The effects of the late 2000s global financial crisis on Australia’s construction demand

An accurate measurement of the impacts of external shocks on construction demand will enable construction industry policymakers and developers to make allowances for future occurrences and advance the construction industry in a sustainable manner. This paper aims to measurethe dynamic effects of the late 2000s global financial crisis on the level of demand in the Australian construction industry. The vector error correction (VEC) model with intervention indicators is employed to estimate the external impact from the crisis on a macro-level construction economic indicator, namely construction demand. The methodology comprises six main stages to produce appropriate VEC models that describe the characteristics of the underlying process. Research findings suggestthat overall residential and non-residential construction demand were affected significantly by the recent crisis and seasonality. Non-residentialconstruction demand was disrupted more than residential construction demand at the crisis onset. The residential constructionindustry is more reactive and is able to recover faster following the crisis in comparison with the non-residential industry. The VEC model with intervention indicators developed in this study can be used as an experiment for an advanced econometric method. This can be used to analyse the effects of special eventsand factors not only on construction but also on other industries

Shedding light on the pion production in heavy-ion collisions for constraining the high-density symmetry energy

Within the framework of the quantum molecular dynamics transport model, the pion production and constraint of the high-density symmetry energy in heavy-ion collisions near threshold energy have been thoroughly investigated. The energy conservation in the decay of resonances and reabsorption of pions in nuclear medium are taken into account. The density profile of pion production, energy conservation and pion potential are analyzed by the model. The isospin diffusion in the low-density region (0.2$\rho_{0}$ - 0.8$\rho_{0}$) and high-density region (1.2$\rho_{0}$ - 1.8$\rho_{0}$) is investigated by analyzing the neutron/proton and $\pi^{-}/\pi^{+}$ ratios in the isotopic reactions of $^{132}$Sn + $^{124}$Sn and $^{108}$Sn + $^{112}$Sn at the incident energy of 270 MeV/nucleon, in which the symmetry energy manifests the opposite contribution. The controversial conclusion of the $\pi^{-}/\pi^{+}$ ratio for constraining the high-density symmetry energy by different transport models is clarified. A soft symmetry energy with the slope parameter of $L(\rho_{0}) = 42\pm 25$ MeV by using the standard error analysis within the range of $1\sigma$ is obtained by analyzing the experimental data from the S$\pi$RIT collaboration.Comment: 8 pages, 7 figure

Collective flows of clusters and pions in heavy-ion collisions at GeV energies

Within the framework of the quantum molecular dynamics transport model, the collective flows of clusters and pions in heavy-ion collisions have been systematically investigated. The clusters are recognized by the Wigner phase-space density approach at the stage of freeze out in nuclear collisions, i.e., deuteron, triton, $^{3}$He and $\alpha$. The directed and elliptic flows of protons and deuterons in the reaction of $^{197}$Au+$^{197}$Au at incident energy 1.23\emph{A} GeV are nicely consistent with the recent HADES data. The higher order collective flows, i.e., triangular and quadrangle flows, manifest the opposite trends with the less amplitude in comparison with the rapidity distributions of directed and elliptic flows. The flow structure of $^{3}$He and $\alpha$ is very similar to the proton spectra. The influence of the pion potential on the pion production is systematically investigated and compared with the FOPI data via the transverse momentum, longitudinal rapidity and collective flows in collisions of $^{197}$Au + $^{197}$Au. It is manifested that the pion yields are slightly suppressed in the domain of mid-rapidity and high momentum. The antiflow phenomena is reduced by implementing the pion potential and more consistent with the FOPI data in collisions of $^{197}$Au+$^{197}$Au at the incident energy 1.5\emph{A} GeV.Comment: 11 pages, 9 figures. arXiv admin note: substantial text overlap with arXiv:2302.0213

BIVAS: A scalable Bayesian method for bi-level variable selection with applications

In this paper, we consider a Bayesian bi-level variable selection problem in high-dimensional regressions. In many practical situations, it is natural to assign group membership to each predictor. Examples include that genetic variants can be grouped at the gene level and a covariate from different tasks naturally forms a group. Thus, it is of interest to select important groups as well as important members from those groups. The existing Markov Chain Monte Carlo (MCMC) methods are often computationally intensive and not scalable to large data sets. To address this problem, we consider variational inference for bi-level variable selection (BIVAS). In contrast to the commonly used mean-field approximation, we propose a hierarchical factorization to approximate the posterior distribution, by utilizing the structure of bi-level variable selection. Moreover, we develop a computationally efficient and fully parallelizable algorithm based on this variational approximation. We further extend the developed method to model data sets from multi-task learning. The comprehensive numerical results from both simulation studies and real data analysis demonstrate the advantages of BIVAS for variable selection, parameter estimation and computational efficiency over existing methods. The method is implemented in R package `bivas' available at https://github.com/mxcai/bivas

A Research on Students’ Needs for Follow-up Curriculum of College English

Increased universities and colleges offer the undergraduates with more follow-up courses with the further reform in college English education in China. An investigation on self-evaluation, difficulty, and willingness of undergraduates in learning English further was made in order to design more appropriate and adaptable follow-up courses. This research shows that the majority of undergraduates are not satisfied with their English level in English skills, especially speaking. Most undergraduates are willing to take further college English courses with the purpose of finding a better job, but they prefer to choose some comparatively simple and entertaining selective courses such as movie appreciation other than some courses for developing skills. The data achieved leaves some implications on college English education, lays some bases for English education reform and provides new challenge for college English teachers