Alternatively Assessing Conceptual Learning in an Emergency Clinical Environment—A Mixed Methods Design

Modeling cognitive processes in clinical learning environments is a necessary first step towards improving learning assessment and medical practice by using an alternative assessment model. Verbal protocol and cognitive content analyses are effective methods of exploring such cognitive processes. For the purpose of simplifying the discussion, we have labeled these processes as Identification of Information, Advanced Cognition, and Medical Cognitive Action. Exploring problem solving processes with Bayesian network techniques can characterize students\u27 dynamic learning processes quantitatively, identify differences in cognitive components at different stages of learning and better represent clinical problem solving features. We develop a hierarchical cognitive model as a cognitive assessment tool to describe the complex cognitive network relations, which can be applied to various clinical cognitive situations. The study concludes that the cognitive model was useful in identifying students\u27 learning trajectories by representing the different cognitive feature

Bayesian Inference of the Specific Shear and Bulk Viscosities of the Quark-Gluon Plasma at Crossover from ϕ\phi and Ω\Omega Observables

Due to their weak final state interactions, the $\phi$ meson and $\Omega$ baryon provide unique probes of the properties of the quark-gluon plasma (QGP) formed in relativistic heavy-ion collisions. Using the quark recombination model with the quark phase-space information parameterized in a viscous blastwave, we study the transverse-momentum spectra and elliptic flows of $\phi$ and $\Omega$ in Au+Au collisions at $\sqrt{s_{\rm NN}} = 200$ GeV and Pb+Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV. The viscous blastwave includes non-equilibrium deformations of thermal distributions due to shear and bulk stresses and thus carries information on the specific shear viscosity $\eta/s$ and the specific bulk viscosity $\zeta/s$ of the QGP. We perform a model-to-data comparison with Bayesian inference and simultaneously obtain $\eta/s=(2.08^{+1.10}_{-1.09})/4\pi$ and $\zeta/s= 0.06^{+0.04}_{-0.04}$ at $90\%$ C.L. for the baryon-free QGP at crossover temperature of about $160$ MeV. Our work provides a novel approach to simultaneously determine the $\eta/s$ and $\zeta/s$ of the QGP at hadronization.Comment: 7 pages, 3 figures, 1 table. Presentation improved and discussions added. Accepted version to appear in PR

Parameterizing Smooth Viscous Fluid Dynamics With a Viscous Blast Wave

Blast wave fits can capture essential features of global properties of systems near kinetic equilibrium. They usually provide temperature fields and collective velocity fields on a given hypersurface. We investigate how faithful the viscous blast wave introduced in [1] (Z. Yang and R. J. Fries, arXiv:1807.03410), can reproduce the given temperature and specific shear viscosity at freeze-out of a viscous fluid dynamic calculation, if the final spectrum and elliptic flow of several particle species are fitted. We focus here on fluid dynamic simulations appropriate for high energy nuclear collisions at current collider energies. We find that specific shear viscosities are reproduced to good accuracy by viscous blast wave fits while temperatures tend to be slightly underpredicted. We quantify the deviations of fitted from true quantities for some examples. The maps we obtain can be used to improve raw results obtained from viscous blast wave fits.Comment: 14 pages, 7 figures; v2: a few references adde

A SELF-CONSISTENT VISCOUS BLAST WAVE MODEL AND ITS APPLICATIONS TO HIGH ENERGY NUCLEAR COLLISIONS

Collisions of nuclei at large energies create fireballs of hot hadronic matter and quark gluon plasma. The properties of these extreme forms of nuclear matter can be studied by the experiments at the Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC). In this work we refine tools to study the matter in nuclear collisions and we infer the shear viscosity of hot hadronic matter from data. Hadronic observables in the final stage of the heavy-ion collisions can be described well by hydrodynamics or blastwave parameterizations. We construct a blastwave model with self-consistent viscous corrections by calculating the viscous stress tensor from the parameterized flow field in the Navier-Stokes approximation. We improve similar models developed earlier by using a more realistic flow field and by calculating the time derivative terms by solving the ideal hydrodynamic equations analytically. Such a viscous blastwave can describe important features of the fireball without running numerically expensive hydrodynamics. We can validate the blastwave by comparison with established hydrodynamic calculations. We can quantify the uncertainty and bias from the simplifications of hypersurface and flow field by systematically comparing to hydrodynamic calculations with resonance decays and bulk stress included. As a first application, we focus on the freeze-out temperature Tvfo and the specific shear viscosity η/s of hot hadronic matter at that temperature. We use statistical Bayesian analysis tools to extract η/s at T = Tvfo from experimental data. Our approach is complementary to existing extractions from viscous hydrodynamics. The latter is sensitive to an averaged shear viscosity during that time evolution while our analysis is only sensitive to the shear viscosity at kinetic freeze-out. We can use the comparison to hydrodynamics to remove some systematic bias in the extraction results of T and η/s. We can also use the viscous blastwave to provide realistic input for quark recombination models. These calculations had previously assumed breaking of thermal equilibrium in a naive way which is now replaced by viscous corrections to equilibrium. We get the quark spectra at T ≈ Tvc from the blastwave and then use recombination to get spectra and elliptic flow vv2 of identified hadrons at intermediate transverse momentum vpr (2GeV/c < 6GeV/c). We find a moderate breaking of the constituent quark number scaling (QNS) law consistent with experimental data from RHIC and LHC. Thus, we demonstrate that the QNS law is not a necessary feature of quark recombinatio