L'utilisation des moteurs de recherche par les jeunes : Impact des connaissances du domaine et des connaissances procédurales sur les stratégies d'exploration visuelle

International audienceDans une expérimentation conduite avec 53 élèves de CM2 utilisant la technique de l'oculométrie, nous tentons de mieux comprendre les stratégies d'exploration visuelle utilisées par de très jeunes usagers lors d'une tâche de recherche d'information sur le Web. Plus précisément, notre étude vise d'une part, à déterminer si plusieurs types de stratégies d'exploration visuelle d'une page de résultats proposés par un moteur de recherche (ou SERP) peuvent être déterminés et d'autre part, si des facteurs psychologiques (ici, les connaissances du domaine et les connaissances procédurales) peuvent influencer ces stratégies. Nos résultats ont principalement montré d'une part, que quatre stratégies d'exploration visuelle peuvent effectivement être distinguées et d'autre part, que le niveau de connaissances procédurales influence ces mêmes stratégies

Roles of consonant status and sonority in printed syllable processing: Evidence from illusory conjunction and audio-visual recognition tasks in French adults.

Notre étude visait à étudier le rôle du codage phonologique en lecture silencieuse chez des adultes français. Nous avons particulièrement étudié le profil de sonorité, les règles phonotactiques ainsi que la structure syllabique aux frontières syllabiques grâce à une tâche de reconnaissance audio-visuelle et au paradigme des conjonctions illusoires (Prinzmetal, Treiman & Rho, 1986). Nous avons évalué si les adultes experts avaient recours aux syllabes. Nous souhaitions également observer si le codage phonologique était sensible à des facteurs linguistiques tels que le statut de la consonne pivot et au profil de sonorité. Les résultats obtenus dans les deux expériences ont montré que les adultes s’appuyaient sur les syllabes. Cependant, le recours aux syllabes était influencé et contraint par la phonotactique. En effet, les adultes se sont montrés sensibles aux profils de sonorité pour déterminer les frontières syllabiques. Ainsi, les profils intervocaliques respectant un cycle de sonorité optimal (i.e., coda liquide-attaque plosive) ont été préférés aux autres profils de sonorité. Ces données s’accordent avec les théories linguistiques selon lesquelles le contact optimal entre deux syllabe repose sur une coda plus sonore que la consonne subséquente en position d’attaque (e.g., Clements, 1990).The paper investigates how French readers visually process consonant clusters between two syllables. First, we aimed at assessing whether skilled adults were sensitive to syllable-sized units. Second, we wondered whether syllable processing depended on linguistic characteristics of consonant clusters such as consonant status and sonority profile. Two visual recognition tasks were used: the classical illusory conjunction paradigm (Prinzmetal, Treiman & Rho, 1986) and an original audio-visual recognition tasks. The results showed that syllable-sized units were used in both tasks. However, sonority profile and consonant status modulated syllable processing whatever the task. Consonant clusters whose sonority profile was ‘sonorant coda-obstruent onset’ (e.g. ‘LP’ in ‘TOLPUDE’) was preferred to all other sonority profiles. These behavioural results were in line with linguistic principles according to which the best contact between two syllables lies on a peak in sonority at the end of the first syllable following by a drop in sonority at beginning of the subsequent one (e.g., Hooper, 1972 ; Clements, 1990)

Roles of consonant status and sonority in printed syllable processing: Evidence from illusory conjunction and audio-visual recognition tasks in French adults.

Notre étude visait à étudier le rôle du codage phonologique en lecture silencieuse chez des adultes français. Nous avons particulièrement étudié le profil de sonorité, les règles phonotactiques ainsi que la structure syllabique aux frontières syllabiques grâce à une tâche de reconnaissance audio-visuelle et au paradigme des conjonctions illusoires (Prinzmetal, Treiman & Rho, 1986). Nous avons évalué si les adultes experts avaient recours aux syllabes. Nous souhaitions également observer si le codage phonologique était sensible à des facteurs linguistiques tels que le statut de la consonne pivot et au profil de sonorité. Les résultats obtenus dans les deux expériences ont montré que les adultes s’appuyaient sur les syllabes. Cependant, le recours aux syllabes était influencé et contraint par la phonotactique. En effet, les adultes se sont montrés sensibles aux profils de sonorité pour déterminer les frontières syllabiques. Ainsi, les profils intervocaliques respectant un cycle de sonorité optimal (i.e., coda liquide-attaque plosive) ont été préférés aux autres profils de sonorité. Ces données s’accordent avec les théories linguistiques selon lesquelles le contact optimal entre deux syllabe repose sur une coda plus sonore que la consonne subséquente en position d’attaque (e.g., Clements, 1990).The paper investigates how French readers visually process consonant clusters between two syllables. First, we aimed at assessing whether skilled adults were sensitive to syllable-sized units. Second, we wondered whether syllable processing depended on linguistic characteristics of consonant clusters such as consonant status and sonority profile. Two visual recognition tasks were used: the classical illusory conjunction paradigm (Prinzmetal, Treiman & Rho, 1986) and an original audio-visual recognition tasks. The results showed that syllable-sized units were used in both tasks. However, sonority profile and consonant status modulated syllable processing whatever the task. Consonant clusters whose sonority profile was ‘sonorant coda-obstruent onset’ (e.g. ‘LP’ in ‘TOLPUDE’) was preferred to all other sonority profiles. These behavioural results were in line with linguistic principles according to which the best contact between two syllables lies on a peak in sonority at the end of the first syllable following by a drop in sonority at beginning of the subsequent one (e.g., Hooper, 1972 ; Clements, 1990)

Investigación evaluativa de la formación docente en los institutos de la provincia de Córdoba. Adecuación a las necesidades que plantea el ejercicio profesional en las escuelas de nivel primario

Esta investigación evaluativa estudió la adecuación del trayecto de formación docente inicial a las necesidades que actualmente demandan los egresados, las escuelas y la comunidad en el ejercicio de la práctica profesional.Como objetivo se planteó analizar el grado de correspondencia de la propuesta curricular del trayecto de formación docente inicial con las demandas que hacen al ejercicio de la práctica profesional, los alumnos, las escuelas y la comunidad. Estas demandas se concretan en conocimientos y competencias para el desempeño profesional de los docentes en las escuelas donde realizaran su inserción laboral.Se tomó en cuenta: los conocimientos y competencias que el Ministerio de Educación ha definido. Las demandas que hacen la población en general y los directivos de instituciones escolares a la formación docentes acerca de estos conocimientos y competencias. La percepción de los egresados que se encuentran iniciando el ejercicio de la docencia, acerca de si su formación ha sido adecuada a las necesidades de su inserción laboral.A tal fin, se realizó un estudio exploratorio de 800 casos de la comunidad cordobesa, un cuestionario de opinión a directivos de escuelas primarias, encuesta a egresados de institutos cohortes 2000 a 2005 que están en ejercicio y revisión de contenidos de 154 planificaciones didácticas de institutos formadores.Los resultados obtenidos alertan sobre áreas claves de la formación de los nuevos maestros donde los conocimientos y competencias alcanzados no responden adecuadamente a los desafíos de la compleja práctica profesional aportando datos relevantes acerca de los cambios necesarios en las propuestas pedagógicas de la formación docent

Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm{NN}}} = 2.76 TeV

The inclusive transverse momentum ($p_{\rm T}$) distributions of primary charged particles are measured in the pseudo-rapidity range $|\eta|<0.8$ as a function of event centrality in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}=2.76$ TeV with ALICE at the LHC. The data are presented in the $p_{\rm T}$ range $0.15<p_{\rm T}<50$ GeV/$c$ for nine centrality intervals from 70-80% to 0-5%. The Pb-Pb spectra are presented in terms of the nuclear modification factor $R_{\rm{AA}}$ using a pp reference spectrum measured at the same collision energy. We observe that the suppression of high-$p_{\rm T}$ particles strongly depends on event centrality. In central collisions (0-5%) the yield is most suppressed with $R_{\rm{AA}}\approx0.13$ at $p_{\rm T}=6$-7 GeV/$c$. Above $p_{\rm T}=7$ GeV/$c$, there is a significant rise in the nuclear modification factor, which reaches $R_{\rm{AA}} \approx0.4$ for $p_{\rm T}>30$ GeV/$c$. In peripheral collisions (70-80%), the suppression is weaker with $R_{\rm{AA}} \approx 0.7$ almost independently of $p_{\rm T}$. The measured nuclear modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/284

Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}=2.76 TeV

The elliptic, $v_2$, triangular, $v_3$, and quadrangular, $v_4$, azimuthal anisotropic flow coefficients are measured for unidentified charged particles, pions and (anti-)protons in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV with the ALICE detector at the Large Hadron Collider. Results obtained with the event plane and four-particle cumulant methods are reported for the pseudo-rapidity range $|\eta|<0.8$ at different collision centralities and as a function of transverse momentum, $p_{\rm T}$, out to $p_{\rm T}=20$ GeV/$c$. The observed non-zero elliptic and triangular flow depends only weakly on transverse momentum for $p_{\rm T}>8$ GeV/$c$. The small $p_{\rm T}$ dependence of the difference between elliptic flow results obtained from the event plane and four-particle cumulant methods suggests a common origin of flow fluctuations up to $p_{\rm T}=8$ GeV/$c$. The magnitude of the (anti-)proton elliptic and triangular flow is larger than that of pions out to at least $p_{\rm T}=8$ GeV/$c$ indicating that the particle type dependence persists out to high $p_{\rm T}$.Comment: 16 pages, 5 captioned figures, authors from page 11, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186

Charge separation relative to the reaction plane in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}= 2.76 TeV

Measurements of charge dependent azimuthal correlations with the ALICE detector at the LHC are reported for Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV. Two- and three-particle charge-dependent azimuthal correlations in the pseudo-rapidity range $|\eta| < 0.8$ are presented as a function of the collision centrality, particle separation in pseudo-rapidity, and transverse momentum. A clear signal compatible with a charge-dependent separation relative to the reaction plane is observed, which shows little or no collision energy dependence when compared to measurements at RHIC energies. This provides a new insight for understanding the nature of the charge dependent azimuthal correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286

A note on comonotonicity and positivity of the control components of decoupled quadratic FBSDE

In this small note we are concerned with the solution of Forward-Backward Stochastic Differential Equations (FBSDE) with drivers that grow quadratically in the control component (quadratic growth FBSDE or qgFBSDE). The main theorem is a comparison result that allows comparing componentwise the signs of the control processes of two different qgFBSDE. As a byproduct one obtains conditions that allow establishing the positivity of the control process.Comment: accepted for publicatio

Measurement of charm production at central rapidity in proton-proton collisions at s=2.76\sqrt{s} = 2.76 TeV

The $p_{\rm T}$-differential production cross sections of the prompt (B feed-down subtracted) charmed mesons D$^0$, D$^+$, and D$^{*+}$ in the rapidity range $|y|<0.5$, and for transverse momentum $1< p_{\rm T} <12$ GeV/$c$, were measured in proton-proton collisions at $\sqrt{s} = 2.76$ TeV with the ALICE detector at the Large Hadron Collider. The analysis exploited the hadronic decays D$^0 \rightarrow$K$\pi$, D$^+ \rightarrow$K$\pi\pi$, D$^{*+} \rightarrow$D$^0\pi$, and their charge conjugates, and was performed on a $L_{\rm int} = 1.1$ nb$^{-1}$ event sample collected in 2011 with a minimum-bias trigger. The total charm production cross section at $\sqrt{s} = 2.76$ TeV and at 7 TeV was evaluated by extrapolating to the full phase space the $p_{\rm T}$-differential production cross sections at $\sqrt{s} = 2.76$ TeV and our previous measurements at $\sqrt{s} = 7$ TeV. The results were compared to existing measurements and to perturbative-QCD calculations. The fraction of cdbar D mesons produced in a vector state was also determined.Comment: 20 pages, 5 captioned figures, 4 tables, authors from page 15, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/307

Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV

Inclusive transverse momentum spectra of primary charged particles in Pb-Pb collisions at $\sqrt{s_{_{\rm NN}}}$ = 2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross section. The measured charged particle spectra in $|\eta|<0.8$ and $0.3 < p_T < 20$ GeV/$c$ are compared to the expectation in pp collisions at the same $\sqrt{s_{\rm NN}}$, scaled by the number of underlying nucleon-nucleon collisions. The comparison is expressed in terms of the nuclear modification factor $R_{\rm AA}$. The result indicates only weak medium effects ($R_{\rm AA} \approx$ 0.7) in peripheral collisions. In central collisions, $R_{\rm AA}$ reaches a minimum of about 0.14 at $p_{\rm T}=6$-7GeV/$c$ and increases significantly at larger $p_{\rm T}$. The measured suppression of high-$p_{\rm T}$ particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb-Pb collisions at the LHC.Comment: 15 pages, 5 captioned figures, 3 tables, authors from page 10, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/98