124 research outputs found

    Habitat-mediated size selection in endangered Atlantic salmon fry: selectional restoration assessment

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    Preservation of adaptive variation is a top priority of many species restoration programs, but most restoration activities are conducted without direct knowledge of selection that might foster or impair adaptation and restoration goals. In this study, we quantified geographic variation in selection on fry size of endangered Atlantic salmon (Salmo salar) during the 6-week period immediately following stocking in the wild. We also used a model selection approach to assess whether habitat variables influence patterns of such selection. We found evidence for significant size-selection in five out of six selection trials. Interestingly, the strength and pattern of selection varied extensively among sites, and model selection suggested that this variation in phenotypic selection was related to geographic variation in the presence of large woody debris and the slope of the stream gradient. The strong selection differentials we observed should be a concern for endangered salmon restoration, whether they reflect natural processes and an opportunity to maintain adaptation, or an indicator of the potentially deleterious phenotypic consequences of hatchery practices

    Semienzymatic cyclization of disulfide-rich peptides using sortase A

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    Background: Sortase A (SrtA) is a transpeptidase capable of catalyzing the formation of amide bonds. Results: SrtA was used to backbone-cyclize disulfide-rich peptides, including kalata B1, -conotoxin Vc1.1, and SFTI-1. Conclusion: SrtA-mediated cyclization is applicable to small disulfide-rich peptides. Significance: SrtA-mediated cyclization is an alternative to native chemical ligation for the cyclization of small peptides of therapeutic interest

    Increased Resting-State Functional Connectivity in Obese Adolescents; A Magnetoencephalographic Pilot Study

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    BACKGROUND: Obesity is not only associated with metabolic abnormalities, but also with cognitive dysfunction and changes in the central nervous system. The present pilot study was carried out to investigate functional connectivity in obese and non-obese adolescents using magnetoencephalography (MEG). METHODOLOGY/PRINCIPAL FINDINGS: Magnetoencephalographic recordings were performed in 11 obese (mean BMI 38.8+/-4.6 kg/m(2)) and 8 lean (mean BMI 21.0+/-1.5 kg/m(2)) female adolescents (age 12-19 years) during an eyes-closed resting-state condition. From these recordings, the synchronization likelihood (SL), a common method that estimates both linear and non-linear interdependencies between MEG signals, was calculated within and between brain regions, and within standard frequency bands (delta, theta, alpha1, alpha2, beta and gamma). The obese adolescents had increased synchronization in delta (0.5-4 Hz) and beta (13-30 Hz) frequency bands compared to lean controls (P(delta total) = 0.001; P(beta total) = 0.002). CONCLUSIONS/SIGNIFICANCE: This study identified increased resting-state functional connectivity in severe obese adolescents. Considering the importance of functional coupling between brain areas for cognitive functioning, the present findings strengthen the hypothesis that obesity may have a major impact on human brain function. The cause of the observed excessive synchronization is unknown, but might be related to disturbed motivational pathways, the recently demonstrated increase in white matter volume in obese subjects or altered metabolic processes like hyperinsulinemia. The question arises whether the changes in brain structure and communication are a dynamic process due to weight gain and whether these effects are reversible or not

    Social impacts as a function of place change

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    This paper argues that both impacts felt by and attitudes to tourism are a function of place change. Destinations are comprised of three types of place: tourism, non-tourism and shared. It is believed attitudes are generally positive when stasis exists among the three types, but deteriorate during periods of rapid place change. Likewise, impacts are felt when place changes, especially when non-tourism place is transformed into either shared or tourism place. This proposition is tested through a meta-analysis of more than 90 journal articles examining social impacts of tourism. Nine types of place change were identiïŹed as well as a relationship between place change and lifecycle stage

    Uranium mobility in organic matter-rich sediments: A review of geological and geochemical processes

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    Uranium (U) is of enormous global importance because of its use in energy generation, albeit with potential environmental legacies. While naturally occurring U is widespread in the Earth's crust at concentrations of ~1 to 3 ppm, higher concentrations can be found, includingwithin organicmatter (OM)-rich sediments, leading to economic extraction opportunities. The primary determinants of U behaviour in ore systems are pH, Eh, U oxidation state (U(IV), U(VI)) and the abundance of CO3 2– ions. The concentration/availability and interrelationships among such determinants vary, and the solubility and mobility of ions (e.g. OH-, CO3 2–, PO4 3-, SiO4 4-, SO4 2-) that compete for U (primarily as U(VI)) will also influence the mobility of U. In addition, the presence of OM can influence U mobility and fate by the degree of OMsorption to mineral surfaces (e.g. Fe- and Si- oxides and hydroxides). Within solid-phase OM, microbes can influence U oxidation state and U stability through direct enzymatic reduction, biosorption, biomineralisation and bioaccumulation. The biogenic UO2 product is, however, reported to be readily susceptible to reoxidation and therefore more likely remobilised over longer time periods. Thus several areas of uncertainty remain with respect to factors contributing to U accumulation, stability and/or (re)mobilisation. To address these uncertainties, this paper reviews U dynamics at both geological and molecular scales. Here we identify U-OMbond values that are in agreement, relatively strong, independent from ionic strength and which may facilitate either U mobilisation or immobilisation, depending on environmental conditions. We also examine knowledge gaps in the literature, with U-OM solubility data generally lacking in comparison to data for U sorption and dissolution, and little information available on multi-component relationships, such as UOM-V (V as vanadate). Furthermore, the capability ofOMto influence the oxidation state of U at near surface conditions remains unclear, as it can be postulated that electron shuttling by OM may contribute to changes in U redox state otherwise mediated by bacteria. Geochemical modelling of the environmental mobility of U will require incorporation of data from multi-corporation studies, as well as from studies of U-OM microbial interactions, all of which are considered in this review

    A realist analysis of hospital patient safety in Wales:Applied learning for alternative contexts from a multisite case study

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    Background: Hospital patient safety is a major social problem. In the UK, policy responses focus on the introduction of improvement programmes that seek to implement evidence-based clinical practices using the Model for Improvement, Plan-Do-Study-Act cycle. Empirical evidence that the outcomes of such programmes vary across hospitals demonstrates that the context of their implementation matters. However, the relationships between features of context and the implementation of safety programmes are both undertheorised and poorly understood in empirical terms. Objectives: This study is designed to address gaps in conceptual, methodological and empirical knowledge about the influence of context on the local implementation of patient safety programmes. Design: We used concepts from critical realism and institutional analysis to conduct a qualitative comparative-intensive case study involving 21 hospitals across all seven Welsh health boards. We focused on the local implementation of three focal interventions from the 1000 Lives+ patient safety programme: Improving Leadership for Quality Improvement, Reducing Surgical Complications and Reducing Health-care Associated Infection. Our main sources of data were 160 semistructured interviews, observation and 1700 health policy and organisational documents. These data were analysed using the realist approaches of abstraction, abduction and retroduction. Setting: Welsh Government and NHS Wales. Participants: Interviews were conducted with 160 participants including government policy leads, health managers and professionals, partner agencies with strategic oversight of patient safety, advocacy groups and academics with expertise in patient safety. Main outcome measures: Identification of the contextual factors pertinent to the local implementation of the 1000 Lives+ patient safety programme in Welsh NHS hospitals. Results: An innovative conceptual framework harnessing realist social theory and institutional theory was produced to address challenges identified within previous applications of realist inquiry in patient safety research. This involved the development and use of an explanatory intervention–context–mechanism–agency–outcome (I-CMAO) configuration to illustrate the processes behind implementation of a change programme. Our findings, illustrated by multiple nested I-CMAO configurations, show how local implementation of patient safety interventions are impacted and modified by particular aspects of context: specifically, isomorphism, by which an intervention becomes adapted to the environment in which it is implemented; institutional logics, the beliefs and values underpinning the intervention and its source, and their perceived legitimacy among different groups of health-care professionals; and the relational structure and power dynamics of the functional group, that is, those tasked with implementing the initiative. This dynamic interplay shapes and guides actions leading to the normalisation or the rejection of the patient safety programme. Conclusions: Heightened awareness of the influence of context on the local implementation of patient safety programmes is required to inform the design of such interventions and to ensure their effective implementation and operationalisation in the day-to-day practice of health-care teams. Future work is required to elaborate our conceptual model and findings in similar settings where different interventions are introduced, and in different settings where similar innovations are implemented. Funding: The National Institute for Health Research Health Services and Delivery Research programme
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