QCD Matter Thermalization at RHIC and LHC

Employing the perturbative QCD inspired parton cascade, we investigate kinetic and chemical equilibration of the partonic matter created in central heavy ion collisions at RHIC and LHC energies. Two types of initial conditions are chosen. One is generated by the model of wounded nucleons using the PYTHIA event generator and Glauber geometry. Another is considered as a color glass condensate. We show that kinetic equilibration is almost independent on the chosen initial conditions, whereas there is a sensitive dependence for chemical equilibration. The time scale of thermalization lies between 1 and 1.5 fm/c. The final parton transverse energy obtained from BAMPS calculations is compared with the RHIC data and is estimated for the LHC energy.Comment: 8 pages, 10 figures, plenary talk at International Conference on Strangeness in Quark Matter 2008, Beijing, China, October 6-10, 200

A randomised proof-of-concept trial on the effectiveness of a game-based training of phoneme-grapheme correspondences in pre-readers

Background: Learning which letters correspond to which speech sounds is fundamental for learning to read. Based on previous experimental studies, we developed a serious game aiming to boost letter-speech sound (L-SS) correspondences in a motivational game environment. Objectives: The goal of this study was to determine the efficacy of this game in training L-SS correspondences in pre-readers. Additionally, an extended version of the game was developed given the importance of handwriting in audio-visual integration. We established whether including a motoric component in the game boosted the letter-speech sound training on top of the effect of the game without the motoric component. Methods: One-hundred forty-five kindergartners were randomly allocated to play either the standard audio-visual version of the game, the motoric version or a control math game. All children were pre- and post-tested on L-SS knowledge and reading accuracy. Results and conclusions: We found that playing the game enhanced pre-readers' L-SS knowledge, but not reading accuracy, after a short, intensive intervention period of 3 weeks. However, children who played the motoric version of the game did not differ significantly from either the standard or the control condition. Implications: This game was efficient in training L-SS correspondences in pre-readers. These results suggest that this game might be useful as a preventive evidence-based intervention for at-risk children in kindergarten who might benefit from a head start before learning how to read. Future studies are needed to examine whether a longer intervention period results in L-SS knowledge being translated into reading skills.</p

The Study of Noncollectivity by the Forward-Backward Multiplicity Correlation Function

We propose a forward-backward multiplicity correlation function $C^N_{FB}$, which is experimentally accessible, to measure the noncollectivity contribution. We find that $C^N_{FB}$ is sensitive to the jet contribution for the particle-rich case. Surprisingly, it will automatically decrease for the particle-rare case. Our study indicates that similar decreasing trend observed previously is mainly driven by particle scarcity instead of jets. The function is studied in Au+Au collision at $\sqrt{s_{NN}}=200$ GeV with a multiphase transport model (AMPT). We find that the jet fraction is about 10% at transverse momentum ($p_T$) around 2.5 GeV/$c$ and reaches up to 30% at 3.5 GeV/$c$. The implication of this study in the investigation of the noncollectivity contribution in elliptic anisotropy parameter $v_2$ is also discussed.Comment: 5 pages, 4 figure

Universal and language-specific predictors of early word reading in a foreign language:An analysis of the skills that underlie reading acquisition in three different orthographies

A central question in the field of foreign language acquisition is whether the processes involved in reading development in a foreign language are universal or dependent on characteristics of the specific language involved. We investigated the impact of orthographic depth and writing system on word reading acquisition in a foreign orthography, by studying children who are proficient readers in the transparent alphabetic Dutch orthography and who learn to read simultaneously in the transparent alphabetic Spanish orthography, the nontransparent alphabetic French orthography and the nonalphabetic Chinese orthography. Results showed that the skills that underlie foreign language word reading are not universal, but are different for alphabetic and nonalphabetic orthographies, and are also different for transparent and nontransparent alphabetic orthographies, albeit to a lesser extent. Word reading acquisition in transparent alphabetic Spanish depended mainly on reading skills in the native language. In contrast, in nontransparent alphabetic French and nonalphabetic Chinese, word reading was mainly influenced by cognitive skills: French word reading by phonological awareness and verbal intelligence, and Chinese word reading by verbal and nonverbal intelligence. Findings thus suggest that the processes underlying foreign language word reading acquisition are not universal but rather depend on the specific language involved

Influence of jets and resonance decays on the constituent quark scaling of elliptic flow

The Monte Carlo HYDJET++ model, that contains both hydrodynamic state and jets, is applied to study the influence of the interplay between soft and hard processes on the formation of the elliptic flow in heavy-ion collisions at RHIC and LHC energies. Jets are found to cease the hydro-like increase of the elliptic flow with rising p_T. Since jets are more influential at LHC than at RHIC, the v_2 at LHC should be weaker than that at RHIC. Violation of the number-of-constituent-quark (NCQ) scaling is predicted. The decays of resonances are found to enhance the low-p_T part of the elliptic flow of pions and light baryons, and work toward the fulfillment of the NCQ scaling.Comment: 6 pages, talk given at the International Conference on Strangeness in Quark Matter 2009 (SQM09

Jet Tomography of Au+Au Reactions Including Multi-gluon Fluctuations

Jet tomography is the analysis of the attenuation pattern of high transverse momentum hadrons to determine certain line integral transforms of the density profile of the QCD matter produced in ultra-relativistic nuclear collisions. In this letter, we calculate the distortion of jet tomography due to multi-gluon fluctuations within the GLV radiative energy loss formalism. We find that fluctuations of the average gluon number, ~ 3 for RHIC initial conditions, reduce the attenuation of pions by approximately a factor Z ~ 0.4-0.5. Therefore the plasma density inferred from jet tomography without fluctuations must be enhanced by a factor 1/Z ~ 2.Comment: 6 pages, 4 .eps figures, uses REVTEX and bbox.st

Explaining individual differences in young English language learners’ vocabulary knowledge: The role of Extramural English Exposure and motivation

The role of motivation and extramural English exposure in explaining individual differences in young English language learners’ (YELLs’) English performance is unclear. In this study, we hypothesized that different types of extramural English exposure predict YELLs’ (Dutch, N = 262, 10 years old, grade 4) oral and written English receptive vocabulary knowledge, and that motivational factors act as mediators. A distinction was made between YELLs learning English only informally through extramural English exposure and YELLs learning English also formally at school. A path analysis showed that the total impact of familial extramural English exposure and extramural English exposure through entertaining media was greater for the YELLs learning English informally, compared to YELLs learning English also formally. While the sources of extramural English exposure were directly predictive of performance with regard to both oral and written English receptive vocabulary tests for YELLs’ learning English informally, linguistic self-confidence fully mediated these relationships for YELLs learning English formally. Our findings call for further development of theoretical frameworks explaining the relationship between YELLs’ motivation and exposure