138 research outputs found

    Análise de desempenho acadêmico nas disciplinas probabilidade e estatística, estatística aplicada e bioestatística

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    Trabalho de Conclusão de Curso (graduação)—Universidade de Brasília, Departamento de Estatística, Estágio Supervisionado II, 2011.Neste Presente Trabalho foi estudado o desempenho dos alunos da Universidade de Brasília (Campus Darcy Ribeiro) nas seguintes disciplinas ofertadas pelo Departamento de Estatística para os diferentes cursos como: Estatística aplicada, Bioestatísticas ou Probabilidade e Estatística. O intuito deste estudo é identificar características associadas à reprovação nestas disciplinas com base no banco de dados extraído do Sistema de Informação de Graduação. Utilizando modelagem via regressão logística observou-se algumas características comuns na reprovação dos alunos em todas as disciplinas, como: “Sexo”, “Professor”, “Curso” “Período que cursou a disciplina” e “Período que ingressou na UnB”. Outras características foram particulares a cada disciplina, como “nacionalidade” a Estatística Aplicada, e se o aluno “fez a disciplina no fluxo” para Bioestatística e Probabilidade e Estatística

    Long-Term Correlations and Cross-Correlations in Meteorological Variables and Air Pollution in a Coastal Urban Region

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    In this work, we evaluated the evolution of some atmospheric pollutants (O3, NOx and PM10) over time and their relationship with four different climate variables (solar irradiation, air temperature, relative humidity and wind speed). To this end, we assessed the long-range dependence of those concentrations with a Detrended Fluctuation Analysis (DFA) and analyzed the cross-correlation of such dependence with the climate variables through a Detrended Cross-Correlation Coefficient Analysis (ρDCCA). The results show that air pollution tends to increase over time, impairing air quality and likely affecting human health. The results indicate a cross-correlation between air pollution and the climatic variables, which persisted for a certain period, with a greater correlation between O3 concentration and wind, mainly temperature, and a negative correlation with humidity for all monitoring stations. Moreover, unlike O3 and PM10, NOx concentrations always had a persistent behavior in the region of study for the entire analyzed period.N/

    Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV

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    The t t-bar production cross section (sigma[t t-bar]) is measured in proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS experiment, corresponding to an integrated luminosity of 2.3 inverse femtobarns. The measurement is performed in events with two leptons (electrons or muons) in the final state, at least two jets identified as jets originating from b quarks, and the presence of an imbalance in transverse momentum. The measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/- 2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction of the standard model.Comment: Replaced with published version. Included journal reference and DO

    Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics

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    A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN

    The control and prevention of COVID-19 transmission in children : a protocol for systematic review and meta-analysis

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    Background: The pandemic following the rapid spread of the new SARS-CoV-2 virus has hit all continents and caused thousands of deaths worldwide. Evidence has been published on epidemiological and clinical characteristics of population groups considered at risk; however, information for the other population groups, especially for the child population, is needed. In this context, this protocol describes a systematic review that will aim to identify the evidence on control and prevention of COVID-19 transmission among children and adolescents, as well as to describe the epidemiological profile and clinical and immunological characteristics of COVID-19 in this population. Methods: This protocol will be developed in accordance with PRISMA-P. The searches will be conducted in PubMed, Web of Science, ScienceDirect, EMBASE, and Scopus, seeking clinical trials. Observational studies and case reports with Children and adolescents (≤19 years) infected with SARS-CoV-2 will be included whether they report information on the control of prevention and COVID-19 transmission. Two independent researchers will perform the selection of articles, removal of duplication, and screening by Rayyan QCRI application. Cochrane's RoB 2.0, ROBINS-I, and CASP tools will be used to assess the risk of bias. Meta-analysis, subgroup analyses, and/or descriptive analyses will be carried out based on the data conditions included. Results: A high-quality synthesis of the available evidences on the epidemiological profile, the clinical and immunological characteristics involved in children, and adolescents diagnosed with COVID-19, as well as the participation of this population in the transmission dynamics of SARS-CoV-2 will be provided. Conclusion: This systematic review has an important relevance in the current context because it has a great potential to help the development of new control and prevention strategies in the pediatric population

    The Consumption of Wild Edible Plants

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    Wild edible plants are of great importance in both former and current human societies. Their use embodies evolutionary trends, continuing interactions between men and nature, relevant traditional knowledge, and cultural heritage. A conceptual approach to wild edible plants, including the contribution of such species to people's diets and daily lives, focusing on nutritional and cultural value, food sovereignty and security, as well as the huge legacy for future generations, leads to a general overview of new tendencies and availability of wild plant resources according to geographic regions. The potential benefits and the continual need for conservation strategies of plants, habitats, and associated knowledge are also discussed, enhancing biodiversity and biocultural patrimony. Finally, some examples of culturally significant edible wild plants are described, emphasizing the importance of knowledge transmission and sustainable uses in a changing world.info:eu-repo/semantics/publishedVersio

    Atomic spectrometry update – a review of advances in environmental analysis

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    A historical overview of the classification, evolution, and dispersion of Leishmania parasites and sandflies

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    Background The aim of this study is to describe the major evolutionary historical events among Leishmania, sandflies, and the associated animal reservoirs in detail, in accordance with the geographical evolution of the Earth, which has not been previously discussed on a large scale. Methodology and Principal Findings Leishmania and sandfly classification has always been a controversial matter, and the increasing number of species currently described further complicates this issue. Despite several hypotheses on the origin, evolution, and distribution of Leishmania and sandflies in the Old and New World, no consistent agreement exists regarding dissemination of the actors that play roles in leishmaniasis. For this purpose, we present here three centuries of research on sandflies and Leishmania descriptions, as well as a complete description of Leishmania and sandfly fossils and the emergence date of each Leishmania and sandfly group during different geographical periods, from 550 million years ago until now. We discuss critically the different approaches that were used for Leishmana and sandfly classification and their synonymies, proposing an updated classification for each species of Leishmania and sandfly. We update information on the current distribution and dispersion of different species of Leishmania (53), sandflies (more than 800 at genus or subgenus level), and animal reservoirs in each of the following geographical ecozones: Palearctic, Nearctic, Neotropic, Afrotropical, Oriental, Malagasy, and Australian. We propose an updated list of the potential and proven sandfly vectors for each Leishmania species in the Old and New World. Finally, we address a classical question about digenetic Leishmania evolution: which was the first host, a vertebrate or an invertebrate? Conclusions and Significance We propose an updated view of events that have played important roles in the geographical dispersion of sandflies, in relation to both the Leishmania species they transmit and the animal reservoirs of the parasites
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