146 research outputs found

    Facilitation of a tropical seagrass by a chemosymbiotic bivalve increases with environmental stress

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    Facilitation of foundation species is critical to the structure, function and persistence of ecosystems. Understanding the dependence of the strength of this facilitation on environmental conditions is important for informed ecosystem management and for predicting the impacts of global change. In coastal seagrass habitats, chemosymbiotic lucinid bivalves can facilitate seagrasses by decreasing potentially toxic levels of sulphide in sediment porewater. However, variation in the strength of lucinid–seagrass facilitation with environmental context has not been experimentally investigated. We tested the hypothesis that the presence of the tiger lucine Codakia orbicularis becomes more important to the growth and survival of the seagrass Thalassia testudinum under decreased light availability and increased sulphide stress. In a mesocosm experiment, we reduced average ambient-light to T. testudinum by 64% and/or increased sediment porewater sulphide concentrations by ~200% and compared growth and tissue chemistry of T. testudinum with and without C. orbicularis. We found that T. testudinum was better able to maintain growth under shading and sulphide stress when C. orbicularis was present. C. orbicularis strongly decreased sediment porewater sulphide, an effect that minimized sulphur build-up in seagrass tissue and was likely achieved through bioirrigation as well as chemoautotrophy. The relative effects of C. orbicularis on T. testudinum growth were strongest in the presence of environmental stressors. Synthesis. The strength of lucinid–seagrass facilitation increases under environmental conditions that hinder the ability of seagrass to detoxify sulphide. Our results provide evidence of a potential mechanism by which the spatiotemporal association between lucinids and seagrasses is maintained and support the incorporation of interspecific facilitation into conservation and restoration strategies for foundation species in the face of increasing anthropogenic impact and global change

    De cultuursector is als een alp, hoe hoger je komt hoe witter het wordt

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    Het thema culturele diversiteit in de culturele sector staat hoog op de politieke agenda van Rotterdam. Ondanks het tot dusver gevoerde beleid is de cultuursector nog geen afspiegeling van de Rotterdamse samenleving. De Rotterdamse Raad voor Kunst e

    Guidelines of the International Headache Society for Controlled Clinical Trials in Cluster Headache

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    In 1995, a committee of the International Headache Society developed and published the first edition of the Guidelines for Controlled Trials of Drugs in Cluster Headache. These have not been revised. With the emergence of new medications, neuromodulation devices and trial designs, an updated version of the International Headache Society Guidelines for Controlled Clinical Trials in Cluster Headache is warranted. Given the scarcity of evidence-based data for cluster headache therapies, the update is largely consensus-based, but takes into account lessons learned from recent trials and demands by patients. It is intended to apply to both drug and neuromodulation treatments, with specific proposals for the latter when needed. The primary objective is to propose a template for designing high quality, state-of-the-art, controlled clinical trials of acute and preventive treatments in episodic and chronic cluster headache. The recommendations should not be regarded as dogma and alternative solutions to particular methodological problems should be explored in the future and scientifically validated

    PAX3-FOXO1 uses its activation domain to recruit CBP/P300 and shape RNA Pol2 cluster distribution

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    Activation of oncogenic gene expression from long-range enhancers is initiated by the assembly of DNA-binding transcription factors (TF), leading to recruitment of co-activators such as CBP/p300 to modify the local genomic context and facilitate RNA-Polymerase 2 (Pol2) binding. Yet, most TF-to-coactivator recruitment relationships remain unmapped. Here, studying the oncogenic fusion TF PAX3-FOXO1 (P3F) from alveolar rhabdomyosarcoma (aRMS), we show that a single cysteine in the activation domain (AD) of P3F is important for a small alpha helical coil that recruits CBP/p300 to chromatin. P3F driven transcription requires both this single cysteine and CBP/p300. Mutants of the cysteine reduce aRMS cell proliferation and induce cellular differentiation. Furthermore, we discover a profound dependence on CBP/p300 for clustering of Pol2 loops that connect P3F to its target genes. In the absence of CBP/p300, Pol2 long range enhancer loops collapse, Pol2 accumulates in CpG islands and fails to exit the gene body. These results reveal a potential novel axis for therapeutic interference with P3F in aRMS and clarify the molecular relationship of P3F and CBP/p300 in sustaining active Pol2 clusters essential for oncogenic transcription

    Under positive pressure: how stakeholder pressure affects corporate social responsibility implementation

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    This study tests a model that links stakeholder pressure to the implementation of corporate social responsibility (CSR) activities and market performance. Stakeholder groups and competitors might exert pressure on companies to implement CSR, which could lead to positive effects on market performance. Using structural equation modeling (SEM), the authors find that stakeholders and competitors exert pressure differently. The effect of CSR implementation on market performance is moderated by market dynamism: It affects market performance more in dynamic environments. The authors discuss implications for both companies and stakeholders

    Eliciting the Demand for Long Term Care Coverage: A Discrete Choice Modelling Analysis

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    We evaluate the demand for long term care (LTC) insurance prospects in a stated preference context, by means of the results of a choice experiment carried out on a representative sample of the Emilia-Romagna population. Choice modelling techniques have not been used yet for studying the demand for LTC services. In this paper these methods are first of all used in order to assess the relative importance of the characteristics which define some hypothetical insurance programmes and to elicit the willingness to pay for some LTC coverage prospects. Moreover, thanks to the application of a nested logit specification with partial degeneracy, we are able to model the determinants of the preference for status quo situations where no systematic cover for LTC exists. On the basis of this empirical model, we test for the effects of a series of socio-demographic variables as well as personal and household health state indicators
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