84 research outputs found

    Multi-year interlaboratory exercises for the analysis of illicit drugs and metabolites in wastewater:development of a quality control system

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    Thirty-seven laboratories from 25 countries present the development of an inter-laboratory testing scheme for the analysis of seven illicit drug residues in standard solutions, tap- and wastewater. Almost 10 000 concentration values were evaluated: triplicates of up to five samples and 26 laboratories per year. The setup was substantially improved with experiences gained across the six repetitions (e.g. matrix type, sample conditions, spiking levels). From this, (pre-)analytical issues (e.g. pH adjustment, filtration) were revealed for specific analytes which resulted in formulation of best-practice protocols for inter-laboratory setup and analytical procedures. The results illustrate the effectiveness of the inter-laboratory setup to assess laboratory performance in the framework of wastewater-based epidemiology. The exercise proved that measurements of laboratories were of high quality (>80% satisfactory results for six out of seven analytes) and that analytical follow-up is important to assist laboratories in improving robustness of wastewater-based epidemiology results

    Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model

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    We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society

    Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

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    The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T<5.58×10-8, Ω0V<6.35×10-8, and Ω0S<1.08×10-7 at a reference frequency f0=25 Hz. © 2018 American Physical Society

    Erratum: "A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo" (2021, ApJ, 909, 218)

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    Production of Υ(nS) mesons in Pb+Pb and pp collisions at 5.02 TeV

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    A measurement of the production of vector bottomonium states, Υ ( 1S ) , Υ ( 2S ) , and Υ ( 3S ) , in Pb + Pb and p p collisions at a center-of-mass energy per nucleon pair of 5.02 TeV is presented. The data correspond to integrated luminosities of 1.38 nb − 1 of Pb + Pb data collected in 2018, 0.44 nb − 1 of Pb + Pb data collected in 2015, and 0.26 fb − 1 of p p data collected in 2017 by the ATLAS detector at the Large Hadron Collider. The measurements are performed in the dimuon decay channel for transverse momentum p μ μ T &lt; 30 GeV , absolute rapidity | y μ μ | &lt; 1.5 , and Pb + Pb event centrality 0–80%. The production rates of the three bottomonium states in Pb + Pb collisions are compared with those in p p collisions to extract the nuclear modification factors as functions of event centrality, p μ μ T , and | y μ μ | . In addition, the suppression of the excited states relative to the ground state is studied. The results are compared with theoretical model calculations

    Home Hygiene and Prevention of Infections

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    Health is wealth - a famous proverb that almost everyone has heard of but may not have fully understood its essence. Health comes from maintaining cleanliness and hygiene which starts from home and expands to workplaces and public areas. By practicing hygiene in the home and everyday life settings, it will have impact significantly in reducing the global burden of infectious diseases that kills over 17 million people a year. Mainly caused by microorganisms, infections can easily spread by direct and indirect contact. Common infectious diseases include chickenpox, common cold, malaria and pertussis. These diseases tend to have specific symptoms such as fever, diarrhoea, fatigue and muscle aches. In institutional settings, such as schools and child-cares settings, information relating hand hygiene is routine. However, the home environment is one of the potential sources of transmission of infectious diseases. This situation, of course, needs to be re-evaluated and the promotion of home hygiene should be encouraged. Positive correlation has been found between home hygiene practices and risk of disease transmission in homes where the first line of defence against infectious diseases is cleaning and disinfecting plus maintaining good hand hygiene. But, the implementation for an effective policy to monitor home hygiene is rather complex due to varying determinants of health. In a nutshell, proper home hygiene and cleaning practices lead to reduced risk of spreading infectious diseases. They should form the key issues in the practice of health promotion in the community and institutions

    Tracking the hydrodynamic behavior of fine sediment using particle image velocimetry

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    Siltation, or sediment pollution, is a cause for water pollution by fine particles, which are categorized as clay and silt. With the increasing concentration and accumulation of suspended sediments (<63 µm) siltation occurs, which is most often caused by soil erosion or sediment spill. The high rate of suspended particles causes the ecological degradation of water ecosystems. Thus, studying the hydrodynamic behavior of fine sediments is essential. Directly evaluating fine particle suspension and deposition can be expensive and limiting. The aim of this study is to present a novel, direct view of the hydrodynamic behavior of fine sediment in retention structures with different hydraulic features using particle image velocimetry (PIV). The setup is designed to identify fine particle displacement by capturing images with a charge-coupled device camera and Nd-YAG laser lighting. The results were obtained from a designed sediment basin, to which water with 15 % fine soil (<63 µm) concentration was added and which was subsequently seeded with fluorescent polymer particles (20–50 µm). New knowledge of a direct map of the hydraulic behavior of fine sediment is presented. According to the results, the flow rate modifies the velocity and direction of fine particles, while at the bottom of the basin towards the outlet, the re-suspension rate increases at a higher flow rate
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