109 research outputs found

    Lichens facilitate seedling recruitment in alpine heath

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    Abstract Questions How do mat thickness, physical structure and allelopathic properties of terricolous mat-forming lichens affect recruitment of vascular plants in dwarf-shrub and lichen heath vegetation?. Location The mountains of Dovrefjell, central Norway. Methods In autumn, seeds of ten vascular plant species were collected and sown in a common garden experiment with mats of six lichen species and bare-soil controls as experimental treatments. We recorded growing season soil temperature and moisture, and seedling recruitment and growth after one year. The effect of lichen secondary compounds on germination was tested in a growth chamber experiment and compared to the lichen-plant interactions detected under field conditions. Results The lichen mats buffered extreme soil temperatures and soil drying in dry weather, with soils below the thickest mats (Cladonia stellaris and C. rangiferina) experiencing the lowest temperature fluctuations. Seedling recruitment and seedling growth in the field and seed germination in the lab were species-specific. Seedling recruitment rates were overall higher within lichen mats than on bare soil, but the c. 6.5 cm thick mats of C. stellaris reduced recruitment of many species. The lab experiment suggested no overall strong effect of lichen allelopathy on seed germination, and effects on seed germination were only moderately correlated with the lichen-plant interactions observed for seedling recruitment in the field. Conclusions In harsh environments like alpine dwarf-shrub and lichen heaths, the presence of lichens and the resulting amelioration of the microclimate seems more important for vascular plant recruitment than are allelopathic effects often reported in lab experiments. We might therefore expect most terricolous lichens, depending on the plant species in focus, to facilitate rather than hamper the early stages of plant recruitment into lichen-dominated arctic-alpine heath vegetation. This article is protected by copyright. All rights reserved.Peer reviewe

    Species trait selection along a prescribed fire chronosequence

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    1. Fire is a widespread management practice used in the maintenance of European heathland. Frequent prescribed burns in small patches have been shown to benefit carabid communities; however, how fire favours specific life-history traits is poorly understood. 2. In this study, we identify characteristic species of the successional stages within heathlands, and find the traits which are characteristic of species in burnt areas versus areas dominated by older heath stands. 3. We identify 10 species as indicator species for heathland in the pioneer stage (0–5 years old); Amara lunicollis, Bembidion lampros, Calathus fuscipes, Carabus problematicus, Cicindela campestris, Nebria salina, Notiophilus aquaticus, Poecilus cupreus, P. lepidus and P. versicolor. Dyschirius globosus is identified as an indicator for the building stage (6–14 years old), and Carabus violaceus as an indicator for the mature stage (15–25 years old). 4. Moisture preference and diet are identified as traits that determine species response to prescribed fire. Collembolan specialists and species with no moisture preference are shown to be most abundant in burnt patches, whereas generalist predators and species with a high moisture preference are less tolerant of fire. 5. Knowledge of species sorting along a prescribed fire gradient can provide valuable information for heathland conservation.publishedVersio

    Reliability of an injury scoring system for horses

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    <p>Abstract</p> <p>Background</p> <p>The risk of injuries is of major concern when keeping horses in groups and there is a need for a system to record external injuries in a standardised and simple way. The objective of this study, therefore, was to develop and validate a system for injury recording in horses and to test its reliability and feasibility under field conditions.</p> <p>Methods</p> <p>Injuries were classified into five categories according to severity. The scoring system was tested for intra- and inter-observer agreement as well as agreement with a 'golden standard' (diagnosis established by a veterinarian). The scoring was done by 43 agricultural students who classified 40 photographs presented to them twice in a random order, 10 days apart. Attribute agreement analysis was performed using Kendall's coefficient of concordance (Kendall's <it>W</it>), Kendall's correlation coefficient (Kendall's τ) and Fleiss' kappa. The system was also tested on a sample of 100 horses kept in groups where injury location was recorded as well.</p> <p>Results</p> <p>Intra-observer agreement showed Kendall's <it>W </it>ranging from 0.94 to 0.99 and 86% of observers had kappa values above 0.66 (substantial agreement). Inter-observer agreement had an overall Kendall's <it>W </it>of 0.91 and the mean kappa value was 0.59 (moderate). Agreement for all observers versus the 'golden standard' had Kendall's τ of 0.88 and the mean kappa value was 0.66 (substantial). The system was easy to use for trained persons under field conditions. Injuries of the more serious categories were not found in the field trial.</p> <p>Conclusion</p> <p>The proposed injury scoring system is easy to learn and use also for people without a veterinary education, it shows high reliability, and it is clinically useful. The injury scoring system could be a valuable tool in future clinical and epidemiological studies.</p

    Slow recovery of High Arctic heath communities from nitrogen enrichment

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    Acknowledgements We are indebted to Ian Alexander who initiated the fertilisation experiment with SJW; to successive researchers involved in the experiment, John Baddeley, Nanette Madan, Lars Hogbom, Bernard Moyersen, Carmen Gordon; and to field assistants, Alison Horsburgh, Andrew Coughlan, Jo Wynn, Lora Crabtree. We thank Hans Kruijer and Michael Stech for assistance with bryophyte species identification in 2011. Funding for the initial experiment was provided by the NERC Arctic Terrestrial Ecology Special Topic Programme (GR3/9424, GR9/3433) with additional support from the CEC TMR Programme, Ny-Ålesund LSF and the British Ecological Society. This recovery study was funded by NERC (NE/I016899/1). The research was made possible by use of NERC facilities at Harland Huset; special thanks to Nick Cox and colleagues for their unfailing hospitality and support.Peer reviewedPostprintPostprin

    Implementing smartphone enabled collaborative travel: Routes to success in the tourism domain.

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    Smartphone technology can help identify current and anticipate future patterns of behaviour and, with its social networking capabilities, allow users to imagine and organise collaborative travel opportunities, such as lift share. This has led to the development of collaborative apps designed to enable activities like lift sharing. Such apps require new norms of behaviour to establish a user base and research has yet to address the socio-cultural barriers to both the use of this technology to organise travel and the sharing of personal space that collaborative travel entails. This paper reports the findings of a study which designed, built and tested a collaborative travel app in the tourism domain. Data derived from exploratory interviews, post-trial interviews and a questionnaire reveal that user age and extent of mobile engagement play a less significant role than expected, while other aspects of the social exchange, notably social tie strength, trust and obligations play a more marked role. A conceptual framework and discussion of strategies to address these barriers provides insight into appropriate contexts and routes for implementation of collaborative travel apps

    Effect of tapered versus stable treatment with tumour necrosis factor inhibitors on disease flares in patients with rheumatoid arthritis in remission: a randomised, open label, non-inferiority trial

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    Objectives Many patients with rheumatoid arthritis (RA) require treatment with tumour necrosis factor inhibitor (TNFi) to reach remission. It is debated whether tapering of TNFi to discontinuation should be considered in sustained remission. The aim of ARCTIC REWIND TNFi was to assess the effect of tapering TNFi to withdrawal compared with stable treatment on the risk of disease activity flares in patients with RA in remission ≥1 year.Methods This randomised, open-label, non-inferiority trial was undertaken at nine Norwegian rheumatology departments. Patients with RA in remission ≥12 months on stable TNFi therapy were allocated by computer-based block-randomisation to tapering to discontinuation of TNFi or stable TNFi. Conventional synthetic disease-modifying antirheumatic co-medication was unchanged. The primary endpoint was disease flare during the 12-month study period (non-inferiority margin 20%), assessed in the per-protocol population.Results Between June 2013 and January 2019, 99 patients were enrolled and 92 received the allocated treatment strategy. Eighty-four patients were included in the per-protocol population. In the tapering TNFi group, 27/43 (63%) experienced a flare during 12 months, compared with 2/41 (5%) in the stable TNFi group; risk difference (95% CI) 58% (42% to 74%). The tapering strategy was not non-inferior to continued stable treatment. The number of total/serious adverse events was 49/3 in the tapering group, 57/2 in the stable group.Conclusion In patients with RA in remission for more than 1 year while using TNFi, an increase in flare rate was reported in those who tapered TNFi to discontinuation. However, most regained remission after reinstatement of full-dose treatment.Pathophysiology and treatment of rheumatic disease

    Effect of half-dose vs stable-dose conventional synthetic disease-modifying antirheumatic drugs on disease flares in patients with rheumatoid arthritis in remission: the ARCTIC REWIND randomized clinical trial

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    This randomized trial compares the effects of half-dose conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) vs stable-dose csDMARDs on the risk of flares in patients with rheumatoid arthritis in sustained remission.Importance Sustained remission has become an achievable goal for patients with rheumatoid arthritis (RA) receiving conventional synthetic disease-modifying antirheumatic drugs (csDMARDs), but how to best treat patients in clinical remission remains unclear. Objective To assess the effect of tapering of csDMARDs, compared with continuing csDMARDs without tapering, on the risk of flares in patients with RA in sustained remission. Design, Setting, and Participants ARCTIC REWIND was a multicenter, randomized, parallel, open-label noninferiority study conducted in 10 Norwegian hospital-based rheumatology practices. A total of 160 patients with RA in remission for 12 months who were receiving stable csDMARD therapy were enrolled between June 2013 and June 2018, and the final visit occurred in June 2019. Interventions Patients were randomly assigned to half-dose csDMARDs (n = 80) or stable-dose csDMARDs (n = 80). Main Outcomes and Measures The primary end point was the proportion of patients with a disease flare between baseline and the 12-month follow-up, defined as a combination of Disease Activity Score (DAS) greater than 1.6 (threshold for RA remission), an increase in DAS score of 0.6 units or more, and at least 2 swollen joints. A disease flare could also be recorded if both the patient and investigator agreed that a clinically significant flare had occurred. A risk difference of 20% was defined as the noninferiority margin. Results Of 160 enrolled patients (mean [SD] age, 55.1 [11.9] years; 66% female), 156 received the allocated therapy, of which 155 without any major protocol violations were included in the primary analysis population (77 receiving half-dose and 78 receiving stable-dose csDMARDs). Flare occurred in 19 patients (25%) in the half-dose csDMARD group compared with 5 (6%) in the stable-dose csDMARD group (risk difference, 18% [95% CI, 7%-29%]). Adverse events occurred in 34 patients (44%) in the half-dose group and 42 (54%) in the stable-dose group, none leading to study discontinuation. No deaths occurred. Conclusions and Relevance Among patients with RA in remission taking csDMARD therapy, treatment with half-dose vs stable-dose csDMARDs did not demonstrate noninferiority for the percentage of patients with disease flares over 12 months, and there were significantly fewer flares in the stable-dose group. These findings do not support treatment with half-dose therapy.Question In patients with rheumatoid arthritis in remission taking conventional synthetic disease-modifying antirheumatic drugs (csDMARDs), is reducing the csDMARDs to half dose noninferior to stable csDMARD dosage for the outcome of rheumatoid arthritis flares? Findings In this randomized clinical trial that included 160 patients with rheumatoid arthritis in remission taking csDMARD therapy, treatment with half-dose vs stable-dose csDMARDs resulted in disease flares in 25% vs 6% over 12 months; this did not meet the noninferiority criterion of a 20% difference. There were significantly fewer patients with flares in the stable-dose group. Meaning These findings do not support the use of half-dose treatment in patients with rheumatoid arthritis in remission taking csDMARDs.Pathophysiology and treatment of rheumatic disease
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