83 research outputs found

    Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

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    A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

    Electron identification with the CMS detector and applications for Higgs and W boson searches

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    The efficient identification of high energy electrons at the Large Hadron Collider (LHC) is of primary importance for the study of many physics processes, like the search for the Higgs boson and other Standard Model and beyond Standard Model processes. For the measurement of the electron energy, the CMS exp eriment uses a high precision Electromagnetic Calorimeter (ECAL). It is divided into a barrel and two end-caps composed of lead tungstate crystals, which are read by photo detectors. The integration of the ECAL readout electronics into the structure of the ECAL, the testing strategy, and the current performance of the ECAL electronics are presented in detail. In February 2010, 99.6% of the 75 848 ECAL readout channels were found to be fully operational. The identification of isolated electrons with the CMS detector is discussed, focusing on the reduction of the fake rate, i.e. the rate of jets or photons that are miss-identified as electrons. Tools for the electron selection are introduced, and a simple and effective electron selection for isolated high energy electrons in the ECAL barrel is presented. The study of the electron selection based on Monte Carlo simulations results in a fake rate of only 10−4 and an efficiency to select genuine electrons of 70%. The electron selection is applied to a study of the search of the Higgs boson in the channel Higgs → W+ W− → e+ νe− ν¯ and for a Higgs mass in the range 155-180 GeV. In particular, the background process W± X → e± νX is investigated in detail, where X is a jet or a photon that is miss-identified as an electron. Using the proposed electron selection, this background can be reduced well below the irreducible backgrounds. Finally, the developed electron selection is used in a study of the selection of W± → e± ν events with low background contributions. In addition, a new method to measure the transverse momentum spectrum of the selected W bosons is proposed. The measurement of this spectrum can constrain the gluon distribution functions of the proton at the LHC energies

    Measurement of the charge ratio of atmospheric muons with the CMS detector

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    We present a measurement of the ratio of positive to negative muon fluxes from cosmic ray interactions in the atmosphere, using data collected by the CMS detector both at ground level and in the underground experimental cavern at the CERN LHC. Muons were detected in the momentum range from 5 GeV/c to 1 TeV/c. The surface flux ratio is measured to be 1.2766±0.0032(stat.)±0.0032(syst.), independent of the muon momentum, below 100 GeV/c. This is the most precise measurement to date. At higher momenta the data are consistent with an increase of the charge ratio, in agreement with cosmic ray shower models and compatible with previous measurements by deep-underground experiments.ISSN:0370-2693ISSN:0031-9163ISSN:1873-244

    Transverse-Momentum and Pseudorapidity Distributions of Charged Hadrons in pp Collisions at √s=7 TeV

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    Charged-hadron transverse-momentum and pseudorapidity distributions in proton-proton collisions at √s=7  TeV are measured with the inner tracking system of the CMS detector at the LHC. The charged-hadron yield is obtained by counting the number of reconstructed hits, hit pairs, and fully reconstructed charged-particle tracks. The combination of the three methods gives a charged-particle multiplicity per unit of pseudorapidity dNch/dη||η|<0.5=5.78±0.01(stat)±0.23(syst) for non-single-diffractive events, higher than predicted by commonly used models. The relative increase in charged-particle multiplicity from √s=0.9 to 7 TeV is [66.1±1.0(stat)±4.2(syst)]%. The mean transverse momentum is measured to be 0.545±0.005(stat)±0.015(syst)  GeV/c. The results are compared with similar measurements at lower energies

    Measurement of the underlying event activity at the LHC with √s=7 TeV and comparison with √s=0.9 TeV

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    A measurement of the underlying activity in events with a jet of transverse momentum in the several GeV region is performed in proton-proton collisions at √s=0.9 and 7 TeV, using data collected by the CMS experiment at the LHC. The production of charged particles with pseudorapidity |η|  0.5 GeV/c is studied in the azimuthal region transverse to that of the leading set of charged particles forming a track-jet. A significant growth of the average multiplicity and scalar-pT sum of the particles in the transverse region is observed with increasing pT of the leading track-jet, followed by a much slower rise above a few GeV/c. For track-jet pT larger than a few GeV/c, the activity in the transverse region is approximately doubled with a centre-of-mass energy increase from 0.9 to 7 TeV. Predictions of several QCD-inspired models as implemented in pythia are compared to the data.ISSN:1126-6708ISSN:1029-847

    Measurement of the Inclusive Jet Cross Section in pp Collisions at √s=7  TeV

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    The inclusive jet cross section is measured in pp collisions with a center-of-mass energy of 7 TeV at the Large Hadron Collider using the CMS experiment. The data sample corresponds to an integrated luminosity of 34  pb−1. The measurement is made for jet transverse momenta in the range 18–1100 GeV and for absolute values of rapidity less than 3. The measured cross section extends to the highest values of jet pT ever observed and, within the experimental and theoretical uncertainties, is generally in agreement with next-to-leading-order perturbative QCD predictions.ISSN:0031-9007ISSN:1079-711
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