186 research outputs found

    Modernity and teacher formation: the 'multiplicadores' practice of the Northeast Educational Technologic Group for informatics applied to education

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    Este trabalho analisa a prática dos multiplicadores dos Núcleos de Tecnologia Educacional (NTEs) do Nordeste na formação de professores para trabalharem com informática na educação. O objetivo é verificar como esta prática se relaciona com a modernidade e como quer ser uma resposta aos desafios da atualidade para o campo educacional no que diz respeito à formação de professores. O aporte teórico utilizado sustenta que a sociedade está permeada de tecnologias, caracterizando esta etapa atual da modernidade e mesmo conformando o seu desenvolvimento, denominado às vezes de sociedade da informação, sociedade do conhecimento e mesmo pós-modernidade. A hipótese principal é que os multiplicadores trabalham com a perspectiva de que o uso da informática na educação caracteriza a modernidade na educação, como parte essencial de um novo paradigma pedagógico. Para o desenvolvimento desta pesquisa foi utilizada uma metodologia etnográfica a fim de possibilitar o conhecimento da realidade a partir da sua vivência cotidiana. Neste sentido, foram observadas as atividades desenvolvidas pelos multiplicadores e também realizadas entrevistas em profundidade para conhecer a percepção que estes atores têm de sua prática. Os dados coletados e analisados apontam para um quadro complexo e mesmo contraditório, característico tanto da etapa atual da modernidade como do próprio processo vivido pelos multiplicadores.This research analyses the multiplicadores" practice of the Northeast Núcleo de Tecnologia Educacional" (Educational Technologic Group), who works with in-service teacher formation for informatics applied to education. This research objective is to verify the relationship between this type of teacher formation and the modernitys concept. More then that, we intend to study how it responds to educational needs referred to teacher formation. The theoretical-base assumes that modern society has been permeated with technology, characterizing modernity as Information Society, Knowledge Society or Post-modernity. The central hypothesis is based on the idea that multiplicadores associate informatics applied to education as educational modernity, and that builds new educational paradigms main part. The ethnography methodology used understanding of researchs problem through every day teachers practice. To do so, we observed teachers activities and carried out interviews about teachers every day classroom work., in order to comprehend teachers perceptions about their practice. The result showed a complex and contradictory situation, characterized by the actual modernity phase and multiplicadores" own identitys process

    Multiplicity dependence of charged-particle intra-jet properties in pp collisions at s\sqrt{s} = 13 TeV

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    International audienceThe first measurement of the multiplicity dependence of intra-jet properties of leading charged-particle jets in proton-proton (pp) collisions is reported. The mean charged-particle multiplicity and jet fragmentation distributions are measured in minimum-bias and high-multiplicity pp collisions at s\sqrt{s} = 13 TeV using the ALICE detector. Jets are reconstructed from charged particles produced in the midrapidity region (η<0.9|\eta| < 0.9) using the sequential recombination anti-kTk_{\rm T} algorithm with jet resolution parameters RR = 0.2, 0.3, and 0.4 for the transverse momentum (pTp_{\rm T}) interval 5-110 GeV/cc. High-multiplicity events are selected by the forward V0 scintillator detectors. The mean charged-particle multiplicity inside the leading jet cone rises monotonically with increasing jet pTp_{\rm T} in qualitative agreement with previous measurements at lower energies. The distributions of jet fragmentation functions zchz^{\rm ch} and ξch\xi^{\rm ch} are measured for different jet-pTp_{\rm T} intervals. Jet-pTp_{\rm T} independent fragmentation of leading jets is observed for wider jets except at high- and low-zchz^{\rm ch}. The observed "hump-backed plateau" structure in the ξch\xi^{\rm ch} distribution indicates suppression of low-pTp_{\rm T} particles. In high-multiplicity events, an enhancement of the fragmentation probability of low-zchz^{\rm ch} particles accompanied by a suppression of high-zchz^{\rm ch} particles is observed compared to minimum-bias events. This behavior becomes more prominent for low-pTp_{\rm T} jets with larger jet radius. The results are compared with predictions of QCD-inspired event generators, PYTHIA 8 with Monash 2013 tune and EPOS LHC. It is found that PYTHIA 8 qualitatively reproduces the jet modification in high-multiplicity events except at high jet pTp_{\rm T}. These measurements provide important constraints to models of jet fragmentation

    Exclusive four pion photoproduction in ultraperipheral Pb-Pb collisions at sNN=5.02\sqrt{s_{\rm NN}} = 5.02 TeV

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    International audienceThe intense photon fluxes from relativistic nuclei provide an opportunity to study photonuclear interactions in ultraperipheral collisions. The measurement of coherently photoproduced π+ππ+π\pi^+\pi^-\pi^+\pi^- final states in ultraperipheral Pb-Pb collisions at sNN=5.02\sqrt{s_{\mathrm{NN}}}=5.02 TeV is presented for the first time. The cross section, dσ\sigma/dyy, times the branching ratio (ρπ+π+ππ\rho\rightarrow \pi^+ \pi^+ \pi^- \pi^-) is found to be 47.8±2.3 (stat.)±7.7 (syst.)47.8\pm2.3~\rm{(stat.)}\pm7.7~\rm{(syst.)} mb in the rapidity interval y<0.5|y| < 0.5. The invariant mass distribution is not well described with a single Breit-Wigner resonance. The production of two interfering resonances, ρ(1450)\rho(1450) and ρ(1700)\rho(1700), provides a good description of the data. The values of the masses (mm) and widths (Γ\Gamma) of the resonances extracted from the fit are m1=1385±14 (stat.)±3 (syst.)m_{1}=1385\pm14~\rm{(stat.)}\pm3~\rm{(syst.)} MeV/c2c^2, Γ1=431±36 (stat.)±82 (syst.)\Gamma_{1}=431\pm36~\rm{(stat.)}\pm82~\rm{(syst.)} MeV/c2c^2, m2=1663±13 (stat.)±22 (syst.)m_{2}=1663\pm13~\rm{(stat.)}\pm22~\rm{(syst.)} MeV/c2c^2 and Γ2=357±31 (stat.)±49 (syst.)\Gamma_{2}=357 \pm31~\rm{(stat.)}\pm49~\rm{(syst.)} MeV/c2c^2, respectively. The measured cross sections times the branching ratios are compared to recent theoretical predictions

    Measurement of Λ3H{}_{\Lambda}^{3}\mathrm{H} production in Pb-Pb collisions at sNN\sqrt{s_{\mathrm{NN}}} = 5.02 TeV

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    International audienceThe first measurement of Λ3H_{\Lambda}^{3}\mathrm{H} and Λ3H^3_ {\overline{\Lambda}}\overline{\mathrm{H}} differential production with respect to transverse momentum and centrality in Pb-Pb collisions at sNN=5.02\sqrt{s_{\mathrm{NN}}}=5.02~TeV is presented. The Λ3H_{\Lambda}^{3}\mathrm{H} has been reconstructed via its two-charged-body decay channel, i.e., Λ3H3He+π_{\Lambda}^{3}\mathrm{H} \rightarrow {}^{3}\mathrm{He} + \pi^{-}. A Blast-Wave model fit of the pTp_{\rm T}-differential spectra of all nuclear species measured by the ALICE collaboration suggests that the Λ3H_{\Lambda}^{3}\mathrm{H} kinetic freeze-out surface is consistent with that of other nuclei. The ratio between the integrated yields of Λ3H_{\Lambda}^{3}\mathrm{H} and 3He^3\mathrm{He} is compared to predictions from the statistical hadronisation model and the coalescence model, with the latter being favoured by the presented measurements

    Particle production as a function of charged-particle flattenicity in pp collisions at s\sqrt{s} = 13 TeV

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    International audienceThis paper reports the first measurement of the transverse momentum (pTp_{\mathrm{T}}) spectra of primary charged pions, kaons, (anti)protons, and unidentified particles as a function of the charged-particle flattenicity in pp collisions at s=13\sqrt{s}=13 TeV. Flattenicity is a novel event shape observable that is measured in the pseudorapidity intervals covered by the V0 detector, 2.8<η<5.12.8<\eta<5.1 and 3.7<η<1.7-3.7<\eta<-1.7. According to QCD-inspired phenomenological models, it shows sensitivity to multiparton interactions and is less affected by biases towards larger pTp_{\mathrm{T}} due to local multiplicity fluctuations in the V0 acceptance than multiplicity. The analysis is performed in minimum-bias (MB) as well as in high-multiplicity events up to pT=20p_{\mathrm{T}}=20 GeV/cc. The event selection requires at least one charged particle produced in the pseudorapidity interval η<1|\eta|<1. The measured pTp_{\mathrm{T}} distributions, average pTp_{\mathrm{T}}, kaon-to-pion and proton-to-pion particle ratios, presented in this paper, are compared to model calculations using PYTHIA 8 based on color strings and EPOS LHC. The modification of the pTp_{\mathrm{T}}-spectral shapes in low-flattenicity events that have large event activity with respect to those measured in MB events develops a pronounced peak at intermediate pTp_{\mathrm{T}} (2<pT<82<p_{\mathrm{T}}<8 GeV/cc), and approaches the vicinity of unity at higher pTp_{\mathrm{T}}. The results are qualitatively described by PYTHIA, and they show different behavior than those measured as a function of charged-particle multiplicity based on the V0M estimator

    Measurement of the impact-parameter dependent azimuthal anisotropy in coherent ρ0 photoproduction in Pb–Pb collisions at √sNN = 5.02 TeV

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    The first measurement of the impact-parameter dependent angular anisotropy in the decay of coherently photoproduced ρ0 mesons is presented. The ρ0 mesons are reconstructed through their decay into a pion pair. The measured anisotropy corresponds to the amplitude of the cos(2ϕ) modulation, where ϕ is the angle between the two vectors formed by the sum and the difference of the transverse momenta of the pions, respectively. The measurement was performed by the ALICE Collaboration at the LHC using data from ultraperipheral Pb−Pb collisions at a center-of-mass energy of sNN−−−√ = 5.02 TeV per nucleon pair. Different impact-parameter regions are selected by classifying the events in nuclear-breakup classes. The amplitude of the cos(2ϕ) modulation is found to increase by about one order of magnitude from large to small impact parameters. Theoretical calculations, which describe the measurement, explain the cos(2ϕ) anisotropy as the result of a quantum interference effect at the femtometer scale that arises from the ambiguity as to which of the nuclei is the source of the photon in the interaction

    Investigating the nature of the K∗0(700) state with π±K0S correlations at the LHC

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    The first measurements of femtoscopic correlations with the particle pair combinations π±K0S in pp collisions at s√=13 TeV at the Large Hadron Collider (LHC) are reported by the ALICE experiment. Using the femtoscopic approach, it is shown that it is possible to study the elusive K∗0(700) particle that has been considered a tetraquark candidate for over forty years. Boson source parameters and final-state interaction parameters are extracted by fitting a model assuming a Gaussian source to the experimentally measured two-particle correlation functions. The final-state interaction is modeled through a resonant scattering amplitude, defined in terms of a mass and a coupling parameter, decaying into a π±K0S pair. The extracted mass and Breit-Wigner width, derived from the coupling parameter, of the final-state interaction are found to be consistent with previous measurements of the K∗0(700). The small value and increasing behavior of the correlation strength with increasing source size support the hypothesis that the K∗0(700) is a four-quark state, i.e. a tetraquark state. This latter trend is also confirmed via a simple geometric model that assumes a tetraquark structure of the K∗0(700) resonance

    Investigating strangeness enhancement in jet and medium via ϕ\phi(1020) production in p-Pb collisions at sNN\sqrt{s_{\rm NN}} = 5.02 TeV

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    International audienceThis work aims to differentiate strangeness produced from hard processes (jet-like) and softer processes (underlying event) by measuring the angular correlation between a high-momentum trigger hadron (h) acting as a jet-proxy and a produced strange hadron (ϕ(1020)\phi(1020) meson). Measuring hϕ-\phi correlations at midrapidity in p-Pb collisions at sNN\sqrt{s_{\rm NN}} = 5.02 TeV as a function of event multiplicity provides insight into the microscopic origin of strangeness enhancement in small collision systems. The jet-like and the underlying-event-like strangeness production are investigated as a function of event multiplicity. They are also compared between a lower and higher momentum region. The evolution of the per-trigger yields within the near-side (aligned with the trigger hadron) and away-side (in the opposite direction of the trigger hadron) jet is studied separately, allowing for the characterization of two distinct jet-like production regimes. Furthermore, the hϕ-\phi correlations within the underlying event give access to a production regime dominated by soft production processes, which can be compared directly to the in-jet production. Comparisons between hϕ-\phi and dihadron correlations show that the observed strangeness enhancement is largely driven by the underlying event, where the ϕ/h\phi/\mathrm{h} ratio is significantly larger than within the jet regions. As multiplicity increases, the fraction of the total ϕ(1020)\phi(1020) yield coming from jets decreases compared to the underlying event production, leading to high-multiplicity events being dominated by the increased strangeness production from the underlying event

    Measurement of Λ3H{}_{\Lambda}^{3}\mathrm{H} production in Pb-Pb collisions at sNN\sqrt{s_{\mathrm{NN}}} = 5.02 TeV

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    International audienceThe first measurement of Λ3H_{\Lambda}^{3}\mathrm{H} and Λ3H^3_ {\overline{\Lambda}}\overline{\mathrm{H}} differential production with respect to transverse momentum and centrality in Pb-Pb collisions at sNN=5.02\sqrt{s_{\mathrm{NN}}}=5.02~TeV is presented. The Λ3H_{\Lambda}^{3}\mathrm{H} has been reconstructed via its two-charged-body decay channel, i.e., Λ3H3He+π_{\Lambda}^{3}\mathrm{H} \rightarrow {}^{3}\mathrm{He} + \pi^{-}. A Blast-Wave model fit of the pTp_{\rm T}-differential spectra of all nuclear species measured by the ALICE collaboration suggests that the Λ3H_{\Lambda}^{3}\mathrm{H} kinetic freeze-out surface is consistent with that of other nuclei. The ratio between the integrated yields of Λ3H_{\Lambda}^{3}\mathrm{H} and 3He^3\mathrm{He} is compared to predictions from the statistical hadronisation model and the coalescence model, with the latter being favoured by the presented measurements

    Investigating Λ\Lambda baryon production in p-Pb collisions in jets and underlying event using angular correlations

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    International audienceFirst measurements of hadron(h)Λ-\Lambda azimuthal angular correlations in p-Pb collisions at sNN\sqrt{s_{\rm NN}} = 5.02 TeV using the ALICE detector at the LHC are presented. These correlations are used to separate the production of associated Λ\Lambda baryons into three different kinematic regions, namely those produced in the direction of the trigger particle (near-side), those produced in the opposite direction (away-side), and those whose production is uncorrelated with the jet-axis (underlying event). The per-trigger associated Λ\Lambda yields in these regions are extracted, along with the near- and away-side azimuthal peak widths, and the results are studied as a function of associated particle pTp_{\rm T} and event multiplicity. Comparisons with the DPMJET event generator and previous measurements of the ϕ(1020)\phi(1020) meson are also made. The final results indicate that strangeness production in the highest multiplicity p-Pb collisions is enhanced relative to low multiplicity collisions in the jet-like regions, as well as the underlying event. The production of Λ\Lambda relative to charged hadrons is also enhanced in the underlying event when compared to the jet-like regions. Additionally, the results hint that strange quark production in the away-side of the jet is modified by soft interactions with the underlying event
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