81 research outputs found

    Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

    Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

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    The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

    Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

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    BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

    Measurement of the cross-section for b-jets produced in association with a Z boson at root s=7 TeV with the ATLAS detector ATLAS Collaboration

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    A measurement is presented of the inclusive cross-section for b-jet production in association with a Z boson in pp collisions at a centre-of-mass energy of root s = 7 TeV. The analysis uses the data sample collected by the ATLAS experiment in 2010, corresponding to an integrated luminosity of approximately 36 pb(-1). The event selection requires a Z boson decaying into high P-T electrons or muons, and at least one b-jet, identified by its displaced vertex, with transverse momentum p(T) > 25 GeV and rapidity vertical bar y vertical bar < 2.1. After subtraction of background processes, the yield is extracted from the vertex mass distribution of the candidate b-jets. The ratio of this cross-section to the inclusive Z cross-section (the average number of b-jets per Z event) is also measured. Both results are found to be in good agreement with perturbative QCD predictions at next-to-leading order

    Measurement of charged-particle event shape variables in inclusive root(s)=7 TeV proton-proton interactions with the ATLAS detector

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    The measurement of charged-particle event shape variables is presented in inclusive inelastic pp collisions at a center-of-mass energy of 7 TeV using the ATLAS detector at the LHC. The observables studied are the transverse thrust, thrust minor, and transverse sphericity, each defined using the final-state charged particles' momentum components perpendicular to the beam direction. Events with at least six charged particles are selected by a minimum-bias trigger. In addition to the differential distributions, the evolution of each event shape variable as a function of the leading charged-particle transverse momentum, charged-particle multiplicity, and summed transverse momentum is presented. Predictions from several Monte Carlo models show significant deviations from data

    The embryo as moral work object: PGD/IVF staff views and experiences

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    Copyright @ 2008 the authors. This article is available in accordance with the Creative Commons Deed, Attribution 2.5, see http://creativecommons.org/licenses/by-nc-nd/2.5/deed.en_CA.We report on one aspect of a study that explored the views and experiences of practitioners and scientists on social, ethical and clinical dilemmas encountered when working in the field of preimplantation genetic diagnosis (PGD) for serious genetic disorders. The study produced an ethnography based on observation, interviews and ethics discussion groups with staff from two PGD/IVF Units in the UK. We focus here on staff perceptions of work with embryos that entails disposing of ‘affected’ or ‘spare’ embryos or using them for research. A variety of views were expressed on the ‘embryo question’ in contrast to polarised media debates. We argue that the prevailing policy acceptance of destroying affected embryos, and allowing research on embryos up to 14 days leaves some staff with rarely reported, ambivalent feelings. Staff views are under-researched in this area and we focus on how they may reconcile their personal moral views with the ethical framework in their field. Staff construct embryos in a variety of ways as ‘moral work objects’. This allows them to shift attention between micro-level and overarching institutional work goals, building on Casper's concept of ‘work objects’ and focusing on negotiation of the social order in a morally contested field.The Wellcome Trust Biomedical Ethics Programme, who funded the projects‘Facilitating choice, framing choice: the experience of staff working in pre-implantation genetic diagnosis’ (no: 074935), and ‘Ethical Frameworks for Embryo Donation:the views and practices of IVF/PGD staff’ (no: 081414)

    KC 4.1: Rural heritage and urban-rural linkages in the ICOMOS SDGs Policy Guidance

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    This Knowledge Café aims to provide a discussion platform to contribute to the drafting of a new ICOMOS SDGs Policy Guidance, from the perspective of rural heritage, landscapes and rural-urban linkages. While 50%-plus of global populations are urban dwellers, we tend to forget that the other half dwell in rural places. One of the 7 Priority Actions of the ICOMOS SDGs Working Group in 2018 is the preparation of a consolidated policy statement, as an effective tool for advocacy and communication to wider society and the development world. Based on the need to boost the role of cultural heritage in sustainable development processes, this would be a robust Policy Guidance document, serving to improve the recognition of the role of cultural heritage protection, particularly as defined by SDG 11.4 and the New Urban Agenda. The ICOMOS SDGs Working Group aims to launch this document at the 10th World Urban Forum in 2020 and at the High-Level Political Forum in 2021. The new Policy Guidance aims to emphasize “heritage as a resource, a strategic opportunity”, using the framework of the 3 dimensions of sustainability, economic, social, environmental, and propose adding the 4th dimension of ‘culture’ through an appropriate approach. The document should be based on solid scientific expertise sourced from ICOMOS membership. The Symposium on Rural Heritage: Landscapes and Beyond is a prime opportunity to involve some of this membership, ensuring a diverse and inclusive range of expertise in heritage informs the Policy Guidance. Rural heritage and landscapes, including rural-urban linkages, have great relevance for the intersection of cultural heritage and sustainable development, touching on many SDGs and issues raised in the New Urban Agenda, not to mention the Historic Urban Landscape Recommendation. To cite some examples of this inter-connectedness, the “inter-related categories of continuity and change” addressed during the Symposium, provide the following links: - under ‘Rural Culture’ to SDG 11.4 (change management for tangible rural heritage), SDG 1.5, 2.4, 11.5, 11.b, 13.1 (risk of loss of intangible rural traditions/ practices), SDG 8.9, SDG 12.b (rural cultural tourism), SDG 16.7, 16.a, 17.9, 17.15, 17.17 (identity of people and places); - under ‘Rural economics’ to SDG 1 (poverty eradication), SDG2 (food security), SDG3 (rural agricultural heritage), SDG 8 (improvement of markets and opportunities for rural traditional tools, techniques and rural heritage tourism), SDG 8 (infrastructure, services to small enterprises), SDG 11 (spatial form, territorial policies); - under ‘Rural Environment’ to SDG 6 (water), 13 and 15 (desertification, climate-induced severe weather events, biodiversity, forest management); and - under ‘Rural Society’ to SDG 1 (poverty alleviation) SDG 2 (agriculture), SDG 3.8, 3.c (health services), SDG 16, 17 (bottom-up governance). - Some case studies from ‘Moroccan Rural Heritage’ can be proposed during the session from participants who may have relevant knowledge, to demonstrate these links. The Knowledge Café will feature two speakers, Ege Yildirim and Patricia O’Donnell, giving the conceptual framework of the session, followed by Ilaria Rosetti presenting the method of open discussion, whereby breakout groups (e.g. 3-4 groups of 5-6) can discuss the links of rural heritage issues to the various 17 Goals and Targets under them, concluding with short reporting from each group, to be compiled and disseminated later by the conveners

    SARS-CoV-2 lineage dynamics in England from September to November 2021: high diversity of Delta sub-lineages and increased transmissibility of AY.4.2

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    Abstract Background Since the emergence of SARS-CoV-2, evolutionary pressure has driven large increases in the transmissibility of the virus. However, with increasing levels of immunity through vaccination and natural infection the evolutionary pressure will switch towards immune escape. Genomic surveillance in regions of high immunity is crucial in detecting emerging variants that can more successfully navigate the immune landscape. Methods We present phylogenetic relationships and lineage dynamics within England (a country with high levels of immunity), as inferred from a random community sample of individuals who provided a self-administered throat and nose swab for rt-PCR testing as part of the REal-time Assessment of Community Transmission-1 (REACT-1) study. During round 14 (9 September–27 September 2021) and 15 (19 October–5 November 2021) lineages were determined for 1322 positive individuals, with 27.1% of those which reported their symptom status reporting no symptoms in the previous month. Results We identified 44 unique lineages, all of which were Delta or Delta sub-lineages, and found a reduction in their mutation rate over the study period. The proportion of the Delta sub-lineage AY.4.2 was increasing, with a reproduction number 15% (95% CI 8–23%) greater than the most prevalent lineage, AY.4. Further, AY.4.2 was less associated with the most predictive COVID-19 symptoms (p = 0.029) and had a reduced mutation rate (p = 0.050). Both AY.4.2 and AY.4 were found to be geographically clustered in September but this was no longer the case by late October/early November, with only the lineage AY.6 exhibiting clustering towards the South of England. Conclusions As SARS-CoV-2 moves towards endemicity and new variants emerge, genomic data obtained from random community samples can augment routine surveillance data without the potential biases introduced due to higher sampling rates of symptomatic individuals. </jats:sec

    The ATLAS Inner Detector commissioning and calibration

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    The ATLAS Collaboration

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