1,101 research outputs found

    Anisotropic a posteriori error estimate for the virtual element method

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    We derive an anisotropic a posteriori error estimate for the adaptive conforming virtual element approximation of a paradigmatic two-dimensional elliptic problem. In particular, we introduce a quasi-interpolant operator and exploit its approximation results to prove the reliability of the error indicator. We design and implement the corresponding adaptive polygonal anisotropic algorithm. Several numerical tests assess the superiority of the proposed algorithm in comparison with standard polygonal isotropic mesh refinement schemes

    Preliminary data related to the effect of climacostol produced by the freshwater ciliate climacostomum virens on human adenovirus

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    The new epidemiological scenario has so far focused on the environmental circulation of human viral pathogens. Owing to the side effects of chemical disinfectants, there is an increasing need for knowledge on the use of virucidal compounds, especially those of a natural origin. Climacostol is a molecule produced by a freshwater ciliate and it exhibits activity against bacterial and fungal pathogens. We thus also speculated that there might be an effect on viral viability, which has never been tested. To evaluate such activity, we chose human adenovirus (HAdV), which is representative of waterborne viruses. We conducted experiments using HAdV serotype 5, whose titer was determined by infecting HeLa cell cultures. HAdV5 was shown to be sensitive to climacostol at a concentration of 0.0002 mg/mL, with an approximate 3 Log10 reduction when the initial titer of HAdV5 was approximately 104 and 103 TCID50/mL. These preliminary results could be an important starting point for further research aimed at improving the characterization of climacostol activity under different experimental conditions and against various viruses, including enveloped ones (i.e., the coronavirus). The production of climacostol by a protist living in fresh water also suggests a possible application in the activated sludge of wastewater treatment plants

    Cleaning activity among Labridae in the Azores: the rainbow wrasse Coris julis and the Azorean blue wrasse Centrolabrus caeruleus

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    Copyright © Cambridge University Press 2009.Cleaning interactions among the rainbow wrasse Coris julis and the azorean blue wrasse Centrolabrus caeruleus are presented with photographic registers, as well as the first record of the latter cleaning conspecifics from Azorean shallow rocky reefs

    Rocky reef fish community structure in two Azorean islands (Portugal) central North Atlantic

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    Copyright © Cambridge University Press 2010.The community structure of shallow rocky reef fish fauna of the Azores Archipelago is described from underwater visual censuses carried out at eight areas (Terceira and Corvo Islands). A total of 52 fish species from 26 different families was observed, and the ten most abundant fish corresponded to 82.7% of all fish. Trophic categories are given for observed species with comments on distribution and densities along sampled depth strata. Mean densities along sampled strata were tested for significant differences. Sparidae, Labridae and Carangidae were the most speciose families being Diplodus sargus, Pagellus acarne, Coris julis, Thalassoma pavo and Tripterygion delaisi the most abundant species that consequently also accounted for the highest densities

    Patient and Provider Perspectives on How Trust Influences Maternal Vaccine Acceptance Among Pregnant Women in Kenya

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    Background Pregnant women and newborns are at high risk for infectious diseases. Altered immunity status during pregnancy and challenges fully vaccinating newborns contribute to this medical reality. Maternal immunization is a strategy to protect pregnant women and their newborns. This study aimed to find out how patient-provider relationships affect maternal vaccine uptake, particularly in the context of a lower middle- income country where limited research in this area exists. Methods We conducted semi-structured, in-depth narrative interviews of both providers and pregnant women from four sites in Kenya: Siaya, Nairobi, Mombasa, and Marsabit. Interviews were conducted in either English or one of the local regional languages. Results We found that patient trust in health care providers (HCPs) is integral to vaccine acceptance among pregnant women in Kenya. The HCP-patient relationship is a fiduciary one, whereby the patients’ trusts is primarily rooted in the provider’s social position as a person who is highly educated in matters of health. Furthermore, patient health education and provider attitudes are crucial for reinstating and fostering that trust, especially in cases where trust was impeded by rumors, community myths and misperceptions, and religious and cultural factors. Conclusion Patient trust in providers is a strong facilitator contributing to vaccine acceptance among pregnant women in Kenya. To maintain and increase immunization trust, providers have a critical role in cultivating a positive environment that allows for favorable interactions and patient health education. This includes educating providers on maternal immunizations and enhancing knowledge of effective risk communication tactics in clinical encounters

    Global occurrence of Torque teno virus in water systems

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    Bacterial indicator organisms are used globally to assess the microbiological safety of waters. However, waterborne viral outbreaks have occurred in drinking water systems despite negative bacterial results. Using viral markers may therefore provide more accurate health risk assessment data. In this study, fecal, wastewater, stormwater, surface water (fresh and salt), groundwater, and drinking water samples were analyzed for the presence or concentration of traditional indicators, innovative indicators and viral markers. Samples were obtained in the United States, Italy, and Australia and results compared to those reported for studies conducted in Asia and South America as well. Indicators included total coliforms, Escherichia coli, enterococci, male-specific coliphages, somatic coliphages and microviradae. Viral markers included adenovirus, polyomavirus, and a potential new surrogate, Torque teno virus (TTV). TTV was more frequently found in wastewaters (38-100%) and waters influenced by waste discharges (25%) than in surface waters used as drinking water sources (5%). TTV was also specific to human rather than animal feces. While TTV numbers were strongly correlated to other viral markers in wastewaters, suggesting its utility as a fecal contamination marker, data limitations and TTV presence in treated drinking waters demonstrates that additional research is needed on this potential viral indicator

    approach to a water safety plan for recreational waters disinfection of a drainage pumping station as an unconventional point source of fecal contamination

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    Abstract In the context of the management of bathing water quality, the intermittent contamination of rainwater drainage pumps (unconventional point sources) could be controlled by peracetic acid disinfection. Thus, a field experimental study was carried out to set up a water safety plan, determining the monitoring parameters and the critical limit for corrective actions. With a 0.5 mg/l dosage, the average logarithmic microbial reduction was 0.50 ± 0.48 for Escherichia coli (EC) and 0.43 ± 0.54 for intestinal enterococci. Among the chemical and physical parameters that could be monitored in real time, the oxidation–reduction potential was the only one able to predict the microbial concentration discharged from a drainage pump and the logarithmic abatement of EC. Considering the possible impact of this source on bathing waters in terms of additional risk of gastrointestinal infections, the critical limit for continuous monitoring was established using a quantitative microbial risk assessment (QMRA) model
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