39 research outputs found

    Accuracy versus precision in boosted top tagging with the ATLAS detector

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    Abstract The identification of top quark decays where the top quark has a large momentum transverse to the beam axis, known as top tagging, is a crucial component in many measurements of Standard Model processes and searches for beyond the Standard Model physics at the Large Hadron Collider. Machine learning techniques have improved the performance of top tagging algorithms, but the size of the systematic uncertainties for all proposed algorithms has not been systematically studied. This paper presents the performance of several machine learning based top tagging algorithms on a dataset constructed from simulated proton-proton collision events measured with the ATLAS detector at √ s = 13 TeV. The systematic uncertainties associated with these algorithms are estimated through an approximate procedure that is not meant to be used in a physics analysis, but is appropriate for the level of precision required for this study. The most performant algorithms are found to have the largest uncertainties, motivating the development of methods to reduce these uncertainties without compromising performance. To enable such efforts in the wider scientific community, the datasets used in this paper are made publicly available.</jats:p

    Haemophilus influenzae porine ompP2 gene transfer mediated by graphene oxide nanoparticles with effects on transformation process and virulence bacterial capacity

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    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Background: H. influenzae is a natural competent bacterium that can uptake DNA from the environment and recombine into bacterial genome. The outbreaks of Brazilian purpuric fever, heavily polluted areas of a different H. influenzae biogroup - aegyptius - as well as gene transference between Neisseria meningitis make the transformation process an important evolutionary factor. This work studied the horizontal transference of the ompP2 gene from a multiresistant strain of H. influenzae 07 (NTHi), under the influence of graphene oxide nanoparticles in order to mimic an atmosphere rich in suspended particles and this way verify if the CFU transformants number was increased. Material and methods: In this article the gene ompP2 was transformed into different strains of H. influenzae mediated or not by graphene oxide nanoparticles in suspension, followed by the adhesion tests in Hec-1B (human endometrium adenocarcinoma) and A549 (pulmonary epithelial carcinoma) cells lines. The transformation frequency and the adhesion capacity were determined in all the mutants to which the ompP2 gene was transferred and compared to their wild type strains. Results: The nanoparticles increased the transformation ratio of one particular strain isolated from a pneumonia case. The adhesion patterns to A549 and Hec1b cell lines of these mutated bacteria has their capacity increased when compared to the wild type. Conclusions: Graphene oxide nanoparticles aid the transformation process, helping to increase the number of CFUs, and the mutants generated with the ompP2 gene from a H. influenzae resistant strain not only present a chloramphenicol resistance but also have an increased adherence patterns in A549 and Hec1B cell lines.12Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)FAPESP [2011/14079-2, 2011/21685-6, 2012/15046-3

    Estudo sobre a fluorose dentária num município do sul do Brasil Study on the dental fluorosis in a Southern city of Brazil

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    O objetivo deste estudo foi determinar a frequência e a severidade da fluorose dentária, bem como verificar possíveis associações com cárie dentária, sexo, idade, etnia e localização geográfica das escolas, nos escolares de doze e de quinze a dezenove anos de idade do município de Passo Fundo, Rio Grande do Sul. A população estudada foi constituída por 633 escolares, de ambos os sexos, matriculados em vinte e seis escolas municipais de ensino fundamental, nas idades índices citadas. Os exames foram realizados por três examinadores previamente calibrados para a aplicação do Índice de Dean. A prevalência de fluorose dentária no grupo estudado foi de 32,8%. O grau predominante foi o muito leve (78,4%), seguido pelos graus leve (11,1%), questionável (8,7%) e moderado (1,9%). A prevalência de fluorose dentária na população estudada foi expressiva, embora com um baixo grau de severidade. Os fatores idade e índice de cárie dentária mostraram-se relacionados à variável resposta.<br>The objective of this article is to determine the frequency and severity of dental fluorosis, as well as to verify possible associations with dental caries, gender, age, ethnicity and geographic location of schools in schoolchildren of 12 years old and from 15 to 19 years in the city of Passo Fundo, Rio Grande do Sul State, Brazil. A total of 633 schoolchildren of both genders at the cited ages, enrolled in 26 public schools of fundamental teaching were involved in the epidemiological study. The inspection was performed by three examiners previously trained to apply Dean's Index. The prevalence of dental fluorosis in the studied group was of 32.8%. Predominant degree was the very light (78.4%), followed by light (11.1%), questionable (8.7%) and moderate (1.9%). The prevalence of dental fluorosis was expressive in this population, however, with a low degree of severity. Factors such as age and dental caries index showed to be related to the variable response
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