terns alone. Video-recordings coupled with focal observations showed that terns suffer direct costs to chick provisioning rates and indirect costs through energy expenditure in a mixed-species colony, suggesting that these breeding assemblages may be a form of parasitism rather than a mutualistic association. Despite the detrimental effects of interspecific kleptoparasitism, the marked foraging plasticity and low energetic requirements of greater crested terns, described in this study, coupled with specific life history traits such as low fidelity to breeding sites and extended post-fledging care, are key factors that allow this species to cope with changes in the availability and abundance of their main prey. Understanding species-specific behavioural responses to ecosystem variations in the Benguela upwelling system is vital for assessing the impact of commercial fisheries on seabird populations and fish stocks. Finally, the implementation of the method developed in this study, in long-term monitoring programmes, may provide crucial knowledge for conservation plans and key input to realising an ecosystem approach to fisheries management

    KNOWLEDGE AND VIEWPOINTS ON THE EFFECTS OF CORRUPTION ON HEALTHCARE: A SURVEY CONDUCTED AMONG STUDENTS OF PALERMO UNIVERSITY MEDICAL SCHOOL, ITALY

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    Corruption affects healthcare effectiveness and efficiency and limits equity in access to health services. Aim of the survey was to document knowledge and viewpoints on the impact of corruption on healthcare system in a sample of students attending pre-lauream healthcare professional courses at Palermo University Medical school and to evaluate any improvement in their awareness on this topic after a dedicated multidisciplinary educational intervention. An anonymous questionnaire was administered to students before and after the intervention. Absolute and relative frequency of correct and incorrect answers was computed. Chi-squared test was used to compare answers given before and after the educational intervention. Approximately less than a quarter of the respondents were able to correctly estimate impact of corruption, inappropriateness and waste in healthcare on NHS. The study documented how improving students\u2019 knowledge of the impact of corruption in the healthcare system could represent a possible strategy to prevent corruption in healthcare

    Functional complementation of sir2Δ yeast mutation by the human orthologous gene SIRT1

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    Sirtuins, class III histone deacetylases, are proteins homologous to the yeast protein Sir2p. Mammalian Sirt1 has been shown to be involved in energy metabolism, brain functions, inflammation and aging through its deacetylase activity, acting on both histone and non-histone substrates. In order to verify whether Sirt1 can replace Sir2p in the yeast cells, we expressed the full-length human Sirt1 protein in S.cerevisiae sir2Δ mutant strain. The structure of chromatin is basically maintained from yeast to human. Thus, yeast chromatin is a favourable environment to evaluate, inhibit or activate an ectopic histone deacetylase activity in an in vivo substrate. Mutant sir2Δ shows a series of different phenotypes, all dependent on the deacetylase activity of Sir2p. We analyzed the three silent loci where normally Sir2p acts: ribosomal DNA, telomeres and the mating type loci. Moreover, we verified extrachromosomal ribosomal DNA circles production and histone hyperacetylation levels, typical marks of sir2Δ strains. By strong SIRT1 overexpression in sir2Δ cells, we found that specific molecular phenotypes of the mutant revert almost to a wild-type condition. In particular, transcriptional silencing at rDNA was restored, extrachromosomal rDNA circles formation was repressed and histone acetylation at H3K9 and H4K16 decreased. The complementation at the other studied loci: HM loci, telomere and sub-telomere does not occur. Overall, our observations indicate that: i) SIRT1 gene is able to complement different molecular phenotypes of the sir2Δ mutant at rDNA ii) the in vivo screening of Sirt1 activity is possible in yeast.This work was partially supported by: the Istituto Pasteur-Fondazione Cenci Bolognetti, Università di Roma La Sapienza (http:// www.istitutopasteur.it/)and by the Epigenomics Flagship Project EpiGen, the Italian Ministry of Education and Research, National Research Council (http:// www.epigen.it/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    ASL_Weeks_ANOVA_colony.csv

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    csv file for ANOVA analysi

    NMDS2.csv

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    csv file for NMDS analysi

    Foraging plasticity in seabirds: a non-invasive study of the diet of greater crested terns breeding in the Benguela Region

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    We investigated the diet of an increasing population of greater crested terns <i>Thalasseus bergii</i> in the Western Cape, South Africa, during three successive breeding seasons (2013 to 2015), when populations of other seabirds feeding on small pelagic schooling fish in the region were decreasing

    ASL_Years_ANOVA.csv

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    csv file for yearly anova analysi

    Gaglio et al. ANOVA.rtf

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    R Script for ANOVA analysi

    Gaglio et al. GAM.rtf

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    R script for GAM Mode
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