7,669 research outputs found
Malignant and noninvasive skin tumours in renal transplant recipients.
Background. Transplant recipients require immunosuppression to prevent graft rejection. This conveys an increased risk of malignancy, particularly skin tumours. There is a need for up-to-date data for the South of England. Method. Pathology records were reviewed for 709 kidney transplant recipients on immunosuppression at our hospital from 1995 to 2008. Skin tumours were recorded/analysed. Results. Mean age at transplant was 46 years. Mean length of follow-up was 7.2 years and total follow-up was 4926 person-years. 53 (7.5%) patients (39/458 (8.5%) males and 14/251 (5.6%) females) developed ≥1 skin malignancy. Cumulative incidences of 4.0%, 7.5%, and 12.2% were observed for those with <5, <10, and ≥10 years follow-up, respectively. The rate was 45 tumours per 1000 person-years at risk. Additionally, 21 patients (3.0%) only had noninvasive tumours. 221 malignant skin tumours were found: 50.2% were SCCs, 47.1% BCCs, and 2.7% malignant melanomas. Mean years to first tumour were 5.8. Mean number of tumours per patient was 4, with mean interval of 12 months. Conclusions. Despite changes in transplantation practice during the time since the last data were published in this region, these findings are similar to previous studies. This adds to the evidence allowing clinicians to inform patients in this region of their risk
Exceptional zeros and L-invariants of Bianchi modular forms
Let f be a Bianchi modular form, that is, an automorphic form for GL(2) over an imaginary quadratic field F. In this paper, we prove an exceptional zero conjecture in the case where f is new at a prime above p. More precisely, for each prime p of F above p we prove the existence of an L-invariant Lp, depending only on p and f, such that when the p-adic L-function of f has an exceptional zero at p, its derivative can be related to the classical L-value multiplied by Lp. The proof uses cohomological methods of Darmon and Orton, who proved similar results for GL(2) over the rationals. When p is not split and f is the base-change of a classical modular form F, we relate Lp to the L-invariant of F, resolving a conjecture of Trifkovi\'{c} in this case
Spatiotemporal variation of Diptera changes how we evaluate High Nature Value (HNV) wet grasslands
Proposed strategies to protect biodiversity within agricultural systems are often based on botanical criteria with plant species richness generally considered the prime indicator of conservation potential. While wet grasslands dominated by rushes (Juncus spp.) are commonly considered to be of lesser ecological value than those which are more botanically diverse (e.g. Carex dominated wet grasslands), their value for invertebrates such as Diptera has not yet been fully explored. Data from two Diptera families (Sciomyzidae and Syrphidae) were examined at spatial, temporal and spatiotemporal scales to determine the contribution of two different (Juncus and Carex dominated) wet grassland habitats towards the maintenance of Diptera diversity. The two habitats were significantly different in terms of community structure for both families and temporal variation was a significant component of dipteran diversity. Spatiotemporal analysis showed that species turnover between habitats at different times made the most significant contribution to overall Diptera diversity. Temporal variation of both families suggests that the relative importance of each habitat type to overall diversity fluctuates depending on sampling period, with both habitats supporting diversity at different times. Our results indicate that lowland wet grasslands characterised by Juncus cover need to be recognised as ecologically important for the maintenance of dipteran diversity. We discuss the possible implications for the diversity of Diptera in wet grasslands if these commonly perceived marginal areas (both agriculturally and ecologically) are ignored in conservation strategies. The necessity of recognising spatiotemporal variation when evaluating habitats using invertebrates as indicators is also discussed. © 2017 Springer Science+Business Media Dordrech
The diversity and composition of moth assemblages of protected and degraded raised bogs in Ireland
1. Peatlands are a globally important habitat, which act as net carbon stores. Raised bogs in the midlands of Ireland are a diminishing and increasingly fragmented peatland habitat as a result of drainage, peat extraction and agricultural intensification. A network of protected sites has been established, which is intended to represent the best abiotic and plant community systems.
2. Lepidoteran communities are an important component raised bog biodiversity and may be useful as biodiversity indicators, yet they are a neglected area of research. We address this by surveying nocturnal lepidopteran communities on six degraded and six protected raised bogs. We collected 1,816 individuals (representing 93 species) across all sites.
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3. Poisson generalised linear models were fitted to our count data and assessed using the Akaike information criterion (AIC) values. Models that included designation status were preferred for six species, three of which were more abundant on designated sites and three were more abundant on degraded sites. We discuss these findings in relation to the species’ known autecologies. Larval food plant choice, particularly due to the presence of invasive and non-typical plants, explained the alignment of species with undesignated sites. Other factors such as structural heterogeneity or nectar availability, may explain the alignment of most species with designated sites.
4. Rank abundance diagrams (RADs) of the total moth community were similar between protected and degraded sites, but the RADs of bog-associated species of conservation concern were different between protected and degraded sites with rarer bog associates being relatively better represented at the protected sites. This result was supported by Multi-response permutation-procedure (MRPP) analysis.
5. In general, differences between moth communities on degraded and protected raised bogs are rather subtle, with assemblages on both site types generally similar, but there is evidence that the “coarse filter” approach to conservation is working for some of the most important moth communities i.e. those that are bog-associated and of conservation concern. However, degraded sites may have a role to play in peatland invertebrate conservation, hitherto undervalued
Seasonal patterns of metals and nutrients in Phragmites australis (Cav.) Trin. ex Steudel in a constructed wetland in the west of Ireland
© 2017 Elsevier B.V. An understanding of the seasonal variation in the standing stock of metals and nutrients in emergent vegetation of constructed wetlands (CWs), as well as the amounts present in aboveground (AG) and belowground (BG) biomass, is crucial to their design and management. Given that biomass harvesting is a labour and time consuming operation, a paucity of information currently exists on accumulation and standing stocks in biomass in CWs, in particular in North Western European countries. To address this knowledge gap, this paper examined the seasonal variations of metals and nutrients in Phragmites australis (Cav.) Trin. ex Steudel in a CW treating municipal wastewater, with a view to identifying an optimal time for biomass harvesting of the AG vegetation. Although the AG biomass was greatest in August (1636 ± 507 g m −2 ), the maximum concentrations and accumulations of metals and nutrients occurred at different times throughout the duration of the study (April to November). Furthermore, with the exception of zinc and nitrogen, metals and nutrients measured in BG biomass ranged from 66% (phosphorus) to greater than 80% (nickel and chromium) of the AG biomass. This indicates that analysis of only the emergent shoots may significantly underestimate the metal and nutrient uptake and capacity of the plant. In order to effectively target the bulk of metals and nutrients, an AG harvest in late August or September is suggested
Indicators of Diptera diversity in wet grassland habitats are influenced by environmental variability, scale of observation, and habitat type
In low intensity agri-ecosystems such as wet grassland habitats, the inclusion of invertebrates in conservation assessments and monitoring is usually limited to charismatic groups such as bees or butterflies. However, wet grasslands support a wide range of inveterate groups, some of which may exhibit limited movement not generally represented by more mobile groups such as those typically examined. The use of surrogate species which exemplify broader invertebrate diversity has been suggested as a possible means of including these overlooked invertebrates (such as Diptera) in conservation planning within these habitats. Based on collections made by Malaise trap, we utilized two families of Diptera (Sciomyzidae and Syrphidae) as indicators of a wider range of dipteran diversity (nine Diptera families identified to parataxonomic unit level [PUs]) in wet grassland habitats. We examined the role of environmental variability, spatial scale, and habitat type on patterns of cross-taxon congruence for all three assemblages. Both environmental correlation and community congruence were significantly stronger among assemblages when examined at low spatial scales, highlighting the need to examine dipteran groups at scales untypical of current agri-environmental assessments; namely field and farm level. Furthermore, when wet grasslands were differentiated into two habitat categories (sedge and rush dominated grasslands), the significance of the community congruence increased markedly. This correlation was particularly strong between Sciomyzidae and PUs which demonstrated similar differentiation based on habitat type, implying that assemblages which exhibit comparable ecological partitioning are more likely to be useful surrogates of one another. Correlations between richness, abundance and Shannon's diversity were highly variable among groups, suggesting compositional analysis as the most appropriate examination of dipteran diversity for surrogacy studies. The results indicate that cross-assemblage congruence of Diptera is influenced by similarity of response to environmental variability, scale of observation, and examination of assemblages differentiated into appropriate habitat categories. The results illustrate the need to investigate invertebrate biodiversity surrogates at scales appropriate to the indicator groups and examine congruence among assemblages within specific habitat categories. Such an approach has the potential to maximise gamma diversity in areas where wet grasslands are under threat of intensification or abandonment. © 2017 Elsevier Lt
Identifying factors associated with the success and failure of terrestrial insect translocations
Translocation is increasingly used as a management strategy to mitigate the effects of human activity on biodiversity. Based on the current literature, we summarised trends in terrestrial insect translocations and identified factors associated with success and failure. As the authors’ definitions of success and failure varied according to the individual sets of goals and objectives in each project, we adopted a standardised species-specific definition of success. We applied generalised linear models and information-theoretic model selection to identify the most important factors associated with translocation success. We found literature documenting the translocation of 74 terrestrial insect species to 134 release sites. Of the translocations motivated by conservation, 52% were considered successful, 31% were considered to have failed and 17% were undetermined. Our results indicate that the number of individuals released at a translocation site was the most important factor associated with translocation success, despite this being a relatively infrequent perceived cause of failure as reported by authors. Factors relating to weather and climate and habitat quality were the most commonly perceived causes of translocation failure by authors. Consideration of these factors by managers during the planning process may increase the chance of success in future translocation attempts of terrestrial insects
On the Topologies of micro/macrohabitats in the Mollusca Sciomyzidae Taxocene
A new perspective on habitat is presented, which considers the topological relationships among macrohabitats of adults and the sub-set microhabitats of eggs and other juvenile stages. A model of seven topologies is presented using the snail-killing flies (Sciomyzidae: Diptera) as an exemplar; four of these topologies are drawn on a hydrological continuum from aquatic through shoreline to terrestrial, and three are presented as stand-alone specialized feeding groups. Colonisation-extinction dynamics are discussed in relation first to macrohabitat dynamics and then microhabitat structure. The topological perspective has wide application outside the Mollusca-Sciomyzidae taxocene e.g. in parasitoid wasp-host taxocenes, in phytophagous insect-host communities, for freshwater macro-invertebrates and even, in the context of a “landscape of fear”, for bird and mammal populations. The perspective taken is more “autecological” than the traditional “biotope” or resource view of habitats, yet is broad enough to encompass many different behavioural groups as shown for the Sciomyzidae
Stump-harvesting for bioenergy probably has transient impacts on abundance, richness and community structure of beetle assemblages
Harvesting of tree stumps for bioenergy is popular and, although the environmental impact has been considered with respect to ecosystem processes, there have been fewer studies on the impact of stump-harvesting on biodiversity. We carried out pitfall-trap surveys of beetle communities at eight plots across four sites (four plots were clear-fells where stumps remained and four were clear-fells where stumps were harvested). Initially, we recovered 7743 beetles when stumps were extracted but still on site (Year 1). All beetles were identified to family level and ground beetles and wood-associated beetles to species level. One year after stumps were extracted, the survey was repeated. In this collection, 2898 individual beetles were recovered. In Year 1, stump-harvesting had a negative impact on beetle abundance and richness. However, 1year after stumps were removed, there were no significant differences in these variables at any site. At the community level, stump-harvesting weakly but significantly, affected carabid composition. Oneyear after stumps were removed, stump-harvesting had no effect on community composition. Stump-harvesting initially negatively affects beetle abundance, family-richness and carabid species richness, as well as community structure, although any effects are not large, are site-specific and are probably not persistent. © 2017 The Royal Entomological Societ
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