189 research outputs found

    Air quality management planning (AQMP)

    Get PDF
    In most urban areas of the world, particulate matter (PM) levels pose severe problems, addressed in several policy areas (air quality, climate change, and human health). PM presents multiple challenges due to the multitude of its sources, spanning many sectors of economic activity as well as nature, and due to the complexity of atmospheric processes involved in its transport and secondary formation. For the authorities, the goal is to assure minimal impacts of atmospheric PM levels, in practice represented by compliance with existing regulations and standards. This may be achieved through an air quality management plan (AQMP). In Northern America and in parts of Europe, comprehensive research programs have guided development of AQMP over the last forty years. This cumulated experience can be utilized by others who face the same problems, but have yet to develop their own substantial research base. The main purpose of the AQMP development process is to establish an effective and sound basis for planning and management of air quality in a selected area. This type of planning will ensure that significant sources of impacts are identified and controlled in a most cost-effective manner. The choice of tools, methods and input information is often dictated by their availability, and should be evaluated against current best practices. Important elements of the AQMP are the identification of sources and development of a complete emission inventory, the development and operation of an air quality monitoring programme, and the development and application of atmospheric dispersion models. Major task is to collect the necessary input data. The development of the AQMP will take into account: - Air Quality Management System (AQMS) requirements; - Operational and functional structure requirements; - Source identification through emission inventories; - Source reduction alternatives, which may be implemented; - Mechanisms for facilitating interdepartmental cooperation in order to assure that actions are being taken; - Institutional building and training requirements This paper offers a practical guide through the different parts of the air quality management and planning procedures

    Co-benefit and co-control studies in Norway

    Get PDF
    In both developing and industrialized countries, abatement of air pollution and mitigation of climate change have generally been treated separately. Co-benefits of air quality and climate change related policies are often addressed on national or supra-national level, to document that costs of policies are acceptable, especially when ancillary benefits are considered. On local or regional level, the focus until now has been mainly on air quality management, not considering benefits for climate change mitigation. Today’s air quality management requires integrated and coordinated measures where urban air quality planning includes also greenhouse gas (GHG) emissions and climate change issues. The tools available for investigating scenarios for reducing local impacts and health effect improvements can also be used to investigate cost effective actions aimed at reducing GHG emissions. This approach would lead to identification of strategies that consider co-benefits of climate and local air quality measures, and would both improve the health of people and give climate benefits at best possible costs. Approaches based on an existing air quality management tool, prepared for co-benefit studies in Norway as well as plans for co-control projects in China are presented in this paper. These approaches have the potential to focus on issues not included in traditional air pollution abatement studies

    Differences between patients' and clinicians' report of sleep disturbance: a field study in mental health care in Norway

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The aims of the study was to assess the prevalence of diagnosed insomnia and the agreement between patient- and clinician-reported sleep disturbance and use of prescribed hypnotic medication in patients in treatment for mental disorders.</p> <p>Methods</p> <p>We used three cross-sectional, multicenter data-sets from 2002, 2005, and 2008. Data-set 1 included diagnostic codes from 93% of all patients receiving treatment in mental health care in Norway (<it>N </it>= 40261). Data-sets 2 (<it>N </it>= 1065) and 3 (<it>N </it>= 1181) included diagnostic codes, patient- and clinician-reported sleep disturbance, and use of prescribed hypnotic medication from patients in 8 mental health care centers covering 10% of the Norwegian population.</p> <p>Results</p> <p>34 patients in data-set 1 and none in data-sets 2 and 3 had a diagnosis of insomnia as a primary or comorbid diagnosis. In data-sets 2 and 3, 42% and 40% of the patients reported sleep disturbance, whereas 24% and 13% had clinician-reported sleep disturbance, and 7% and 9% used hypnotics. Patients and clinicians agreed in 29% and 15% of the cases where the patient or the clinician or both had reported sleep disturbance. Positive predictive value (PPV) of clinicians' evaluations of patient sleep disturbance was 62% and 53%. When the patient reported sleep disturbance as one of their most prominent problems PPV was 36% and 37%. Of the patients who received hypnotic medication, 23% and 29% had neither patient nor clinician-rated sleep disturbance.</p> <p>Conclusion</p> <p>When patients meet the criteria for a mental disorder, insomnia is almost never diagnosed, and sleep disturbance is imprecisely recognized relative to the patients' experience of sleep disturbance.</p

    Search for resonances decaying into photon pairs in 139 fb−1 of pp collisions at √s = 13 TeV with the ATLAS detector

    Get PDF
    Searches for new resonances in the diphoton final state, with spin 0 as predicted by theories with an extended Higgs sector and with spin 2 using a warped extra-dimension benchmark model, are presented using 139 fb−1 of √ s =13 TeV pp collision data collected by the ATLAS experiment at the LHC. No significant deviation from the Standard Model is observed and upper limits are placed on the production cross-section times branching ratio to two photons as a function of the resonance mass.publishedVersio

    Measurement of the tt¯ tt¯ production cross section in pp collisions at √s = 13 TeV with the ATLAS detector

    Get PDF
    A measurement of four-top-quark production using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the Large Hadron Collider corresponding to an integrated luminosity of 139 fb−1 is presented. Events are selected if they contain a single lepton (electron or muon) or an opposite-sign lepton pair, in association with multiple jets. The events are categorised according to the number of jets and how likely these are to contain b-hadrons. A multivariate technique is then used to discriminate between signal and background events. The measured four-top-quark production cross section is found to be 26+17−15 fb, with a corresponding observed (expected) significance of 1.9 (1.0) standard deviations over the background-only hypothesis. The result is combined with the previous measurement performed by the ATLAS Collaboration in the multilepton final state. The combined four-top-quark production cross section is measured to be 24+7−6 fb, with a corresponding observed (expected) signal significance of 4.7 (2.6) standard deviations over the background-only predictions. It is consistent within 2.0 standard deviations with the Standard Model expectation of 12.0 ± 2.4 fb.publishedVersio

    Measurement of the CP-violating phase ϕs in B0s→J/ψϕ decays in ATLAS at 13 TeV

    Get PDF
    A measurement of the B0s→J/ψϕ decay parameters using 80.5fb−1 of integrated luminosity collected with the ATLAS detector from 13 TeV proton–proton collisions at the LHC is presented. The measured parameters include the CP-violating phase ϕs, the width difference ΔΓs between the B0s meson mass eigenstates and the average decay width Γs. The values measured for the physical parameters are combined with those from 19.2fb−1 of 7 and 8 TeV data, leading to the following: ϕs=−0.087±0.036 (stat.)±0.021 (syst.) rad ΔΓs=0.0657±0.0043 (stat.)±0.0037 (syst.) ps−1 Γs=0.6703±0.0014 (stat.)±0.0018 (syst.) ps−1 Results for ϕs and ΔΓs are also presented as 68% confidence level contours in the ϕs–ΔΓs plane. Furthermore the transversity amplitudes and corresponding strong phases are measured. ϕs and ΔΓs measurements are in agreement with the Standard Model predictions.publishedVersio

    Search for charginos and neutralinos in final states with two boosted hadronically decaying bosons and missing transverse momentum in pp collisions at √s=13  TeV with the ATLAS detector

    Get PDF
    A search for charginos and neutralinos at the Large Hadron Collider using fully hadronic final states and missing transverse momentum is reported. Pair-produced charginos or neutralinos are explored, each decaying into a high-pT Standard Model weak boson. Fully hadronic final states are studied to exploit the advantage of the large branching ratio, and the efficient rejection of backgrounds by identifying the high-pT bosons using large-radius jets and jet substructure information. An integrated luminosity of 139  fb−1 of proton-proton collision data collected by the ATLAS detector at a center-of-mass energy of 13 TeV is used. No significant excess is found beyond the Standard Model expectation. Exclusion limits at the 95% confidence level are set on wino or higgsino production with various assumptions about the decay branching ratios and the type of lightest supersymmetric particle. A wino (higgsino) mass up to 1060 (900) GeV is excluded when the lightest supersymmetry particle mass is below 400 (240) GeV and the mass splitting is larger than 400 (450) GeV. The sensitivity to high-mass winos and higgsinos is significantly extended relative to previous LHC searches using other final states.publishedVersio

    Search for R-parity-violating supersymmetry in a final state containing leptons and many jets with the ATLAS experiment using √s = 13 TeV proton–proton collision data

    Get PDF
    A search for R-parity-violating supersymmetry in final states characterized by high jet multiplicity, at least one isolated light lepton and either zero or at least three b-tagged jets is presented. The search uses 139fb−1 of s√=13 TeV proton–proton collision data collected by the ATLAS experiment during Run 2 of the Large Hadron Collider. The results are interpreted in the context of R-parity-violating supersymmetry models that feature gluino production, top-squark production, or electroweakino production. The dominant sources of background are estimated using a data-driven model, based on observables at medium jet multiplicity, to predict the b-tagged jet multiplicity distribution at the higher jet multiplicities used in the search. Machine-learning techniques are used to reach sensitivity to electroweakino production, extending the data-driven background estimation to the shape of the machine-learning discriminant. No significant excess over the Standard Model expectation is observed and exclusion limits at the 95% confidence level are extracted, reaching as high as 2.4 TeV in gluino mass, 1.35 TeV in top-squark mass, and 320 (365) GeV in higgsino (wino) mass.publishedVersio

    Search for lepton-flavor violation in Z-boson decays with Ï„ leptons with the ATLAS detector

    Get PDF
    A search for lepton-flavor-violating Z→eτ and Z→μτ decays with pp collision data recorded by the ATLAS detector at the LHC is presented. This analysis uses 139  fb−1 of Run 2 pp collisions at √s=13 TeV and is combined with the results of a similar ATLAS search in the final state in which the τ lepton decays hadronically, using the same data set as well as Run 1 data. The addition of leptonically decaying τ leptons significantly improves the sensitivity reach for Z→ℓτ decays. The Z→ℓτ branching fractions are constrained in this analysis to B(Z→eτ)<7.0×10−6 and B(Z→μτ)<7.2×10−6 at 95% confidence level. The combination with the previously published analyses sets the strongest constraints to date: B(Z→eτ)<5.0×10−6 and B(Z→μ)<6.5×10−6 at 95% confidence level.publishedVersio

    Search for new phenomena with top quark pairs in final states with one lepton, jets, and missing transverse momentum in pp collisions at √s = 13 TeV with the ATLAS detector

    Get PDF
    A search for new phenomena with top quark pairs in final states with one isolated electron or muon, multiple jets, and large missing transverse momentum is performed. Signal regions are designed to search for two-, three-, and four-body decays of the directly pair-produced supersymmetric partner of the top quark (stop). Additional signal regions are designed specifically to search for spin-0 mediators that are produced in association with a pair of top quarks and decay into a pair of dark-matter particles. The search is performed using the Large Hadron Collider proton-proton collision dataset at a centre-of-mass energy of √s = 13 TeV recorded by the ATLAS detector from 2015 to 2018, corresponding to an integrated luminosity of 139 fb−1. No significant excess above the Standard Model background is observed, and limits at 95% confidence level are set in the stop-neutralino mass plane and as a function of the mediator mass or the dark-matter particle mass. Stops are excluded up to 1200 GeV (710 GeV) in the two-body (three-body) decay scenario. In the four-body scenario stops up to 640 GeV are excluded for a stop-neutralino mass difference of 60 GeV. Scalar and pseudoscalar dark-matter mediators are excluded up to 200 GeV when the coupling strengths of the mediator to Standard Model and dark-matter particles are both equal to one and when the mass of the dark-matter particle is 1 GeV.publishedVersio
    • …
    corecore