467 research outputs found

    A modification of the leaf-nets method for sampling benthic invertebrates in spring habitats

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    The full ecological potential of spring habitats remains relatively unexplored mostly because of the lack of standardized sampling procedures and difficulties to collect representative biological samples, especially in small-sized springs. Recent studies on sampling methodologies in spring habitats indicated that a modified Surber net with a reduced frame area, reliably describes the structure and composition of spring communities. This method, however, is very invasive and may severely impact the spring, especially when a large number of samples is required. The paper presents a new quantitative method (leaf-nets) for sampling crenic invertebrates which combines a rather high efficiency with negligible impacts on spring habitat structure and biota. The effectiveness of the new methodology was tested in a medium-size rheocrene spring in Central Apennine, where spring assemblages were sampled in parallel with a modified Surber net and with the new method. Taxa richness and density were higher in the Surber net, while no between-method differences were recorded for the number of insect taxa and Simpson diversity. Furthermore, the overall functional organization of Surber net and leaf-nets assemblages was very similar. The new method sampled only 25% of the individuals cumulatively collected, but 75% of the total richness, with a good representation of the structure and the functional organization of spring assemblages. In comparison with the Surber net, the negligible loss of information of the new method is highly compensated by its minor invasivity, lower impacts on spring microhabitats and invertebrate populations and by its higher versatility. Leaf-nets could also be used to assess leaf-detritus breakdown in springs, thus allowing a better ecological characterization of these ecosystems. </p

    Observational evidence of intensified nocturnal urban heat island during heatwaves in European cities

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    A heatwave (HW) is a large-scale meteorological event characterised by persistent and extremely high-temperature condition. At the local scale, the urban heat island (UHI) is another thermal-related phenomenon defined as an urban area warmer than its surrounding regions due to different surfaces’ capabilities to absorb and store heat. However, the assessment about the effect produced on UHI by HW events is not homogeneous. Indeed, regarding the capability of HWs to influence the urban-rural temperature difference, several studies report different conclusions describing both an exacerbation and a reduction of UHI during HW events. In this context, the present study analyses in situ long records of temperature measurements (20 years) to provide observational shreds of evidence of UHI modification under HW conditions. We examine data from the European Climate Assessment &amp; Dataset and World Meteorological Organization computing the UHI index (UHII) to quantify the UHI effect intensity in 37 European cities during the last 20 summers. The results show an UHII intensification for 28 of the 32 cities affected by positive UHI during extremely high temperatures at night, while substantial variations are not observed during the daytime. The time evolution of UHI during a HW highlights that a more significant and persistent urban-rural temperature gradient explains the UHI intensification. Finally, the relationship between the large and local-scale temperature phenomena reveals that continental high-temperature periods are often associated with prominent temperature differences between small-scale urban and rural environments, assessing the impact of large-scale features on thermal stress at the local scale

    Stigmatisation and resilience in inflammatory bowel disease

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    © 2019, The Author(s). Inflammatory bowel disease, which includes Crohn’s disease and ulcerative colitis, is an immune-mediated, chronic relapsing disorder characterised by severe gastrointestinal symptoms that dramatically impair patients’ quality of life, affecting psychological, physical, sexual, and social functions. As a consequence, patients suffering from this condition may perceive social stigmatisation, which is the identification of negative attributes that distinguish a person as different and worthy of separation from the group. Stigmatisation has been widely studied in different chronic conditions, especially in mental illnesses and HIV-infected patients. There is a growing interest also for patients with inflammatory bowel disease, in which the possibility of disease flare and surgery-related issues seem to be the most important factors determining stigmatisation. Conversely, resilience represents the quality that allows one to adopt a positive attitude and good adjustments despite adverse life events. Likewise, resilience has been studied in different populations, age groups, and chronic conditions, especially mental illnesses and cancer, but little is known about this issue in patients with inflammatory bowel disease, even if this could be an interesting area of research. Resilience can be strengthened through dedicated interventions that could potentially improve the ability to cope with the disease. In this paper, we focus on the current knowledge of stigmatisation and resilience in patients with inflammatory bowel disease

    Assessment of river quality within the context of the EU's water framework directive (2000/60/EC): the RiverNet Experiences

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    EnThe purpose of the EU's Water Framework Directive (WFD)is the achievement of ecological good status for all its superficial water bodies and courses.However,the most controversial and difficult aspect is the choice of an appropriate method to define a “reference condition ”,the expected value upon which comparisons are to be made and quantitatively expressed as EQR metric (ecological quality ratio).A major burden is the adjustment of national standards to assess the quality of aquatic habitats according to the technical specifications explicitly stated in the WFD.This aspect is also one of the major objectives within the RiverNet project.We compared standard methods used in Italy (not compliant with WFD requirements)with those currently under study by the pan-European intercalibration panel.Data spanning one year (2002)from the Abruzzo monitoring programwere used.Data from 229 samples (78 sites and 38 water courses)were reanalyzed using both Italian (LIM,IBE,SECA)and other metrics (family richness,BMWP,ASPT,EPT,EPT%).Resulting ecological status assessments were compared quantitatively and expressed as EQR.Indices based on benthic invertebrates were closely interrelated ($R2==0.71 –0.88 for pairwise correlations),and performed better than the abiotic LIM index.The BMWP index seems better suited than the non-WFD-compliant IBE index to describe ecological status.Though the dataset was relatively limited,we were able to identify 13 class-1 (least impacted)sites that can be used as reference sites for Abruzzo.Additionally,EQR-based range and threshold values for each tested metric were quantified for the high, good and moderate quality lasses.Utilization of historical data may be a cost-and time-effective approach potentially leading to a regional and nationwide establishment of reference conditions and range quality-class values for riverine systems

    A modification of the leaf-bags method to assess spring ecosystem functioning: benthic invertebrates and leaf-litter breakdown in Vera Spring (Central Italy)

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    The evaluation of leaf detritus processing (decomposition and breakdown) is one of the most simple and cost-effective method to assess the functional characteristics of freshwater ecosystems. However, in comparison with other freshwater habitats, information on leaf litter breakdown in spring ecosystems is still scarce and fragmentary. In this paper, we present results of the first application of a variant of the leaf-bags method to assess structure of macroinvertebrate assemblages and leaf-litter breakdown in a Central Apennines (Italy) cold spring which was investigated from July 2016 to October 2016. Notwithstanding the stable conditions of almost all hydrological and physico-chemical parameters, we found significant temporal differences in (i) % of mass loss of poplar leaves (ii) number of Ephemeroptera, Plecoptera and Trichoptera taxa, (iii) shredder and predator densities. We demonstrate that detritus processing in cold springs may be faster than or as fast as in warmer streams/rivers. Shredders activity and biocoenotic interactions, rather than temperature and nutrients load, were the main drivers of the process. A routine application of the modified leaf-bags may contribute to expand our knowledge on detritus processing in cold springs and may help to predict impacts of climate warming on freshwater ecosystem functioning

    Graphene field effect transistors with Niobium contacts and asymmetric transfer characteristics

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    We fabricate back-gated field effect transistors using Niobium electrodes on mechanically exfoliated monolayer graphene and perform electrical characterization in the pressure range from atmospheric down to 10-4 mbar. We study the effect of room temperature vacuum degassing and report asymmetric transfer characteristics with a resistance plateau in the n-branch. We show that weakly chemisorbed Nb acts as p-dopant on graphene and explain the transistor characteristics by Nb/graphene interaction with unpinned Fermi level at the interface.Comment: 10 pages, Research Pape

    Abnormal thymic stromal lymphopoietin expression in the duodenal mucosa of patients with coeliac disease

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    OBJECTIVE: The short isoform of thymic stromal lymphopoietin (TSLP), a cytokine constitutively expressed by epithelial cells, is crucial in preserving immune tolerance in the gut. TSLP deficiency has been implicated in sustaining intestinal damage in Crohn's disease. We explored mucosal TSLP expression and function in refractory and uncomplicated coeliac disease (CD), a T-cell-mediated enteropathy induced by gluten in genetically susceptible individuals. DESIGN: TSLP isoforms-long and short-and receptors-TSLPR and interleukin (IL)-7Rα-were assessed by immunofluorescence, immunoblotting and qRT-PCR in the duodenum of untreated, treated, potential and refractory patients with CD. The ability of the serine protease furin or CD biopsy supernatants to cleave TSLP was evaluated by immunoblotting. The production of interferon (IFN)-γ and IL-8 by untreated CD biopsies cultured ex vivo with TSLP isoforms was also assessed. RESULTS: Mucosal TSLP, but not TSLPR and IL-7Rα, was reduced in untreated CD and refractory CD in comparison to treated CD, potential CD and controls. Transcripts of both TSLP isoforms were decreased in active CD mucosa. Furin, which was overexpressed in active CD biopsies, was able to cleave TSLP in vitro. Accordingly, refractory and untreated CD supernatants showed higher TSLP-degrading capacity in comparison to treated CD and control supernatants. In our ex vivo model, both TSLP isoforms significantly downregulated IFN-γ and IL-8 production by untreated CD biopsies. CONCLUSIONS: Reduced mucosal TSLP expression may contribute to intestinal damage in refractory and untreated CD. Further studies are needed to verify whether restoring TSLP might be therapeutically useful especially in refractory patients with CD

    Report on first inflight data of bepicolombo’s mercury orbiter radio-science experiment

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    BepiColombo’s Mercury Orbiter Radio-science Experiment (MORE) was conceived to enable extremely accurate radio tracking measurements of the Mercury Planetary Orbiter to precisely determine the gravity field and rotational state of Mercury, and to test theories of gravitation (e. g. Einstein’s Theory of General Relativity). The design accuracy of the radio tracking data was 0.004 mm/sec (at 1000 s integration time) for range-rate measurements and 20 cm for range (at a few seconds of integration time). These accuracies are attained due to a combination of simultaneous two-way microwave links at X (7.2-8.4 GHz) and Kaband (32-34 GHz) to calibrate the dispersive plasma noise component. In this letter, we present the first analysis of range and range-rate data collected by ESA’s deep space antenna (DSA) during the initial cruise phase of BepiColombo. The novel 24 Mcps pseudo-noise (PN) modulation of the Ka-band carrier, enabled by MORE’s Ka-band Transponder (KaT), built by Thales Alenia Space Italy, provided two-way range measurements to centimeterlevel accuracy, with an integration time of 4.2 s at 0.29 astronomical units. In tracking passes with favorable weather conditions, range-rate measurements attained an average accuracy of 0.01 mm/s at 60 s integration time. Data from 20 to 24 May 2019 were combined in a multi-pass analysis to test the link stability on a longer timescale. The results confirm the noise level observed with the single-pass analysis and provide a preliminary indication that the MORE PN ranging system at 24 Mcps is compatible with the realization of an absolute measurement, where the need to introduce range biases in the orbital fit is much more limited than in the past. We show that in the initial cruise test the BepiColombo radio link provided range measurements of unprecedented accuracy for a planetary mission, and that, in general, all target accuracies for radio-metric measurements were exceeded
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