Vaccination is one of the most cost-effective and simplest interventions for protecting against infectious-disease epidemics. The COVID-19 (coronavirus disease 2019) outbreak in China demonstrated that physical protection and social isolation are critical to controlling an epidemic in the absence of vaccines or antiviral drugs. Considering isolation and pulse vaccination of the susceptible population subject to a delay in acquiring immunity, we propose a susceptible-infectious-recovered (SIR) model incorporating these features. Using the theory of impulsive differential equations and comparison theorems, we prove that the infection-free periodic solution $(\widetilde{S(t)},0)$ of system $(3.... More >

(1) Objective: This study aims to examine the relationships between college students' cell phone addiction, anxiety, and depression, and to explore the mediating role of anxiety in the association between cell phone addiction and depression. (2) Methods: Data were statistically analyzed using SPSS and AMOS. Independent samples t-tests and F-tests were employed to analyze differences in cell phone addiction (and its dimensions) across demographic variables. Pearson correlation analysis was conducted to assess the relationships among cell phone addiction, anxiety, and depression. Structural equation modeling (SEM) via AMOS was used to validate the hypothetical model, and regression analysis co... More >

Presents the introductory editorial for this issue of the publication. More >