88 research outputs found

    Interactions between diurnal winds and floodplain mosaics control the insect boundary layer in a river corridor

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    Insect flight along river corridors is a fundamental process that facilitates sustainable succession and diversity of aquatic and terrestrial insect communities in highly dynamic fluvial environments. This study examines variations in the thickness of the insect boundary layer (i.e., the pre-surface atmosphere layer in which air velocity does not exceed the sustained speed of flying insects) caused by interactions between diurnal winds and the heterogenous habitat mosaics in the floodplain of a braided river. Based on advective–diffusive theory, we develop and test a semi-empirical model that relates vertical flux of flying insects to vertical profiles of diurnal winds. Our model suggests that, in the logarithmic layer of wind, the density of insect fluxes decreases exponentially with the altitude due to the strong physical forcing. Inside the insect boundary layer, the insect fluxes can increase with the altitude while the winds speed remains nearly constant. We suggest a hypothesis that there is a close correspondence between the height of discontinuity points in the insect profiles (e.g. points with abrupt changes of the insect flux) and the displacement heights of the wind profiles (e.g. points above which the wind profile is logarithmic). Vertical profiles were sampled during three time-intervals at three different habitat locations in the river corridor: a bare gravel bar, a gravel bar with shrubs, and an island with trees and shrubs. Insects and wind speed were sampled and measured simultaneously over each location at 1.5-m intervals up to approximately 17 m elevation. The results support our working hypothesis on close correspondence between discontinuity and displacement points. The thickness of the insect boundary layer matches the height of the discontinuity points and was about 5 m above the bare gravel bar and the gravel bar with shrubs. Above the island, the structure of the insect boundary layer was more complex and consisted of two discontinuity points, one at the mean height of the trees’ crowns (ca. 15 m), and a second, internal boundary layer at the top of the shrubs (ca. 5 m). Our findings improve the understanding of how vegetation can influence longitudinal and lateral dispersal patterns of flying insects in river corridors and floodplain systems. It also highlights the importance of preserving terrestrial habitat diversity in river floodplains as an important driver of both biotic and abiotic (i.e., morphology and airscape) heterogeneit

    Interactions between diurnal winds and floodplain mosaics control the insect boundary layer in a river corridor

    Get PDF
    Insect flight along river corridors is a fundamental process that facilitates sustainable succession and diversity of aquatic and terrestrial insect communities in highly dynamic fluvial environments. This study examines variations in the thickness of the insect boundary layer (i.e., the pre-surface atmosphere layer in which air velocity does not exceed the sustained speed of flying insects) caused by interactions between diurnal winds and the heterogenous habitat mosaics in the floodplain of a braided river. Based on advective–diffusive theory, we develop and test a semi-empirical model that relates vertical flux of flying insects to vertical profiles of diurnal winds. Our model suggests that, in the logarithmic layer of wind, the density of insect fluxes decreases exponentially with the altitude due to the strong physical forcing. Inside the insect boundary layer, the insect fluxes can increase with the altitude while the winds speed remains nearly constant. We suggest a hypothesis that there is a close correspondence between the height of discontinuity points in the insect profiles (e.g. points with abrupt changes of the insect flux) and the displacement heights of the wind profiles (e.g. points above which the wind profile is logarithmic). Vertical profiles were sampled during three time-intervals at three different habitat locations in the river corridor: a bare gravel bar, a gravel bar with shrubs, and an island with trees and shrubs. Insects and wind speed were sampled and measured simultaneously over each location at 1.5-m intervals up to approximately 17 m elevation. The results support our working hypothesis on close correspondence between discontinuity and displacement points. The thickness of the insect boundary layer matches the height of the discontinuity points and was about 5 m above the bare gravel bar and the gravel bar with shrubs. Above the island, the structure of the insect boundary layer was more complex and consisted of two discontinuity points, one at the mean height of the trees’ crowns (ca. 15 m), and a second, internal boundary layer at the top of the shrubs (ca. 5 m). Our findings improve the understanding of how vegetation can influence longitudinal and lateral dispersal patterns of flying insects in river corridors and floodplain systems. It also highlights the importance of preserving terrestrial habitat diversity in river floodplains as an important driver of both biotic and abiotic (i.e., morphology and airscape) heterogeneity

    Influence of Surgical Technique on Post-Operative Complications in the Extraction of the Lower Third Molar: A Retrospective Study

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    The surgical extraction of the impacted third molar is frequently associated with several complications. The purpose of this study is to assess how two different surgical protocols affect post-operative complications during the extraction of the lower impacted third molars. In order to compare and evaluate two different techniques (triangular flap vs. envelope flap), and the relative post-extraction complications, two groups of 150 patients each underwent to surgical impacted third molar extraction and 60 days of follow-up. The complication rate in the two groups was 14.00% in group A and 17.33% in group B. There was a strong association between smoking (OR: 2.8) and the use of oral contraceptives (OR: 1.75) with complications. The age- and sex-related incidence of complications in hard tissue healing has great variability in the literature; the analysis performed on our data did not show a statistically significant association between them. Even though related to a higher incidence of transient changes in sensitivity, it was found that the envelope flap saw a lower percentage of complications. There is still no clarity on which is the best protocol for the extraction of the lower impacted third molar, and the choice often depends on the surgeon’s experience

    Benthic macroinvertebrate community shifts based on Bti-induced chironomid reduction also decrease Odonata emergence

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    Chironomid larvae (Diptera: Chironomidae) often dominate aquatic macroinvertebrate communities and are a key food source for many aquatic predators, such as dragonfly and damselfly larvae (Odonata). Changes in aquatic macroinvertebrate communities may propagate through terrestrial food webs via altered insect emergence. Bacillus thuringiensis israelensis (Bti)-based larvicides are widely used in mosquito control but can also reduce the abundance of non-biting chironomid larvae. We applied the maximum field rate of Bti used in mosquito control three times to six mesocosms in a replicated floodplain pond mesocosm (FPM) system in spring for two consecutive years, while the remaining six FPMs were untreated. Three weeks after the third Bti application in the first year, we recorded on average a 41% reduction of chironomid larvae in Bti-treated FPMs compared to untreated FPMs and a shift in benthic macroinvertebrate community composition driven by the reduced number of chironomid, Libellulidae and Coenagrionidae larvae (Odonata). Additionally, the number of emerging Libellulidae (estimated by sampling of exuviae in the second year) was reduced by 54% in Bti-treated FPMs. Since Odonata larvae are not directly susceptible to Bti, our results suggest indirect effects due to reduced prey availability (i.e., chironomid larvae) or increased intraguild predation. As Libellulidae include species of conservation concern, the necessity of Bti applications to their habitats, e.g. floodplains, should be carefully evaluated

    Eye fluke infection changes diet composition in juvenile European perch (Perca fluviatilis)

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    Intraspecific diet specialization, usually driven by resource availability, competition and predation, is common in natural populations. However, the role of parasites on diet specialization of their hosts has rarely been studied. Eye flukes can impair vision ability of their hosts and have been associated with alterations of fish feeding behavior. Here it was assessed whether European perch (Perca fluviatilis) alter their diet composition as a consequence of infection with eye flukes. Young-of-the-year (YOY) perch from temperate Lake MĂĽggelsee (Berlin, Germany) were sampled in two years, eye flukes counted and fish diet was evaluated using both stomach content and stable isotope analyses. Perch diet was dominated by zooplankton and benthic macroinvertebrates. Both methods indicated that with increasing eye fluke infection intensity fish had a more selective diet, feeding mainly on the benthic macroinvertebrate Dikerogammarus villosus, while less intensively infected fish appeared to be generalist feeders showing no preference for any particular prey type. Our results show that infection with eye flukes can indirectly affect interaction of the host with lower trophic levels by altering the diet composition and highlight the underestimated role of parasites in food web studies.Leibniz-AssociationPeer Reviewe

    Subsidy Quality Affects Common Riparian Web-Building Spiders: Consequences of Aquatic Contamination and Food Resource

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    Anthropogenic stressors can affect the emergence of aquatic insects. These insects link aquatic and adjacent terrestrial food webs, serving as high-quality subsidy to terrestrial consumers, such as spiders. While previous studies have demonstrated that changes in the emergence biomass and timing may propagate across ecosystem boundaries, the physiological consequences of altered subsidy quality for spiders are largely unknown. We used a model food chain to study the potential effects of subsidy quality: Tetragnatha spp. were exclusively fed with emergent Chironomus riparius cultured in the absence or presence of either copper (Cu), Bacillus thuringiensis var. israelensis (Bti), or a mixture of synthetic pesticides paired with two basal resources (Spirulina vs. TetraMin (R)) of differing quality in terms of fatty acid (FA) composition. Basal resources shaped the FA profile of chironomids, whereas their effect on the FA profile of spiders decreased, presumably due to the capacity of both chironomids and spiders to modify (dietary) FA. In contrast, aquatic contaminants had negligible effects on prey FA profiles but reduced the content of physiologically important polyunsaturated FAs, such as 20:4n-6 (arachidonic acid) and 20:5n-3 (eicosapentaenoic acid), in spiders by approximately 30% in Cu and Bti treatments. This may have contributed to the statistically significant decline (40%-50%) in spider growth. The observed effects in spiders are likely related to prey nutritional quality because biomass consumption by spiders was, because of our experimental design, constant. Analyses of additional parameters that describe the nutritional quality for consumers such as proteins, carbohydrates, and the retention of contaminants may shed further light on the underlying mechanisms. Our results highlight that aquatic contaminants can affect the physiology of riparian spiders, likely by altering subsidy quality, with potential implications for terrestrial food webs. (c) 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC

    Cloud distribution evaluated by the WRF model during the EUSO-SPB1 flight

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    EUSO-SPB1 was a balloon-borne mission of the JEM-EUSO (Joint Experiment Missions for Ex-treme Universe Space Observatory) Program aiming at the ultra-high energy cosmic ray (UHECR) observationsfrom space. We operated the EUSO-SPB1 telescope consisting of 1 m2Fresnel refractive optics and multi-anode photomultiplier tubes. With a total of 2304 channels, each performed the photon counting every 2.5 s,allowing for spatiotemporal imaging of the air shower events in an 11◦ 11◦field of view. EUSO-SPB1was the first balloon-borne fluorescence detector with a potential to detect air shower events initiated by theEeV energy cosmic rays. On 24 April 2017 UTC, EUSO-SPB1 was launched on the NASA’s Super PressureBalloon that flew at 16 – 33 km flight height for 12 days. Before the flight was terminated, 27 hours ofdata acquired in the air shower detection mode were transmitted to the ground. In the present work, we aim atevaluating the role of the clouds during the operation of EUSO-SPB1. We employ the WRF (Weather Researchand Forecasting) model to numerically simulate the cloud distribution below EUSO-SPB1. We discuss the keyresults of the WRF model and the impact of the clouds on the air shower measurement and the efficiency of thecosmic ray observation. The present work is a part of the collaborative effort to estimate the exposure for airshower detections

    Establishing a Large-Scale Field Experiment to Assess the Effects of Artificial Light at Night on Species and Food Webs

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    Artificial light at night (ALAN) is one of the most obvious hallmarks of human presence in an ecosystem. The rapidly increasing use of artificial light has fundamentally transformed nightscapes throughout most of the globe, although little is known about how ALAN impacts the biodiversity and food webs of illuminated ecosystems. We developed a large-scale experimental infrastructure to study the effects of ALAN on a light-naĂŻve, natural riparian (i.e., terrestrial-aquatic) ecosystem. Twelve street lights (20 m apart) arranged in three rows parallel to an agricultural drainage ditch were installed on each of two sites located in a grassland ecosystem in northern Germany. A range of biotic, abiotic, and photometric data are collected regularly to study the short- and long-term effects of ALAN on behavior, species interactions, physiology, and species composition of communities. Here we describe the infrastructure setup and data collection methods, and characterize the study area including photometric measurements. None of the measured parameters differed significantly between sites in the period before illumination. Results of one short-term experiment, carried out with one site illuminated and the other acting as a control, demonstrate the attraction of ALAN by the immense and immediate increase of insect catches at the lit street lights. The experimental setup provides a unique platform for carrying out interdisciplinary research on sustainable lighting

    Better Outcomes For Everybody (BOFE) evaluates the effectiveness and cost-effectiveness of a pharmacist-led intervention, delivered by community pharmacists in collaboration with physicians, in improving disease control, compared with usual care, in asthma and COPD patients during and after COVID-19: study protocol for a pragmatic, parallel randomised controlled trial

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    Introduction: In 2025, more than 400 million people will have asthma, and chronic obstructive pulmonary disease (COPD) will be the third leading cause of death by 2030. This trial, called better outcomes for everybody (BOFE), will evaluate the effectiveness and cost-effectiveness of a pharmacist-led intervention delivered by community pharmacists in collaboration with physicians to asthma and COPD patients to improve disease control compared with usual care. Methods: A pragmatic parallel 2-arm randomized controlled trial will be conducted in one Italian region (Sicily). A 2:1 randomization and sample size of 900 adult patients (450 with asthma, 450 with COPD) will be sufficient to detect a difference of 15% between the intervention and control groups using a dichotomized score (controlled versus non-controlled) of the Asthma Control Test (ACT) and the Clinical Chronic Obstructive Pulmonary Disease Questionnaire (CCQ) with a two tails, 99% power and 5% significance level. A hundred pharmacists will recruit 9 consecutive patients each and administer either ACT or CCQ according to the patients’ disease. Patients will be followed up for 12 months, and the pharmacists will meet their patients every three months. The control group will receive usual care, the intervention a bespoke, structured, and systematic consultation immediately after baseline and 6 months later. The primary outcomes are asthma and COPD control at baseline and 12 months. Secondary outcomes: risk of uncontrolled asthma and COPD, number of active ingredients, pharmaceutical care issues, adherence to medications, minimal clinically important differences in asthma and COPD, and a full health economic evaluation. The analysis will follow an intention-to-treat principle. Generalized estimating equations will be used to test the primary outcomes. Ethics approval was obtained. Discussion: This is the first study conducted in Italy to assess the effectiveness and cost�effectiveness of a pharmacist-led intervention in asthma and COPD patients at the same time. This research could introduce a new model of care that can be adapted to other chronic conditions in primary care settings. The results will be disseminated to service users and their families via media, healthcare professionals via professional training and meetings, and researchers via conferences and publications

    Dietary changes in predators and scavengers in a nocturnally illuminated riparian ecosystem

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    Aquatic and terrestrial ecosystems are linked by fluxes of carbon and nutrients in riparian areas. Processes that alter these fluxes may therefore change the diet and composition of consumer communities. We used stable carbon isotope (δ13C) analyses to test whether the increased abundance of aquatic prey observed in another study led to a dietary shift in riparian consumers in areas illuminated by artificial light at night (ALAN). We measured the contribution of aquatic-derived carbon to diets in riparian arthropods in experimentally lit and unlit sites along an agricultural drainage ditch in northern Germany. The δ13C signature of the spider Pachygnatha clercki (Tetragnathidae) was 0.7‰ lower in the ALAN-illuminated site in summer, indicating a greater assimilation of aquatic prey. Bayesian mixing models also supported higher intake of aquatic prey under ALAN in summer (34% versus 21%). In contrast, isotopic signatures for P. clercki (0.3‰) and Pardosa prativaga (0.7‰) indicated a preference for terrestrial prey in the illuminated site in summer. Terrestrial prey intake increased in spring for P. clerckii under ALAN (from 70% to 74%) and in spring and autumn for P. prativaga (from 68% to 77% and from 67% to 72%) and Opiliones (from 68% to 72%; 68% to 75%). This was despite most of the available prey (up to 80%) being aquatic in origin. We conclude that ALAN changed the diet of riparian secondary consumers by increasing the density of both aquatic and terrestrial prey. Dietary changes were species- and season-specific, indicating that the effects of ALAN may interact with phenology and feeding strategy. Because streetlights can occur in high density near freshwaters, ALAN may have widespread effects on aquatic-terrestrial ecosystem linkages
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