417 research outputs found

    Detection of Salmonella Enteritidis in Pooled Poultry Environmental Samples Using a Serotype-Specific Real-Time–Polymerase Chain Reaction Assay

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    While real-time–polymerase chain reaction (RT PCR) has been used as a rapid test for detection of Salmonella Enteritidis in recent years, little research has been done to assess the feasibility of pooling poultry environmental samples with aSalmonella Enteritidis–specific RT PCR assay. Therefore the objective of this study was to compare RT PCR SalmonellaEnteritidis detection in individual and pooled (in groups of two, three, and four) poultry environmental drag swab samples to traditional cultural methods. The drag swabs were collected from poultry facilities previously confirmed positive forSalmonella Enteritidis and were cultured according to National Poultry Improvement Plan guidelines. Initial, SalmonellaEnteritidis–specific RT PCR assay threshold cycle cutoff values of ≀36, ≀30, and ≀28 were evaluated in comparison to culture. The average limit of detection of the RT PCR assay was 2.4 × 103 colony-forming units (CFUs)/ml, which corresponded to an average threshold cycle value of 36.6. Before enrichment, samples inoculated with concentrations from 102 to 105 CFUs/ml were detected by RT PCR, while after enrichment, samples inoculated from 100 to 105 CFUs/ml were detected by RT PCR. Threshold cycle cutoff values were used in the subsequent field trial from which Salmonella Enteritidis was cultured in 7 of 208 environmental samples (3.4%). Individual samples were 99.0%, 100%, and 100% in agreement with the RT PCR at threshold cycle (Ct) cutoff values of ≀36, ≀30, and ≀28 respectively. The agreement for pooled samples also followed the same trend with highest agreement at Ct ≀ 28 (pool of 2  =  100.0%, pool of 3  =  100.0%, pool of 4  =  100.0%), midrange agreement at Ct ≀ 30 (pool of 2  =  99.0%, pool of 3  =  100.0%, pool of 4  =  100.0%), and lowest agreement at Ct ≀ 36 (pool of 2  =  98.1%, pool of 3  =  97.1%, pool of 4  =  98.1%). In conclusion, regardless of the level of pooling after tetrathionate enrichment, sensitivity was very good, and results would be comparable to what would have been found with individual culture or individual RT PCR at Ct ≀ 36

    Ring test evaluation of the detection of influenza A virus in swine oral fluids by real-time reverse-transcription polymerase chain reaction and virus isolation

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    The probability of detecting influenza A virus (IAV) in oral fluid (OF) specimens was calculated for each of 13 assays based on real-time reverse-transcription polymerase chain reaction (rRT-PCR) and 7 assays based on virus isolation (VI). The OF specimens were inoculated with H1N1 or H3N2 IAV and serially diluted 10-fold (10(-1) to 10(-8)). Eight participating laboratories received 180 randomized OF samples (10 replicates × 8 dilutions × 2 IAV subtypes plus 20 IAV-negative samples) and performed the rRT-PCR and VI procedure(s) of their choice. Analysis of the results with a mixed-effect logistic-regression model identified dilution and assay as variables significant (P \u3c 0.0001) for IAV detection in OF by rRT-PCR or VI. Virus subtype was not significant for IAV detection by either rRT-PCR (P = 0.457) or VI (P = 0.101). For rRT-PCR the cycle threshold (Ct) values increased consistently with dilution but varied widely. Therefore, it was not possible to predict VI success on the basis of Ct values. The success of VI was inversely related to the dilution of the sample; the assay was generally unsuccessful at lower virus concentrations. Successful swine health monitoring and disease surveillance require assays with consistent performance, but significant differences in reproducibility were observed among the assays evaluated

    Study protocol: national research partnership to improve primary health care performance and outcomes for Indigenous peoples

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    Background Strengthening primary health care is critical to reducing health inequity between Indigenous and non-Indigenous Australians. The Audit and Best practice for Chronic Disease Extension (ABCDE) project has facilitated the implementation of modern Continuous Quality Improvement (CQI) approaches in Indigenous community health care centres across Australia. The project demonstrated improvements in health centre systems, delivery of primary care services and in patient intermediate outcomes. It has also highlighted substantial variation in quality of care. Through a partnership between academic researchers, service providers and policy makers, we are now implementing a study which aims to 1) explore the factors associated with variation in clinical performance; 2) examine specific strategies that have been effective in improving primary care clinical performance; and 3) work with health service staff, management and policy makers to enhance the effective implementation of successful strategies. Methods/Design The study will be conducted in Indigenous community health centres from at least six States/Territories (Northern Territory, Western Australia, New South Wales, South Australia, Queensland and Victoria) over a five year period. A research hub will be established in each region to support collection and reporting of quantitative and qualitative clinical and health centre system performance data, to investigate factors affecting variation in quality of care and to facilitate effective translation of research evidence into policy and practice. The project is supported by a web-based information system, providing automated analysis and reporting of clinical care performance to health centre staff and management. Discussion By linking researchers directly to users of research (service providers, managers and policy makers), the partnership is well placed to generate new knowledge on effective strategies for improving the quality of primary health care and fostering effective and efficient exchange and use of data and information among service providers and policy makers to achieve evidence-based resource allocation, service planning, system development, and improvements of service delivery and Indigenous health outcomes.Ross Bailie, Damin Si, Cindy Shannon, James Semmens, Kevin Rowley, David J Scrimgeour, Tricia Nage, Ian Anderson, Christine Connors, Tarun Weeramanthri, Sandra Thompson, Robyn McDermott, Hugh Burke, Elizabeth Moore, Dallas Leon, Richard Weston, Haylene Grogan, Andrew Stanley and Karen Gardne

    Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

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    MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

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    Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe

    Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

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    The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe

    Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

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    Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (Ό̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ÂŻ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ÂŻ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),Ό̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| &lt; 0.03 at 95% confidence level. [Figure not available: see fulltext.

    An embedding technique to determine ττ backgrounds in proton-proton collision data

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    An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

    Search for Physics beyond the Standard Model in Events with Overlapping Photons and Jets

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    Results are reported from a search for new particles that decay into a photon and two gluons, in events with jets. Novel jet substructure techniques are developed that allow photons to be identified in an environment densely populated with hadrons. The analyzed proton-proton collision data were collected by the CMS experiment at the LHC, in 2016 at root s = 13 TeV, and correspond to an integrated luminosity of 35.9 fb(-1). The spectra of total transverse hadronic energy of candidate events are examined for deviations from the standard model predictions. No statistically significant excess is observed over the expected background. The first cross section limits on new physics processes resulting in such events are set. The results are interpreted as upper limits on the rate of gluino pair production, utilizing a simplified stealth supersymmetry model. The excluded gluino masses extend up to 1.7 TeV, for a neutralino mass of 200 GeV and exceed previous mass constraints set by analyses targeting events with isolated photons.Peer reviewe
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