您选择的条件: Sijia Li
  • Baryonic Effects on Lagrangian Clustering and Angular Momentum Reconstruction

    分类: 天文学 >> 天文学 提交时间: 2023-02-19

    摘要: Recent studies illustrate the correlation between the angular momenta of cosmic structures and their Lagrangian properties. However, only baryons are observable and it is unclear whether they reliably trace the cosmic angular momenta. We study the Lagrangian mass distribution, spin correlation, and predictability of dark matter, gas, and stellar components of galaxy-halo systems using IllustrisTNG, and show that the primordial segregations between components are typically small. Their protoshapes are also similar in terms of the statistics of moment of inertia tensors. Under the common gravitational potential they are expected to exert the same tidal torque and the strong spin correlations are not destroyed by the nonlinear evolution and complicated baryonic effects, as confirmed by the high-resolution hydrodynamic simulations. We further show that their late-time angular momenta traced by total gas, stars, or the central galaxies, can be reliably reconstructed by the initial perturbations. These results suggest that baryonic angular momenta can potentially be used in reconstructing the parameters and models related to the initial perturbations.

  • Spin conservation of cosmic filaments

    分类: 天文学 >> 天文学 提交时间: 2023-02-19

    摘要: Cosmic filaments are the largest collapsing structure in the Universe. Recently both observations and simulations inferred that cosmic filaments have coherent angular momenta (spins). Here we use filament finders to identify the filamentary structures in cosmological simulations and study their physical origins, which are well described by the primordial tidal torque of their Lagrangian counterpart regions -- protofilaments. This initial angular momenta statistically preserve their directions to low redshifts. We further show that a spin reconstruction method can predict the spins of filaments and potentially relate their spins to the initial conditions of the Universe. This correlation provides a new way of constraining and obtaining additional information of the initial perturbations of the Universe.

  • Baryonic Effects on Lagrangian Clustering and Angular Momentum Reconstruction

    分类: 天文学 >> 天文学 提交时间: 2023-02-19

    摘要: Recent studies illustrate the correlation between the angular momenta of cosmic structures and their Lagrangian properties. However, only baryons are observable and it is unclear whether they reliably trace the cosmic angular momenta. We study the Lagrangian mass distribution, spin correlation, and predictability of dark matter, gas, and stellar components of galaxy-halo systems using IllustrisTNG, and show that the primordial segregations between components are typically small. Their protoshapes are also similar in terms of the statistics of moment of inertia tensors. Under the common gravitational potential they are expected to exert the same tidal torque and the strong spin correlations are not destroyed by the nonlinear evolution and complicated baryonic effects, as confirmed by the high-resolution hydrodynamic simulations. We further show that their late-time angular momenta traced by total gas, stars, or the central galaxies, can be reliably reconstructed by the initial perturbations. These results suggest that baryonic angular momenta can potentially be used in reconstructing the parameters and models related to the initial perturbations.

  • Exploring the influencing factors of COVID-19 vaccination willingness: A mixed-method study in China

    分类: 心理学 >> 应用心理学 提交时间: 2022-05-11

    摘要: The outbreak of COVID-19 has caused enormous damage to individuals’ normal life and society’s development. Recently, with the emergence of novel coronavirus variants, people around the world are still under the attack of COVID-19. And vaccine uptake is considered one of the most effective methods to defend against this epidemic. However, many people hold hesitant attitudes towards the COVID-19 vaccine. For the vaccination promotion work, it is important to find out what factors would influence the intention of vaccination. With the aim of practical use, this study identifies two main themes of this factor structure, that is, non-manipulable factors and manipulable factors. This study uses semi-structured interviews to explore the influencing factors related to vaccination willingness. For the interview results analysis, this study employs a mixed-method, which combines qualitative thematic analysis and quantitative topic modeling. The thematic analysis identifies nine key factors and topic modeling identifies seven key factors. After gathering and discussing these key factors, this study confirmed ten key factors as final factors. More specifically, non-manipulable factors contain Effectiveness and safety of vaccines and Vaccine feasibility, and manipulable factors include Convenience of vaccine, Responsibility, External reference, Necessity and urgency of vaccination uptake, Perceived threat, Perceived benefits, Scientific and objective expression, and Policy requirement. This study investigates key influencing factors that would affect public vaccination intentions in China and provides specific guidelines for vaccination promotion for authorities and public health workers.