467 research outputs found

    Avaliação do efeito do corte horizontal da copa, com máquina de podar de discos, em pomares de pera “Rocha

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    Current pear pruning making use of pneumatic shears still is a very labour intensive operation. The Proder project “Avaliação da poda mecñnica em pomares de pera” was designed to contribute to solutions that would reduce the present dependence in labour and therefore to promote a reduction in pruning costs. This paper shows the results of a trial made to evaluate the influence of mechanical topping in manual pruning complement field work and pear yield. Topping was performed using a Reynolds 6DT 3.0m cutting bar with six hydraulic-driven circular disc-saws mounted in the three point tractor linkage system. The field trial was performed in a commercial orchard with 20 years, planted in an array of 4m x 2m with tree lines oriented in North-South direction. Trees were trained as the central leader system. In this trial, in a randomised complete block design with four replications, two treatments are being compared leading to 8 plots with one line of 14 trees per plot. The treatments tests were: T1 - manual pruning performed by workers using pneumatic shears, in each year; T2 - Topping the canopy parallel to the ground, using a discs-saw pruning machine mounted in a front loader of an agricultural tractor, followed by manual pruning complement performed by workers with pneumatic shears. Tree height and width was measured, before and after pruning. Work was timed and pear yields evaluated. Mechanical topping seems to be effective in the control of tree height, which can contribute to increase 14% of work rates on manual pruning complement. No significant differences in pear yield were found between treatments

    Measurements of production cross sections of the Higgs boson in the four-lepton final state in proton–proton collisions at S\sqrt{S} = 13 TeV

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    Production cross sections of the Higgs boson are measured in the H -> ZZ -> 4l (l = e, mu) decay channel. A data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS detector at the LHC and corresponding to an integrated luminosity of 137 fb(-1) is used. The signal strength modifier mu, defined as the ratio of the Higgs boson production rate in the 4l channel to the standard model (SM) expectation, is measured to be mu = 0.94 +/- 0.07 (stat)(-0.08)(+0.09) (syst) at a fixed value of m(H) = 125.38 GeV. The signal strength modifiers for the individual Higgs boson production modes are also reported. The inclusive fiducial cross section for the H -> 4l process is measured to be 2.84(-0.22)(+0.23) (stat)(-0.21)(+0.26) (syst) fb, which is compatible with the SM prediction of 2.84 +/- 0.15 fb for the same fiducial region. Differential cross sections as a function of the transverse momentum and rapidity of the Higgs boson, the number of associated jets, and the transverse momentum of the leading associated jet are measured. A new set of cross section measurements in mutually exclusive categories targeted to identify production mechanisms and kinematical features of the events is presented. The results are in agreement with the SM predictions

    Modeling Of Concepts And Mathematical Processes By Petri Nets: The Case Of Integrability Of Real Functions [modelagem De Conceitos E Processos Matemåticos Por Redes De Petri Coloridas: O Caso Da Integrabilidade De FunçÔes Reais]

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    Petri Nets (PNs) are a mathematical and graphical tool for general use. In this paper, the use of PNs is promoted as a modeling tool to organize the teaching of mathematical notions. The modeling presented in this work relies on the strong mathematical basis of PNs. As a case study, a model is constructed for teaching integrability of real functions, based on the evolution of the integral concept. With this aim, it is considered a real bounded function, defined on a closed and bounded interval, that is analyzed according to conditions which ensure or exclude its integration by Cauchy, by Riemann, by Lebesgue or by none of these integrals. The idea of modeling integrals using PN was originated in the context of mathematical classes, as the integral was being taught to first year engineering students.27457595Aalst, W., The application of Petri nets to workflow management (1998) The Journal of Circuits, Systems and Computers, 8 (1), pp. 1-53. , LondonArtigue, M., IngĂ©nierie Didactique (1989) Recherches en Didactique des MathĂ©matiques, 9 (3), pp. 281-308. , ParisBachelard, G., (1999) Le Nouvel Sprit Scientifique, , 6. ed. Paris: Quadrige/PUFBarroso, N., (2009) Um Modelo de Ensino Dos Conceitos de CĂĄlculo Para Os Cursos de Engenharia Fundamentado em Uma Epistemologia HistĂłrica e Baseado Na Metodologia da Engenharia DidĂĄtica: Validação Por Meio Do Conceito de Integral, p. 187. , Tese (Doutorado em Engenharia de TeleinformĂĄtica) - Universidade Federal do CearĂĄ, Fortaleza, 2009Barroso, N., Soares, J.M., Mota, J.C.M., Neto, H.B., Uma SeqĂŒĂȘncia de Ensino para a Introdução do Conceito de Integral de Riemann (2007) ENCONTRO NACIONAL de EDUCAÇÃO MATEMÁTICA, pp. 1-17. , http://www.sbem.com.br/files/ix_enem/Html/comunicacaoCientifica.html, 9., 2007, Belo Horizonte. Anais... Belo Horizonte: Sociedade Brasileira de Educação MatemĂĄtica (SBEM), Acesso em: 21 mar. 2013Brousseau, G., Fondements et mĂ©thodes de la Didactique des MathĂ©matiques (1986) Recherches en Didactique des Matematiques, 7 (2), pp. 33-116. , ParisChen, J., Smith, S., Cardinality of the set of real functions with a given continuity set (2008) Pi Mu Epsilon Journal, Worcester, 12 (8), pp. 449-454. , http://www.sju.edu/~smith/Current_Courses/continuitysetsrev.pdf, Massachusetts, Acesso em: 21 mar. 2013Dahan-Dalmedico, A., Peiffer, J., (1986) Une Histoire des MathĂ©matiques: Routes et DĂ©dales, , Paris: Le SeuilD'Amore, B., (2005) Epistemologia e DidĂĄtica da MatemĂĄtica, , SĂŁo Paulo: EscriturasFinney, R., Weir, M., Giordano, F., (2004) CĂĄlculo George B. Thomas, 1. , 10. ed. SĂŁo Paulo: Pearson-Addison WesleyJensen, K., Coloured petri nets (1997) Basic Concepts, Analysis Methods and Practical Use, 1. , 2. ed. Berlin: Springer-VerlagLeithold, L., (1994) CĂĄlculo Com Geometria AnalĂ­tica, , 3. ed. SĂŁo Paulo: HarbraMoreira, M., (1999) Teorias da Aprendizagem, , SĂŁo Paulo: EPUNovak, J.D., Cañas, A.J., Theoretical origins of concept maps, how to contruct them, and uses in education (2007) Refleting Education, 3 (1), pp. 29-42. , Londres, NovPĂĄdua, S., Silva, A., Porto, A., Inamasu, R., O potencial das redes de Petri em modelagem e anĂĄlise de processos de negĂłcios (2004) GestĂŁo & Produção, 11 (1), pp. 109-119. , SĂŁo Carlos, jan./abrPais, L.C., (2001) DidĂĄtica da MatemĂĄtica: Uma AnĂĄlise da InfluĂȘncia Francesa, , 2. ed. Belo Horizonte: AutĂȘntica, (Coleção TendĂȘncias em Educação MatemĂĄtica)Park, S., Kim, Y., Applying petri nets to model customized learning and cooperative learning with competence (2008) International Journal of Computer Science and Network Security, 8 (2), pp. 127-132. , Seul, FebPeterson, J.L., (1981) Petri Net Theory and the Modeling of Systems, , New Jersey: Prentice HallPontes, J., Silva, J., Teoria da Aprendizagem Significativa de David Ausubel: Perguntas e Respostas (2006) SĂ©rie-Estudos: PeriĂłdicos Do Mestrado em Educação da UCDB, 21, pp. 117-130. , Campo Grande, jan./junRoyden, H., (1971) Real Analysis, , 3. ed. New Jersey: Prentice HallRudin, W., (1976) Principles of Mathematical Analysis, , 3.ed. New York: McGraw-HillRussel, B., (2007) Introdução À Filosofia MatemĂĄtica, , 1. ed. Rio de Janeiro: ZaharSingh, S., (1999) O Último Teorema de Fermat, , 5. ed. Rio de Janeiro: RecordStewart, I., (2004) Galois Theory, , 3. ed. FlĂłrida: Chapman & Hall/CR

    Genetic studies of body mass index yield new insights for obesity biology

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    Note: A full list of authors and affiliations appears at the end of the article. Obesity is heritable and predisposes to many diseases. To understand the genetic basis of obesity better, here we conduct a genome-wide association study and Metabochip meta-analysis of body mass index (BMI), a measure commonly used to define obesity and assess adiposity, in up to 339,224 individuals. This analysis identifies 97 BMI-associated loci (P 20% of BMI variation. Pathway analyses provide strong support for a role of the central nervous system in obesity susceptibility and implicate new genes and pathways, including those related to synaptic function, glutamate signalling, insulin secretion/action, energy metabolism, lipid biology and adipogenesis.</p

    Euclid. I. Overview of the Euclid mission

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    The current standard model of cosmology successfully describes a variety of measurements, but the nature of its main ingredients, dark matter and dark energy, remains unknown. Euclid is a medium-class mission in the Cosmic Vision 2015-2025 programme of the European Space Agency (ESA) that will provide high-resolution optical imaging, as well as near-infrared imaging and spectroscopy, over about 14,000 deg^2 of extragalactic sky. In addition to accurate weak lensing and clustering measurements that probe structure formation over half of the age of the Universe, its primary probes for cosmology, these exquisite data will enable a wide range of science. This paper provides a high-level overview of the mission, summarising the survey characteristics, the various data-processing steps, and data products. We also highlight the main science objectives and expected performance

    Euclid. I. Overview of the Euclid mission

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    International audienceThe current standard model of cosmology successfully describes a variety of measurements, but the nature of its main ingredients, dark matter and dark energy, remains unknown. Euclid is a medium-class mission in the Cosmic Vision 2015-2025 programme of the European Space Agency (ESA) that will provide high-resolution optical imaging, as well as near-infrared imaging and spectroscopy, over about 14,000 deg^2 of extragalactic sky. In addition to accurate weak lensing and clustering measurements that probe structure formation over half of the age of the Universe, its primary probes for cosmology, these exquisite data will enable a wide range of science. This paper provides a high-level overview of the mission, summarising the survey characteristics, the various data-processing steps, and data products. We also highlight the main science objectives and expected performance

    Search for new Higgs bosons via same-sign top quark pair production in association with a jet in proton-proton collisions at s=13TeV

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    A search is presented for new Higgs bosons in proton-proton (pp) collision events in which a same-sign top quark pair is produced in association with a jet, via the pp→tH/A→ttc‟ and pp→tH/A→ttu‟ processes. Here, H and A represent the extra scalar and pseudoscalar boson, respectively, of the second Higgs doublet in the generalized two-Higgs-doublet model (g2HDM). The search is based on pp collision data collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 138fb−1. Final states with a same-sign lepton pair in association with jets and missing transverse momentum are considered. New Higgs bosons in the 200–1000 GeV mass range and new Yukawa couplings between 0.1 and 1.0 are targeted in the search, for scenarios in which either H or A appear alone, or in which they coexist and interfere. No significant excess above the standard model prediction is observed. Exclusion limits are derived in the context of the g2HDM

    Measurement of the ttÂŻ charge asymmetry in events with highly Lorentz-boosted top quarks in pp collisions at s=13 TeV

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    The measurement of the charge asymmetry in top quark pair events with highly Lorentz-boosted top quarks decaying to a single lepton and jets is presented. The analysis is performed using proton-proton collisions at s=13TeV with the CMS detector at the LHC and corresponding to an integrated luminosity of 138 fb−1. The selection is optimized for top quarks produced with large Lorentz boosts, resulting in nonisolated leptons and overlapping jets. The top quark charge asymmetry is measured for events with a tt¯ invariant mass larger than 750 GeV and corrected for detector and acceptance effects using a binned maximum likelihood fit. The measured top quark charge asymmetry of (0.42−0.69+0.64)% is in good agreement with the standard model prediction at next-to-next-to-leading order in quantum chromodynamic perturbation theory with next-to-leading-order electroweak corrections. The result is also presented for two invariant mass ranges, 750–900 and >900GeV

    Search for new heavy resonances decaying to WW, WZ, ZZ, WH, or ZH boson pairs in the all-jets final state in proton-proton collisions at s=13TeV

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    A search for new heavy resonances decaying to WW, WZ, ZZ, WH, or ZH boson pairs in the all-jets final state is presented. The analysis is based on proton-proton collision data recorded by the CMS detector in 2016–2018 at a centre-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 138fb−1. The search is sensitive to resonances with masses between 1.3 and 6TeV, decaying to bosons that are highly Lorentz-boosted such that each of the bosons forms a single large-radius jet. Machine learning techniques are employed to identify such jets. No significant excess over the estimated standard model background is observed. A maximum local significance of 3.6 standard deviations, corresponding to a global significance of 2.3 standard deviations, is observed at masses of 2.1 and 2.9 TeV. In a heavy vector triplet model, spin-1 Zâ€Č and Wâ€Č resonances with masses below 4.8TeV are excluded at the 95% confidence level (CL). These limits are the most stringent to date. In a bulk graviton model, spin-2 gravitons and spin-0 radions with masses below 1.4 and 2.7TeV, respectively, are excluded at 95% CL. Production of heavy resonances through vector boson fusion is constrained with upper cross section limits at 95% CL as low as 0.1fb
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