22 research outputs found

    Constraints on the density dependence of the symmetry energy

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    Current status and future experimental plans for constraining the symmetry energy at supra-normal densities are presented. A special emphasis is put on significance of the results obtained by the ASY-EOS Collaboration in a broader astrophysical context, including the recent interpretations of the first LIGO and Virgo GW170817 gravitational wave signal. The plans for a high energy campaign at FAIR using the NeuLAND and the KRAB detectors will be outlined.Comment: Proceedings of the IWM-EC 2018 Conferenc

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    Microbial Source Tracking: Current Methodology and Future Directions

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    Maintenance of the microbiological quality and safety of water systems used for drinking, for recreating, and in the harvesting of seafood is imperative, as contamination of these systems can exact high risks to human health as well as result in significant economic losses due to closures of beaches and shellfish harvesting areas. Waters contaminated with human feces are generally regarded as a greater risk to human health, as they are more likely to contain human-specific enteric pathogens, including Salmonella enterica serovar Typhi, Shi-gella spp., hepatitis A virus, and Norwalk-group viruses. Ani-mals can also serve as reservoirs for a variety of enteric patho-gens (e.g., various serotypes of Salmonella, Escherichia coli, and Cryptosporidium spp.). Understanding the origin of fecal pollution is paramount in assessing associated health risks as well as the actions necessary to remedy the problem while i

    Detection of Human-Derived Fecal Pollution in Environmental Waters by Use of a PCR-Based Human Polyomavirus Assay

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    Regulatory agencies mandate the use of fecal coliforms, Escherichia coli or Enterococcus spp., as microbial indicators of recreational water quality. These indicators of fecal pollution do not identify the specific sources of pollution and at times underestimate health risks associated with recreational water use. This study proposes the use of human polyomaviruses (HPyVs), which are widespread among human populations, as indicators of human fecal pollution. A method was developed to concentrate and extract HPyV DNA from environmental water samples and then to amplify it by nested PCR. HPyVs were detected in as little as 1 μl of sewage and were not amplified from dairy cow or pig wastes. Environmental water samples were screened for the presence of HPyVs and two additional markers of human fecal pollution: the Enterococcus faecium esp gene and the 16S rRNA gene of human-associated Bacteroides. The presence of human-specific indicators of fecal pollution was compared to fecal coliform and Enterococcus concentrations. HPyVs were detected in 19 of 20 (95%) samples containing the E. faecium esp gene and Bacteroides human markers. Weak or no correlation was observed between the presence/absence of human-associated indicators and counts of indicator bacteria. The sensitivity, specificity, and correlation with other human-associated markers suggest that the HPyV assay could be a useful predictor of human fecal pollution in environmental waters and an important component of the microbial-source-tracking “toolbox.

    Quantification of Human Polyomaviruses JC Virus and BK Virus by TaqMan Quantitative PCR and Comparison to Other Water Quality Indicators in Water and Fecal Samplesâ–¿

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    In the United States, total maximum daily load standards for bodies of water that do not meet bacterial water quality standards are set by each state. The presence of human polyomaviruses (HPyVs) can be used as an indicator of human-associated sewage pollution in these waters. We have developed and optimized a TaqMan quantitative PCR (QPCR) assay based on the conserved T antigen to both quantify and simultaneously detect two HPyVs; JC virus and BK virus. The QPCR assay was able to consistently quantify ≥10 gene copies per reaction and is linear over 5 orders of magnitude. HPyVs were consistently detected in human waste samples (57 of 64) and environmental waters with known human fecal contamination (5 of 5) and were not amplified in DNA extracted from 127 animal waste samples from 14 species. HPyV concentrations in sewage decreased 81.2 and 84.2% over 28 days incubation at 25 and 35°C, respectively. HPyVs results were compared to Escherichia coli, fecal coliform, and enterococci concentrations and the presence of three other human-associated microbes: Bacteroidetes, Methanobrevibacter smithii, and adenovirus. HPyVs were the most frequently detected of these in human and contaminated environmental samples and were more human specific than the Bacteroidetes (HF183) or M. smithii. HPyVs and M. smithii more closely mimicked the persistence of adenovirus in sewage than the other microbes. The use of this rapid and quantitative assay in water quality research could help regulatory agencies to identify sources of water pollution for improved remediation of contaminated waters and ultimately protect humans from exposure to pathogens
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