Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV

Peer reviewe

Extending the use of the conceptions of learning and teaching (COLT) instrument to the postgraduate setting

© 2021, The Author(s). Background: Several studies have shown that conceptions of teachers on teaching and learning can influence the teaching practices and behavior in higher education. This association is also found in undergraduate medical education but not yet established in postgraduate medical setting. An instrument, Conceptions of Learning and Teaching (COLT) was developed to measure conception of teachers in undergraduate medical education. COLT is a 3-factor 18-item questionnaire. The objective of this study is to evaluate if COLT is valid for postgraduate medical education. Methods: We invited postgraduate clinical faculty from 3 hospitals in the Netherlands to fill out the COLT. Confirmatory and exploratory factor analysis were performed to evaluate the fit of the postgraduate clinical faculty data to the COLT. Analysis of variance was done to evaluate if there was difference among the 3 hospitals in terms of the response by the clinical faculty. Results: Confirmatory factor analysis showed that the postgraduate faculty data had a 2 factor structure after removal of five items. These factors were Teacher Centeredness (TC) and combined Appreciation of Active Learning and Orientation to Professional Practice (A-P) and were considered as comparable to the factors in the original COLT, expressing the post-graduate learning and teaching setting. As several items were removed, the fit was suboptimal, yet did suggest validity for use of the COLT for postgraduate medical education. Conclusion: The modified COLT can be used to measure conceptions of teaching and learning in postgraduate medical education. We recommend further study to improve the factor structure of the modified COLT

Towards a student-centered education: Validation of the Italian version of the Conceptions of Learning and Teaching questionnaire

Many medical schools have transitioned from traditional teacher-centred education to active student-centred education. The Conception of Learning and Teaching (COLT) questionnaire investigates teachers’ conceptions of learning and teaching in student-centred medical education. This observational and multicentred study aims to validate the Italian version of the Conceptions of Learning and Teaching (COLT-IT) questionnaire and assess the Italian medical educators’ learning and teaching conceptions. To develop the COLT-IT, a back-translation was performed. The COLT-IT and socio-demographic questionnaires were electronically distributed to educators across 13 Italian medical schools. Analyses included explorative factor analysis (EFA), confirmatory factor analysis (CFA), and reliability analysis. A total of 394 medical teachers completed the survey. Although the EFA suggested retaining three factors, statistical conditions led to the exclusion of eleven of the original eighteen items and one factor. The CFA confirmed the bi-dimensional structure of the COLT-IT. The two-factor scale retained the original naming of subscales: Teacher centredness (TC) and Appreciation of active learning (AL). Approximately 50% of participants exhibited high levels of AL, while scores in the TC subscale were more varied. No differences emerged based on gender, age, or the geographical location of the medical school. The 7-item COLT-IT is a reliable, valid, robust, and easy-to-administer tool for promoting and monitoring the implementation of a student-centred approach in medical education

Multi-strange baryon production in pp collisions at √s=7 TeV with ALICE

A measurement of the multi-strange Ξ− and Ω− baryons and their antiparticles by the ALICE experiment at the CERN Large Hadron Collider (LHC) is presented for inelastic proton–proton collisions at a centre-of-mass energy of 7 TeV. The transverse momentum (pT) distributions were studied at mid-rapidity (|y|6.0 GeV/c. We also illustrate the difference between the experimental data and model by comparing the corresponding ratios of (Ω−+Ω¯+)/(Ξ−+Ξ¯+) as a function of transverse mass

Coherent J/ψ photoproduction in ultra-peripheral Pb–Pb collisions at √sNN=2.76 TeV

The ALICE Collaboration has made the first measurement at the LHC of J/ψ photoproduction in ultra-peripheral Pb–Pb collisions at sNN=2.76 TeV. The J/ψ is identified via its dimuon decay in the forward rapidity region with the muon spectrometer for events where the hadronic activity is required to be minimal. The analysis is based on an event sample corresponding to an integrated luminosity of about 55 μb−1. The cross section for coherent J/ψ production in the rapidity interval −3.6<y<−2.6 is measured to be dσJ/ψcoh/dy=1.00±0.18(stat)−0.26+0.24(syst) mb. The result is compared to theoretical models for coherent J/ψ production and found to be in good agreement with those models which include nuclear gluon shadowing

Freeze-out radii extracted from three-pion cumulants in pp, p–Pb and Pb–Pb collisions at the LHC

In high-energy collisions, the spatio-temporal size of the particle production region can be measured using the Bose–Einstein correlations of identical bosons at low relative momentum. The source radii are typically extracted using two-pion correlations, and characterize the system at the last stage of interaction, called kinetic freeze-out. In low-multiplicity collisions, unlike in high-multiplicity collisions, two-pion correlations are substantially altered by background correlations, e.g. mini-jets. Such correlations can be suppressed using three-pion cumulant correlations. We present the first measurements of the size of the system at freeze-out extracted from three-pion cumulant correlations in pp, p–Pb and Pb–Pb collisions at the LHC with ALICE. At similar multiplicity, the invariant radii extracted in p–Pb collisions are found to be 5–15% larger than those in pp, while those in Pb–Pb are 35–55% larger than those in p–Pb. Our measurements disfavor models which incorporate substantially stronger collective expansion in p–Pb as compared to pp collisions at similar multiplicity

Coherent ψ(2S) photo-production in ultra-peripheral PbPb collisions at √sNN=2.76 TeV

We have performed the first measurement of the coherent ψ(2S) photo-production cross section in ultra-peripheral PbPb collisions at the LHC. This charmonium excited state is reconstructed via the ψ(2S)→l+l− and ψ(2S)→J/ψπ+π− decays, where the J/ψ decays into two leptons. The analysis is based on an event sample corresponding to an integrated luminosity of about 22 μb−1. The cross section for coherent ψ(2S) production in the rapidity interval −0.9<y<0.9 is dσψ(2S)coh/dy=0.83±0.19(stat+syst) mb. The ψ(2S) to J/ψ coherent cross section ratio is 0.34−0.07+0.08(stat+syst). The obtained results are compared to predictions from theoretical models

Ds+ meson production at central rapidity in proton–proton collisions at √s=7 TeV

The pT-differential inclusive production cross section of the prompt charm-strange meson Ds+ in the rapidity range |y|<0.5 was measured in proton–proton collisions at s=7 TeV at the LHC using the ALICE detector. The analysis was performed on a data sample of 2.98×108 events collected with a minimum-bias trigger. The corresponding integrated luminosity is Lint=4.8 nb−1. Reconstructing the decay Ds+→ϕπ+, with ϕ→K−K+, and its charge conjugate, about 480 Ds± mesons were counted, after selection cuts, in the transverse momentum range 2<pT<12 GeV/c. The results are compared with predictions from models based on perturbative QCD. The ratios of the cross sections of four D meson species (namely D0, D+, D⁎+ and Ds+) were determined both as a function of pT and integrated over pT after extrapolating to full pT range, together with the strangeness suppression factor in charm fragmentation. The obtained values are found to be compatible within uncertainties with those measured by other experiments in e+e−, ep and pp interactions at various centre-of-mass energies