91 research outputs found
Environmental stresses mediate endophyte–grass interactions in a boreal archipelago
No full textSummary
1. Both evolutionary theory and empirical evidence from agricultural research support the view that asexual, vertically transmitted fungal endophytes are typically plant mutualists that develop high infection frequencies within host grass populations. In contrast, endophyte–grass interactions in natural ecosystems are more variable, spanning the range from mutualism to antagonism and comparatively little is known about their range of response to environmental stress.
2. We examined patterns in endophyte prevalence and endophyte–grass interactions across nutrient and grazing (from Greylag and Canada geese) gradients in 15 sites with different soil moisture levels in 13 island populations of the widespread grass Festuca rubra in a boreal archipelago in Sweden.
3. In the field, endophyte prevalence levels were generally low (range = 10–53%) compared with those reported from agricultural systems. Under mesic‐moist conditions endophyte prevalence was constantly low (mean prevalence = 15%) and was not affected by grazing pressure or nutrient availability. In contrast, under conditions of drought, endophyte prevalence increased from 10% to 53% with increasing nutrient availability and increasing grazing pressure.
4. In the field, we measured the production of flowering culms, as a proxy for host fitness, to determine how endophyte‐infected plants differed from uninfected plants. At dry sites, endophyte infection did not affect flowering culm production. In contrast, at mesic‐moist sites production of flowering culms in endophyte‐infected plants increased with the covarying effects of increasing nutrient availability and grazing pressure, indicating that the interaction switched from antagonistic to mutualistic.
5. A concurrent glasshouse experiment showed that in most situations, the host appears to incur some costs for harbouring endophytes. Uninfected grasses generally outperformed infected grasses (antagonistic interaction), while infected grasses outperformed uninfected grasses (mutualistic interaction) only in dry, nutrient‐rich conditions. Nutrient and water addition affected tiller production, leaf number and leaf length differently, suggesting that tillers responded with different strategies. This emphasizes that several response variables are needed to evaluate the interaction.
6. Synthesis. This study found complex patterns in endophyte prevalence that were not always correlated with culm production. These contrasting patterns suggest that the direction and strength of selection on infected plants is highly variable and depends upon a suite of interacting environmental variables that may fluctuate in the intensity of their impact, during the course of the host life cycle.Peer reviewedfinal article publishedantagonist–mutualist continuumwater stresssymbiosisSwedennutrient stressherbivorygrassFestuca rubraEpichloë festucaeendophyt
Towards Improving Knowledge Capitalization System for Sport Events Legacy
No full textInternational audienceKnowledge Management is a way to answer the problem of capitalizing on the companies’ knowledge. Knowing that hosting sports events (SE) requires organizers to learn from past events to not repeat mistakes, we examine knowledge management in a sport events legacy (SEL). Thus, in this paper, we propose in first, two conceptual models based on UML; one for the SE, another for SEL. Secondly, we propose a system to manage SEL to assist in the process of data acquisition and capitalization on SE knowledge. This system helps to create an open collaborative platform for consultation, visualization of the spinoffs of sport events. It is intended to be used by public policies, territories, journalists, citizens, historians and all others. We propose also to take into account the spatiotemporal aspects of SE
Towards Culture-Aware Smart and Sustainable Cities: Integrating Historical Sources in Spatial Information Infrastructures
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One Step Forward and Two Steps Back: The Role of Civil Society Organizations in Reversed Integration Processes among Refugees in Norway
Get PDFThis is an open-access article distributed under the terms of the Creative Commons NonCommercial-NoDerivatives Attribution 4.0 International License (CC-BY-NC-ND 4.0), which permits unrestricted distribution, and reproduction in any medium, provided the original author and source are credited, the material is not used for commercial purposes and is not altered in any way. See https:// creativecommons.org/ licenses/by-nc-nd/4.0/Refugees settling in Norway experience several barriers to labour market integration, such as language insufficiency, low or unrecognised formal competence, and discrimination. While numerous scholars have dealt with the issues of both policy implementation and the outcome of public measures, there is a growing interest in the contributions of civil society organizations (CSOs) to the labour market integration of refugees. Such an interest is fueled by the proliferation of neoliberal reforms in European welfare states and restrictive budgets, leading to increased recognition of CSOs as resolutions to social issues. Based on ethnographic fieldwork among refugees and employees in two CSOs in Norway, the findings suggest a particularly vulnerable phase immediately after the public introduction programme for refugees not moving on to employment, education, or training. Drawing on Bourdieu’s concept of different forms of capital in addition to Granovetter’s theory of social network, I argue that CSOs have a profound role in preventing the reversed integration processes that occur in this specific phase of settlement.publishedVersio
Group differences in word use and meaning: A text analysis of the abstract word, "Values"
No full textPeople often use the same word while meaning very different things. Text analysis procedures can be applied to determine something of the meaning of words, typically from a single author. Rarely, however, have these procedures been used to explore the differences between individuals with different backgrounds and agendas and yet who ostensibly claim to be talking about the same thing. In the current study, we explored the way in which an abstract word, ‘values’, was used by three interest groups in relation to the Wet Tropics World Heritage Area, in Australia. Documents about the Wet Tropics produced by three environmental organisations, involved in either research, management, or conservation activism, were compared for their use of the word 'values'. Using WordStat text processing software, distributional information in the localised sentence context (keyword frequencies by group and proximal co-occurrence) was explored for clues to differences in the applied meanings of 'values'. Type-token identities showed that vocabulary diversity was similar for all groups. Cluster analyses revealed group differences in word associations and conceptual themes surrounding ‘values’. The research group tended towards operational terms, in contrast with the management group themes relating to links with Indigenous landowners and their cultural ties to the land, and conservation group themes relating to economics and community development. As examples of language ‘slippage’, keywords associated with ‘values’ showed that presence of the expression can predict connotations of economic worth (ECONOMIC, VALUE, RESOURCE), positive and negative attributions (QUALITY, POTENTIAL, THREAT), and physical substance (FOREST, SPECIES, HABITAT). Values are additionally associated with environmentally relevant behaviours (CONTROL, PROTECTION, MANAGEMENT). It is essential for effective communication and credible environmental science that such core terms and considerations as environmental ‘values’ convey clear and shared meanings
On Fatigue Damage Assessment for Offshore Support Structures with Tubular Joints
Get PDFAbstractThe hot spot stress approach is commonly used for fatigue lifetime estimation of tubular joints. The standard approach consists of the linear superposition of stress components from axial, in-plane, and out of plane action, leading to 8 hot spot stresses equally divided along the circumference of each tubular joint. The fatigue lifetime for a joint is calculated by accumulating the fatigue damage over several load cases. The fatigue damage used per load case is commonly the maximum fatigue damage out of the 8 hot spots. In this study, another approach has been evaluated. Fatigue lifetime is estimated by accumulation of fatigue damage over load cases for each hot spot individually, instead of taking the maximum out of the 8 hot spots. The proposed approach is compared with the commonly used approach using a generic lattice type support structure for offshore wind turbines. In addition, the number of hot spots along the circumference of the joint is increased to 32 points in order to study the influence on the fatigue lifetime estimation. Results show a difference in the fatigue lifetime estimation for individual joints up to 26% when using the proposed approach for estimating the fatigue lifetime. Furthermore, it is shown that the consideration of 32 points along the circumference of tubular joints lead to more precise fatigue damage. Differences up to 11% were detected
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