1,654 research outputs found

    Evaluation of Twitter data for an emerging crisis: an application to the first wave of COVID-19 in the UK

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    In the absence of nationwide mass testing for an emerging health crisis, alternative approaches could provide necessary information efficiently to aid policy makers and health bodies when dealing with a pandemic. The following work presents a methodology by which Twitter data surrounding the first wave of the COVID-19 pandemic in the UK is harvested and analysed using two main approaches. The first is an investigation into localized outbreak predictions by developing a prototype early-warning system using the distribution of total tweet volume. The temporal lag between the rises in the number of COVID-19 related tweets and officially reported deaths by Public Health England (PHE) is observed to be 6–27 days for various UK cities which matches the temporal lag values found in the literature. To better understand the topics of discussion and attitudes of people surrounding the pandemic, the second approach is an in-depth behavioural analysis assessing the public opinion and response to government policies such as the introduction of face-coverings. Using topic modelling, nine distinct topics are identified within the corpus of COVID-19 tweets, of which the themes ranged from retail to government bodies. Sentiment analysis on a subset of mask related tweets revealed sentiment spikes corresponding to major news and announcements. A Named Entity Recognition (NER) algorithm is trained and applied in a semi-supervised manner to recognise tweets containing location keywords within the unlabelled corpus and achieved a precision of 81.6%. Overall, these approaches allowed extraction of temporal trends relating to PHE case numbers, popular locations in relation to the use of face-coverings, and attitudes towards face-coverings, vaccines and the national ‘Test and Trace’ scheme

    Search for direct production of charginos, neutralinos and sleptons in final states with two leptons and missing transverse momentum in pp collisions at √s = 8TeV with the ATLAS detector

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    Searches for the electroweak production of charginos, neutralinos and sleptons in final states characterized by the presence of two leptons (electrons and muons) and missing transverse momentum are performed using 20.3 fb−1 of proton-proton collision data at s√ = 8 TeV recorded with the ATLAS experiment at the Large Hadron Collider. No significant excess beyond Standard Model expectations is observed. Limits are set on the masses of the lightest chargino, next-to-lightest neutralino and sleptons for different lightest-neutralino mass hypotheses in simplified models. Results are also interpreted in various scenarios of the phenomenological Minimal Supersymmetric Standard Model

    Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector

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    The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry

    The optimal choice of privatizing state-owned enterprises: A political economic model

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    We study the choices of two types of maximizing Public Servants over how far to carry privatization of industries and in what order to privatize. Two stylizations of the Public Servant's objectives are considered, a Niskanen-style Bureaucrat who maximizes a surplus budget subject to the constraint of staying in office, and a Populist who maximizes popularity/consumer welfare subject to the constraint of a balanced budget. Other things being equal, the Bureaucrat will privatize the sector (firms) with the least market power and the largest subsidy first. The Populist will adopt the same policy, if the marginal costs of products in the private sectors are not too high with respect to the marginal utilities. If the marginal costs are too high, however, the Populist will privatize the sector with the largest market power first. We also show that privatization is easier and faster in less democratic societies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45520/1/11127_2004_Article_BF00136520.pd

    Deployment of mating disruption dispensers before and after first seasonal male flights for the control of Aonidiella aurantii in citrus

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    The rejection of citrus fruit caused by infestations of the California red scale (CRS), Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae), raises concerns about its management. This fact has led to the introduction of new integrated control methods in citrus orchards, including the implementation of techniques based on pheromones. Previous works described efficient mating disruption pheromone dispensers to control A. aurantii in the Mediterranean region. The main aims of the present study were to adjust the timing of dispenser applications and study the importance of controlling the early first generation of A. aurantii by testing two different application dates: before and after the first CRS male flight. The efficacy of the different mating disruption strategies was tested during 2010 in an experimental orchard and these results were confirmed during 2011 in a commercial citrus farm. Results showed that every mating disruption strategy achieved significantly lower male captures in monitoring pheromone traps compared with untreated plots, as well as mean fruit infestation reductions of about 80 %. The control of the first CRS generation is not essential for achieving a good efficacy as demonstrated in two locations with different pest pressure. The late application of MD dispensers before the second CRS male flight has proven to be effective, suggesting a new advantageous way to apply mating disruption.The authors want to thank Fernando Alfaro from Denia, Antonio Caballero, and Javier Macias from Rio Tinto Fruit S.A. (Huelva, Spain) for field support. We also thank Ecologia y Proteccion Agricola SL for the pheromone supply. This work has been funded by the Spanish Ministry of Science and Innovation (project AGL2009-10725) and Agroalimed Foundation. The translation of this paper was funded by the Universidad Politecnica de Valencia (Spain).Vacas González, S.; Alfaro Cañamás, C.; Primo Millo, J.; Navarro-Llopis, V. (2015). Deployment of mating disruption dispensers before and after first seasonal male flights for the control of Aonidiella aurantii in citrus. Journal of Pest Science. 88(2):321-329. https://doi.org/10.1007/s10340-014-0623-1S321329882Avidov Z, Balshin M, Gerson U (1970) Studies on Aphytis coheni, a parasite of the California red scale, Aonidiella aurantii in Israel. Biocontrol 15:191–207Barzakay I, Hefetz A, Sternlicht M, Peleg BA, Gokkes M, Singer G, Geffen D, Kronenberg S (1986) Further field trials on management of the California red scale, Aonidiella aurantii, by mating disruption with its sex-pheromone. Phytoparasitica 14:160–161Bedford ECG (1996) Problems which we face in bringing red scale, Aonidiella aurantii (Maskell), under biological control in citrus in South Africa. 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    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector