1,101 research outputs found

    Molecular epidemiology of NDM-1-producing Enterobacteriaceae and Acinetobacter baumannii isolates from Pakistan

    Get PDF
    The molecular epidemiology of 66 NDM-producing isolates from 2 Pakistani hospitals was investigated, with their genetic relatedness determined using repetitive sequence-based PCR (Rep-PCR). PCR-based replicon typing and screening for antibiotic resistance genes encoding carbapenemases, other β-lactamases, and 16S methylases were also performed. Rep-PCR suggested a clonal spread of Enterobacter cloacae and Escherichia coli. A number of plasmid replicon types were identified, with the incompatibility A/C group (IncA/C) being the most common (78%). 16S methylase-encoding genes were coharbored in 81% of NDM-producing Enterobacteriaceae. Copyrigh

    Biological control of invasive climbing plants in South Africa

    Get PDF
    Vines and other climbing plants typically invest their resources into growth at the expense of accumulating self-supporting biomass. Adaptive traits that have arisen because of the life history needs of climbing species, such as rapid and extensive growth, as well as resilience to physical damage, make these plants highly competitive. Introduced climbing species therefore have the potential to be particularly damaging in novel ranges where they escape pressure from natural enemies. In South Africa, invasive climbing species negatively influence biodiversity and plant-community structure, and as conventional management is often difficult, biological control (biocontrol) is viewed as the only viable long-term control method. This paper consolidates the work done on biocontrol programmes against climbing species in South Africa, including Anredera cordifolia (Ten.) Steenis (Basellaceae), Cardiospermum grandiflorum Sw. (Sapindaceae), Dolichandra unguis-cati (L.) L.G.Lohmann (Bignoniaceae) and Pereskia aculeata Miller (Cactaceae). To date, these programmes have investigated some 27 potential biocontrol agents, of which nine have been approved for release in the country. Since 2010, three new agents have been introduced, and considerable progress made with post-release evaluations of all the introduced agents. Some positive results have been achieved, most notably the successful reduction in seed set of C. grandiflorum due to Cissanthonomus tuberculipennis Hustache (Curculionidae), but considerable variation in efficacy over time and between infestations has been recorded for many of the other agents. Further work may help explain the factors limiting success, leading to improved control, but in some cases, such as for A. cordifolia, new biocontrol agents should be considered

    Negotiating stance within discourses of class: reactions to Benefits Street

    Get PDF
    In this article, we examine the way that audiences respond to particular representations of poverty. Using clips from the Channel 4 television programme Benefits Street we conducted focus groups in four locations across the UK, working with people from different socioeconomic backgrounds who had different experiences with the benefits system. Benefits Street (2014) is an example of reality television where members of the public are followed by film crews as they perform everyday tasks and routines. Our choice to focus on this particular programme was prompted by the huge media response that it received when it was broadcast; Benefits Street generated 950 complaints to regulatory watchdog Ofcom (2014) and was referred to as ‘poverty porn’ (Clark, 2014). We focus on the way that viewers of this programme produce assessments of those on benefits, analysing the discursive strategies used by our participants when evaluating representations of those on benefits. Specifically, we consider how the participants in our study construct their own stance and attribute stance to others through naming and agency practices, the negotiation of opinion, and stake inoculation. We invited our participants to judge the people they saw on screen, but they went beyond this. They used clips of the programme as stimuli to collaboratively construct an overarchingly-negative stereotype of those on benefits. We conclude that Benefits Street is not just an entertainment programme, but is rather a site for ideological construction and the perpetuation of existing stereotypes about benefit claimants. The programme (and others like it) invites negative evaluations of those on benefits and is thus a worthy site for critical linguistic analysis

    The impact of ocean acidification on the functional morphology of foraminifera

    Get PDF
    This work was supported by the NERC UK Ocean Acidification Research Programme grant NE/H017445/1. WENA acknowledges NERC support (NE/G018502/1). DMP received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.Culturing experiments were performed on sediment samples from the Ythan Estuary, N. E. Scotland, to assess the impacts of ocean acidification on test surface ornamentation in the benthic foraminifer Haynesina germanica. Specimens were cultured for 36 weeks at either 380, 750 or 1000 ppm atmospheric CO2. Analysis of the test surface using SEM imaging reveals sensitivity of functionally important ornamentation associated with feeding to changing seawater CO2 levels. Specimens incubated at high CO2 levels displayed evidence of shell dissolution, a significant reduction and deformation of ornamentation. It is clear that these calcifying organisms are likely to be vulnerable to ocean acidification. A reduction in functionally important ornamentation could lead to a reduction in feeding efficiency with consequent impacts on this organism’s survival and fitness.Publisher PDFPeer reviewe

    Cortical microstructure in young onset Alzheimer's disease using neurite orientation dispersion and density imaging.

    Get PDF
    Alzheimer's disease (AD) is associated with extensive alterations in grey matter microstructure, but our ability to quantify this in vivo is limited. Neurite orientation dispersion and density imaging (NODDI) is a multi-shell diffusion MRI technique that estimates neuritic microstructure in the form of orientation dispersion and neurite density indices (ODI/NDI). Mean values for cortical thickness, ODI, and NDI were extracted from predefined regions of interest in the cortical grey matter of 38 patients with young onset AD and 22 healthy controls. Five cortical regions associated with early atrophy in AD (entorhinal cortex, inferior temporal gyrus, middle temporal gyrus, fusiform gyrus, and precuneus) and one region relatively spared from atrophy in AD (precentral gyrus) were investigated. ODI, NDI, and cortical thickness values were compared between controls and patients for each region, and their associations with MMSE score were assessed. NDI values of all regions were significantly lower in patients. Cortical thickness measurements were significantly lower in patients in regions associated with early atrophy in AD, but not in the precentral gyrus. Decreased ODI was evident in patients in the inferior and middle temporal gyri, fusiform gyrus, and precuneus. The majority of AD-related decreases in cortical ODI and NDI persisted following adjustment for cortical thickness, as well as each other. There was evidence in the patient group that cortical NDI was associated with MMSE performance. These data suggest distinct differences in cortical NDI and ODI occur in AD and these metrics provide pathologically relevant information beyond that of cortical thinning

    Advancing impact prediction and hypothesis testing in invasion ecology using a comparative functional response approach

    Get PDF
    Invasion ecology urgently requires predictive methodologies that can forecast the ecological impacts of existing, emerging and potential invasive species. We argue that many ecologically damaging invaders are characterised by their more efficient use of resources. Consequently, comparison of the classical ‘functional response’ (relationship between resource use and availability) between invasive and trophically analogous native species may allow prediction of invader ecological impact. We review the utility of species trait comparisons and the history and context of the use of functional responses in invasion ecology, then present our framework for the use of comparative functional responses. We show that functional response analyses, by describing the resource use of species over a range of resource availabilities, avoids many pitfalls of ‘snapshot’ assessments of resource use. Our framework demonstrates how comparisons of invader and native functional responses, within and between Type II and III functional responses, allow testing of the likely population-level outcomes of invasions for affected species. Furthermore, we describe how recent studies support the predictive capacity of this method; for example, the invasive ‘bloody red shrimp’ Hemimysis anomala shows higher Type II functional responses than native mysids and this corroborates, and could have predicted, actual invader impacts in the field. The comparative functional response method can also be used to examine differences in the impact of two or more invaders, two or more populations of the same invader, and the abiotic (e.g. temperature) and biotic (e.g. parasitism) context-dependencies of invader impacts. Our framework may also address the previous lack of rigour in testing major hypotheses in invasion ecology, such as the ‘enemy release’ and ‘biotic resistance’ hypotheses, as our approach explicitly considers demographic consequences for impacted resources, such as native and invasive prey species. We also identify potential challenges in the application of comparative functional responses in invasion ecology. These include incorporation of numerical responses, multiple predator effects and trait-mediated indirect interactions, replacement versus non-replacement study designs and the inclusion of functional responses in risk assessment frameworks. In future, the generation of sufficient case studies for a meta-analysis could test the overall hypothesis that comparative functional responses can indeed predict invasive species impact

    Current- and Wave-Generated Bedforms on Mixed Sand–Clay Intertidal Flats:A New Bedform Phase Diagram and Implications for Bed Roughness and Preservation Potential

    Get PDF
    The effect of bedforms on frictional roughness felt by the overlying flow is crucial to the regional modelling of estuaries and coastal seas. Bedforms are also a key marker of palaeoenvironments. Experiments have shown that even modest biotic and abiotic cohesion in sand inhibits bedform formation, modifies bedform size, and slows bedform development, but this has rarely been tested in nature. The present study used a comprehensive dataset recorded over a complete spring–neap cycle on an intertidal flat to investigate bedform dynamics controlled by a wide range of wave and current conditions, including the effects of wave–current angle and bed cohesion. A detailed picture of different bedform types and their relationship to the flow, be they equilibrium, non-equilibrium, or relict, was produced, and captured in a phase diagram that integrates wave-dominated, current-dominated, and combined wave–current bedforms. This bedform phase diagram incorporates a substantially wider range of flow conditions than previous phase diagrams, including bedforms related to near-orthogonal wave–current angles, such as ladderback ripples. Comparison with laboratory-derived bedform phase diagrams indicates that washed-out ripples, lunate interference ripples and upper-stage plane beds replace the subaqueous dune field; such bedform distributions may be a key characteristic of intertidal flats. The field data also provide a means of predicting the dimensions of these bedforms, which can be transferred to other areas and grain sizes. We show that an equation for the prediction of equilibrium bedform size is sufficient to predict the roughness, even though the bedforms are highly variable in character and only in equilibrium with the flow for approximately half the time. Whilst the effect of cohesive clay is limited under more active spring conditions, clay does play a role in reducing the bedform dimensions under more quiescent neap conditions. We also investigated which combinations of waves, currents, and bed clay contents in the intertidal zone have the highest potential for bedform preservation in the geological record. This shows that combined wave–current bedforms have the lowest preservation potential and equilibrium current ripples have the highest preservation potential, even in the presence of moderate and storm waves. Hence, the absence of wave ripples and combined-flow bedforms and their primary stratification in sedimentary successions cannot be taken as evidence that waves were absent at the time of deposition

    Pulmonary Abnormalities and Carotid Atherosclerosis in Ex-Smokers without Airflow Limitation.

    Get PDF
    Abstract It is well-established that COPD patients have a burden of vascular disease that cannot be fully-explained by smoking history but the mechanistic links between atherosclerosis and pulmonary disease in COPD patients are not well-understood. Moreover, in ex-smokers without symptoms or other evidence of COPD, subclinical pulmonary and vascular disease, although potentially present, has not been described or evaluated. Hence our aim was to use sensitive three-dimensional (3D) pulmonary and carotid imaging to quantify pulmonary airway/parenchyma abnormalities and atherosclerosis in ex-smokers without airflow limitation or symptoms consistent with COPD. We evaluated 61 subjects without airflow limitation including 34 never- (72 ± 6 years) and 27 ex-smokers (73 ± 9 years), who provided written informed consent to spirometry, plethysmography, (3)He magnetic resonance imaging (MRI) and carotid ultrasound (US) and, for ex-smokers alone, thoracic X-ray computed tomography (CT). Ex-smokers had significantly greater (3)He ventilation defect percent (VDP = 7%, p = 0.001) and carotid total plaque volume (TPV = 250 mm(3), p = 0.002) than never-smokers, although there were no significant differences for spirometry or plethysmography, and CT airway and emphysema measurements were normal. There were univariate relationships for (3)He VDP with carotid intima media thickness (IMT, r = 0.42, p = 0.004), TPV (r = 0.41, p = 0.006) and vessel wall volume (VWV, r = 0.40, p = 0.007). Multivariate models that included age, BMI, FEV1, DLCO and VDP showed that only VDP significantly predicted IMT (β = 0.41, p = 0.001), VWV (β = 0.45, p = 0.003) and TPV (β = 0.38, p = 0.005). In summary, there was imaging evidence of mild airways disease and carotid plaque burden that were related and significantly greater in ex-smokers without airflow limitation than in never-smokers
    • …
    corecore