354 research outputs found

    Photoreceptor perturbation around subretinal drusenoid deposits as revealed by adaptive optics scanning laser ophthalmoscopy

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    PURPOSE: To describe the microscopic structure of photoreceptors impacted by subretinal drusenoid deposits, also called pseudodrusen, an extracellular lesion associated with age-related macular degeneration (AMD), using adaptive optics scanning laser ophthalmoscopy (AOSLO). DESIGN: Observational case series. METHODS: We recruited 53 patients with AMD and 10 age-similar subjects who had normal retinal health. All subjects underwent color fundus photography, infrared reflectance, red-free reflectance, autofluorescence, and spectral-domain optical coherence tomography (OCT). Subretinal drusenoid deposits were classified by a 3-stage OCT-based grading system. Lesions and surrounding photoreceptors were examined by AOSLO. RESULTS: Subretinal drusenoid deposits were found in 26 eyes of 13 patients with AMD and imaged by AOSLO and spectral-domain OCT in 18 eyes (n = 342 lesions). Spectral-domain OCT showed subretinal drusenoid deposits as highly reflective material accumulated internal to the retinal pigment epithelium. AOSLO revealed that photoreceptor reflectivity was qualitatively reduced by stage 1 subretinal drusenoid deposits and was greatly reduced by stage 2. AOSLO presented a distinct structure in stage 3, a hyporeflective annulus consisting of deflected, degenerated or absent photoreceptors. A central core with a reflectivity superficially resembling photoreceptors is formed by the lesion material itself. A hyporeflective gap in the photoreceptor ellipsoid zone on either side of this core shown in spectral-domain OCT corresponded to the hyporeflective annulus seen by AOSLO. CONCLUSIONS: AOSLO and multimodal imaging of subretinal drusenoid deposits indicate solid, space-filling lesions in the subretinal space. Associated retinal reflectivity changes are related to lesion stages and are consistent with perturbations to photoreceptors, as suggested by histology

    Observations of Toroidal Coupling for Low-N Alfven Modes in the Tca Tokamak

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    The antenna structure in the TCA tokamak is phased to excite preferentially Alfven waves with known toroidal and poloidal wave numbers. Surprisingly, the loading spectrum includes both discrete and continuum modes with poloidal wave numbers incompatible with the antenna phasing. These additional modes, which are important for our heating experiments, can be attributed to linear mode coupling induced by the toroidicity of the plasma column, when we take into account ion-cyclotron effects

    Robustness assessment of the ‘cooperation under resource pressure’ (CURP) model: Insights on resource availability and sharing practices among hunter-gatherers

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    A well-known challenge in archaeological research is the exploration of the social mechanisms that hunter-gatherers may have implemented throughout history to deal with changes in resource availability. The agent-based model (ABM) ‘cooperation under resource pressure’ (CURP) was conceived to explore food stress episodes in societies lacking a food preservation technology. It was particularly aimed at understanding how cooperative behaviours in the form of food sharing practices emerge, increase and may become the prevailing strategy in relation to changes in resource availability and expectancy of reciprocity. CURP’s main outcome is the identification of three regimes of behaviour depending on the stress level. In this work, the model’s robustness to the original selection mechanism (random tournament) is assessed, as different dynamics can lead to different persistent regimes. For that purpose, three other selection mechanisms are implemented and evaluated, to identify the prevailing states of the system. Results show that the three regimes are robust irrespective of the analysed dynamics. We consequently examine in more detail the long-term archaeological implications that these results may have.Spanish Ministry of Economy and Competitiveness (former Ministry of Science and Innovation): SimulPast Project (CSD2010- 00034 CONSOLIDER-INGENIO 2010), HAR2009-06996 and CULM Project (HAR2016- 77672-P); from the Argentine National Scientific and Technical Research Council (CONICET): Project PIP-0706; from the Wenner-Gren Foundation for Anthropological Research: Project GR7846; from the project H2020 FET OPEN RIA IBSEN/662725 and from the European Social Fund as one of the authors is the recipient of a predoctoral grant from the Department of Education of Junta de Castilla y León (Spain)

    Are psychosocial interventions effective in reducing alcohol consumption during pregnancy and motherhood?:A systematic review and meta‐analysis

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    Background and Aims Alcohol use by pregnant and parenting women can have serious and long-lasting consequences for both the mother and offspring. We reviewed the evidence for psychosocial interventions to reduce maternal drinking. Design Literature searches of PsycINFO, PubMed and Scopus identified randomised controlled trials of interventions with an aim of reduced drinking or abstinence in mothers or pregnant women. Setting Interventions were delivered in healthcare settings and homes. Participants Pregnant women and mothers with dependent children. Interventions Psychosocial interventions were compared with usual care or no intervention. Measurements The revised Cochrane risk-of-bias tool for randomised trials was used for quality assessments. Narrative synthesis summarised the findings of the studies with a subset of trials eligible for random-effects meta-analysis. General and alcohol-specific behaviour change techniques (BCTs) were identified to investigate potential mechanism of change. Results Twenty-four studies were included (20 pregnancy, four motherhood). Because of quality of reporting, data from only six pregnancy and four motherhood studies could be pooled. A significant treatment effect was revealed by the meta-analyses of pregnancy studies regarding abstinence (OR = 2.31, 95% CI = 1.61, 3.32; P < 0.001) and motherhood studies regarding a reduction in drinking (standardised mean difference [SMD] = −0.20, 95% CI = −0.38, −0.02; P = 0.03). Narrative synthesis of the remaining trials yielded inconsistent results regarding intervention effectiveness. A wide range of BCTs were used, present in both effective and ineffective interventions. The most commonly used general and alcohol-specific BCTs included information about consequences, social support, goal setting and action planning. Conclusions In pregnant women identified as consuming alcohol, psychosocial interventions appear to increase abstinence rates compared with usual care or no intervention. Similarly, such interventions appear to lead to a reduction in alcohol consumption in mothers with dependent children. It is unclear that behaviour change techniques are contributing to these effects. Conclusions from randomised controlled trials are only meaningful if the behavioural outcome, population, setting, intervention and comparator are clearly reported. An important barrier when it comes to identifying effective behaviour change techniques is a widespread failure to provide enough information in study reports

    A small-N cross-sectional study of British unions' environmental attitudes and activism - and the prospect of a green-led renewal

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    Unions understand the environmental agenda as a technocentric one but also believe it can function as a vehicle for renewal. It is developing slowly, with unions behaving cautiously—resources are scarce. Although popular with members, there is limited evidence that it is effective as a recruitment tool and whilst employers are willing to work in partnership with unions on it, this may confer only phony insider status. Overall, the agenda has limited appeal to the types of employees and employers unions must recruit in order to grow. Identifying a clear environmental premium for members may help
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