4,075 research outputs found

    Using discrete Ricci curvatures to infer COVID-19 epidemic network fragility and systemic risk

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    The damage of the novel Coronavirus disease (COVID-19) is reaching unprecedented scales. There are numerous classical epidemiology models trying to quantify epidemiology metrics. Usually, to forecast epidemics, classical approaches need parameter estimations, such as the contagion rate or the basic reproduction number. Here, we propose a data-driven, parameter-free, geometric approach to access the emergence of a pandemic state by studying the Forman-Ricci and Ollivier- Ricci network curvatures. Discrete Ollivier-Ricci curvature has been used successfully to forecast risk in nancial networks and we suggest that those results can provide analogous results for COVID-19 epidemic time-series. We rst compute both curvatures in a toy-model of epidemic time-series with delays, which allows us to create epidemic networks. We also compared our results to classical network metrics. By doing so, we are able to verify that the Ollivier-Ricci and Forman-Ricci curvatures can be a parameter-free estimate for identifying a pandemic state in the simulated epidemic. On this basis, we then compute both Forman-Ricci and Ollivier-Ricci curvatures for real epidemic networks built from COVID-19 epidemic time-series available at the World Health Organization (WHO). This approach allow us to detect early warning signs of the emergence of the pandemic. The advantage of our method lies in providing an early geometrical data marker for the pandemic state, regardless of parameter estimation and stochastic modelling. This work opens the possibility of using discrete geometry to study epidemic networks. Keywords: COVID-19, SARS2, Forman-Ricci Curvature, Ollivier-Ricci curvature, Epidemiology, Topologi- cal Data Analysi

    Viabilidade econômica da produção de eucalipto no polo moveleiro de Marco - Ceará.

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    Made available in DSpace on 2018-01-18T22:14:39Z (GMT). No. of bitstreams: 1 ART17075.pdf: 565213 bytes, checksum: 9f477d0d7a05c8470ae17f01aa8fb75f (MD5) Previous issue date: 2018-01-15bitstream/item/171362/1/ART17075.pd

    Climatic Aptitude Evaluation for Grapevine Cultivation in Pão de Açúcar, Alagoas

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    The grapes production in Brazil is comprised in southeastern and southern regions and also in the semi-arid Pernambuco. Environmental, climatic and even human factors influence on quality of grape production, which are sensitive to weather changes. In Alagoas State, a pilot project was carried out for Municipalities of Rio Largo, Pão de Açúcar and Delmiro Gouveia between 2013 to 2015 years; but the results were incipient. This work evaluated the climatic aptitude for grapevine cultivation for municipality of Pão de Açúcar. For climate characterization, three indices of the Geoviticure Multicriteria Climatic Classification System (MCC) were adopted: Heliothermic (HI), Cold Night (CI) and Dryness (DI), considering different cycles during the year. The Zuluaga Index (IZ) was also used to evaluate the risk of incidence of fungal diseases of the vine, especially in relation at mildew incidence (Plasmoparaviticola), a major disease in humid regions. According on CI, DI and ZI indices, the municipality of Pão de Açúcar presented climatic aptitude for vines production with highest quality potential between August to January months, classified as preferential for all indexes analyzed

    Germinação de sementes e tipos de explante na propagação in vitro da Pitaya vermelha (Hylocereus polyrhizus).

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    Melocactus.

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    As cactáceas destacam-se como plantas ornamentais, forrageiras, alimentícias, paisagísticas, medicinais e como matéria-prima na fabricação de produtos de higiene e cosméticos. O Brasil é considerado o maior centro de diversidade de Melocactus do mundo, cujas espécies são conhecidas como coroa-de-frade.bitstream/item/173179/1/DOC18001.pd

    Characterization of Mesocriconema species associated to Grapevine Decline Disease in Southern Brazil.

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    The grapevine decline disease (GDD) is a complex disease that causes substantial losses in grape production. Ring nematode (Mesocriconema xenoplax) is frequently detected in symptomatic vineyards. Unfortunately, this nematode is frequently mis-identifed due to its similarities with other species of this genus. In this study, the hypothesis was tested that there is a species complex of Mesocriconema associated with GDD in southern Brazil. This hypothesis was based on a previous result that identifed diferent Mesocriconema species in vineyards in southern Brazil including M. xenoplax, M. curvatum, M. rusticum, M. sphaerocephalum, M. ornatum, and another seven undefned species, using only morphometric data. This current study provides the frst characterization of Mesocriconema species associated with GDD, their distribution, and variability, through the use of morphological and molecular analysis in an integrative approach.Online First

    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

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

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    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal
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