1,645 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. Proc Int Soc Citriculture 1:485–492Campos-Rivela JM, Martínez-Ferrer MT, Fibla-Queralt JM (2012) Population dynamics and seasonal trend of California red scale (Aonidiella aurantii Maskell) in citrus in Northern Spain. Span J Agric Res 10:198–208Collins PJ, Lambkin TM, Bodnaruk P (1994) Suspected resistance to methidation in Aonidiella aurantii (Maskell) (Homoptera: diaspididae) from Queensland. J Aust Entomol Soc 33:325–326Corma A, Muñoz-Pallares J, Primo-Yufera E (1999) Production of semiochemical emitters having a controlled emission speed which are based on inorganic molecular sieves. World Patent WO9944420Corma A, Muñoz-Pallares J, Primo-Yufera E (2000) Emitter of semiochemical substances supported on a sepiolite, preparation process and applications. World Patent WO0002448DeBach P (1959) New species and strains of Aphytis (Hymenoptera: Eulophidae) parasitic on the California red scale, Aonidiella aurantii (Mask.), in the Orient. Ann Entomol Soc Am 52:354–362DeBach P, Argyriou L (1967) The colonization and success in Greece of some imported Aphytis spp. (Hymenoptera: Aphelinidae) parasitic on citrus scale insects (Homoptera: Diaspididae). Biocontrol 12:325–342Desneux N, Decourtye A, Delpuech JM (2007) The sublethal effects of pesticides on beneficial arthropods. Ann Rev Entomol 52:81–106Diari Oficial de la Comunitat Valenciana (DOCV) (2008) DOCV no. 5901, 26. Resolution 27 October 2008 of Consellería de Agricultura, Pesca y Alimentación; November 2008. http://www.docv.gva.es/datos/2008/11/26/pdf/2008_13692.pdfDomínguez-Ruiz J, Sanchis J, Navarro-Llopis V, Primo J (2008) A new long-life trimedlure dispenser for Mediterranean fruit fly. J Econ Entomol 101:1325–1330Eliahu M, Blumberg D, Horowitz AR, Ishaaya I (2007) Effect of pyriproxyfen on developing stages and embryogenesis of California red scale (CRS), Aonidiella aurantii. Pest Manag Sci 63:743–746Furness G, Buchanan G, George R, Richardson N (1983) A history of the biological and integrated control of red scale, Aonidiella aurantii on citrus in the lower Murray Valley of Australia. Biocontrol 28:99–212Grafton-Cardwell EE, Gu P (2003) Conserving vedalia beetle, Rodolia cardinalis (Mulsant) (Coleoptera : Coccinellidae), in citrus: a continuing challenge as new insecticides gain registration. J Econ Entomol 96:1388–1398Grafton-Cardwell EE, Reagan CA (1995) Selective use of insecticides for control of armored scale (Homoptera: Diaspididae) in San-Joaquin Valley California citrus. J Econ Entomol 88:1717–1725Grafton-Cardwell EE, Vehrs SLC (1995) Monitoring for organophosphate-resistant and carbamate-resistant armored scale (Homoptera: Diaspididae) in San-Joaquin Valley citrus. J Econ Entomol 88:495–504Grafton-Cardwell EE, Lee JE, Stewart JR, Olsen KD (2006) Role of two insect growth regulators in integrated pest management of citrus scales. J Econ Entomol 99:733–744Grout TG, Richards GI (1991a) Effect of buprofezin applications at different phenological times on California red scale (Homoptera: Diaspididae). J Econ Entomol 84:1802–1805Grout TG, Richards GI (1991b) Value of pheromone traps for predicting infestations of red scale, Aonidiella aurantii (Maskell) (Homoptera: Diaspididae), limited by natural enemy activity and insecticides used to control citrus thrips, Scirtothrips aurantii Faure (Thysanoptera: Thripidae). J Appl Entomol 111:20–27Grout TG, Du Toit WJ, Hofmeyr JH, Richards GI (1989) California red scale (Homoptera: Diaspididae) phenology on citrus in South Africa. J Econ Entomol 82:793–798Hefetz A, Kronengerg S, Peleg BA, Bar-zakay I (1988) Mating disruption of the California red scale Aonidiella aurantii (Homoptera: Diaspididae). In: Proceeding 6th International Citrus Congress, Tel Aviv (Israel), pp 1121–1127Hernández-Penadés P, Rodríguez-Reina JM, García-Marí F (2002) Umbrales de tratamiento para cóccidos diaspídidos en cítricos. Bol San Veg Plagas 28:469–478Hothorn T, Bretz F, Westfall P (2008) Simultaneous Inference in General Parametric Models. Biometrical J 50:346–363Ioratti C, Anfora G, Tasin M, De Cristofaro A, Witzgall P, Lucchi A (2011) Chemical ecology and management of Lobesia botrana (Lepidoptera: Tortricidae). J Econ Entomol 104:1125–1137Kehat M, Anshelevich L, Harel M, Dunkelblum E (1995) Control of the codling moth (Cydia pomonella) in apple and pear orchards in Israel by mating disruption. Phytoparasitica 23:285–296Kennett CE, Hoffmann RW (1985) Seasonal development of the California red scale (Homoptera: Diaspididae) in San Joaquin Valley citrus based on degree-day accumulation. J Econ Entomol 78:73–79Levitin E, Cohen E (1998) The involvement of acetylcholinesterase in resistance of the California red scale shape Aonidiella aurantii to organophosphorus pesticides. Entomol Exp Appl 88:115–121Lykouressis D, Perdikis D, Samartzis D, Fantinou A, Toutouzas S (2005) Management of the pink bollworm Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) by mating disruption in cotton fields. Crop Prot 24:177–183McLaren IW, Buchanan GA (1973) Parasitism by Aphytis chrysomphali Mercet and A. melinus Debach of Californian red scale, Aonidiella aurantii (Maskell), in relation to seasonal availability of suitable stages of the scale. Austr J Zool 21:111–117Moreno DS, Kennett CE (1985) Predictive year-end California red scale (Homoptera: Diaspididae) orange fruit infestations based on catches of males in the San-Joaquin Valley. J Econ Entomol 78:1–9Moreno DS, Luck RF (1992) Augmentative releases of Aphytis melinus (Hymenoptera: Aphelinidae) to suppress California red scale (Homoptera: Diaspididae) in southern California lemon orchards. J Econ Entomol 85:1112–1119Pekas A, Aguilar A, Tena A, García-Marí F (2010) Influence of host size on parasitism by Aphytis chrysomphali and A. melinus (Hymenoptera: Aphelinidae) in Mediterranean populations of California red scale Aonidiella aurantii (Hemiptera: Diaspididae). Biol Control 55:132–140Rill S, Grafton-Cardwell EE, Morse JG (2007) Effects of pyriproxyfen on California red scale (Hemiptera: Diaspididae) development and reproduction. J Econ Entomol 100:1435–1443Rodrigo E, Troncho P, García-Marí F (1996) Parasitoids (Hymenoptera: Aphelinidae) of three scale insects (Homoptera: Diaspididae) in a citrus grove in Valencia, Spain. Entomophaga 41:77–94Roelofs WL, Gieselmann MJ, Cardé AM, Tashiro H, Moreno DS, Henrick CA, Anderson RJ (1977) Sex-pheromone of California red scale, Aonidiella aurantii. Nature 26:698–699Rongai D, Cerato C, Lazzeri L, Palmieri S, Patalano G (2008) Vegetable oil formulation as biopesticide to control California red scale (Aonidiella aurantii Maskell). J Pest Sci 81:179–185Sorribas JJ, Rodríguez R, Rodrigo E, García-Marí F (2008) Niveles de parasitismo y especies de parasitoides del piojo rojo de california Aonidiella aurantii (Hemiptera: Diaspididae) en cítricos de la Comunidad Valenciana. Bol San Veg Plagas 34:201–210Sorribas J, van Baaren J, Garcia-Marí F (2012) Effects of climate on the introduction, distribution and biotic potential of parasitoids: applications to biological control of California red scale. Biol Control 62:103–112Staten RT, Flint HM, Weddle RC, Quintero E, Zarate RE, Finell CM, Hernandes M, Yamamoto A (1987) Pink bollworm (Lepidoptera: Gelechiidae): large-scale field trials with a high-rate gossyplure formulation. J Econ Entomol 80:1267–1271Tashiro H, Chambers DL (1967) Reproduction in the California Red Scale, Aonidiella aurantii (Homoptera: Diaspididae). I. Discovery and extraction of a female sex pheromone. Ann Entomol Soc Am 60:1166–1170Tena A, Llácer E, Urbaneja A (2013) Biological control of a non-honeydew producer mediated by a distinct hierarchy of honeydew quality. Biol Control 67:117–122University of California (1991) Integrated pest management for citrus. University of California, BerkeleyVacas S, Alfaro C, Navarro-Llopis V, Primo J (2009) The first account of the mating disruption technique for the control of California red scale Aonidiella aurantii Maskell (Homoptera: Diaspididae) using new biodegradable dispensers. Bull Entomol Res 99:415–423Vacas S, Alfaro C, Navarro-Llopis V, Primo J (2010) Mating disruption of California red scale, Aonidiella aurantii Maskell (Homoptera: Diaspididae), using biodegradable mesoporous pheromone dispensers. Pest Manag Sci 66:745–751Vacas S, Vanaclocha P, Alfaro C, Primo J, Verdú MJ, Urbaneja A, Navarro-Llopis V (2011) Mating disruption for the control of Aonidiella aurantii Maskell (Hemiptera: Diaspididae) may contribute to increased effectiveness of natural enemies. Pest Manag Sci 68:142–148Vanaclocha P, Vacas S, Alfaro C, Primo J, Verdú MJ, Navarro-Llopis V, Urbaneja A (2012) Life history parameters and scale-cover surface area of Aonidiella aurantii are altered in a mating disruption environment: implications for biological control. Pest Manag Sci 68:1092–1097Vanaclocha P, Vidal-Quist C, Oheix S, Montón H, Planes L, Catalán J, Tena A, Verdú MJ, Urbaneja A (2013) Acute toxicity in laboratory tests of fresh and aged residues of pesticides used in citrus on the parasitoid Aphytis melinus. J Pest Sci 86:329–336Yarom I, Blumberg D, Ishaaya I (1988) Effects of buprofezin on California red scale (Homoptera: Diaspididae) and Mediterranean black scale (Homoptera: Coccidae). J Econ Entomol 81:1581–1585Yust HR, Nelson HD, Busbey RL (1943) Comparative susceptibility of two strains of California red scale to HCN, with special reference to the inheritance of resistance. J Econ Entomol 36:744–74

    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

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    A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

    Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

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    The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30
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