The nonlinear propagation of dust-ion-acoustic (DIA) waves in a dusty plasma containing trapped electrons following vortex-like distribution, cold mobile ions, and arbitrarily charged static dust is theoretically investigated. The properties of small but finite amplitude DIA solitary waves (SWs) are studied by employing the reductive perturbation technique. It is found that owing to the departure from the Maxwellian electron distribution to a vortex-like one, the dynamics of such DIA SWs is governed by a modified Korteweg-de Vries equation. The basic features (amplitude, width, speed, etc.) of such DIA SWs, which are found to be significantly modified by the vortex-like electron distribution and dust polarity, are also examined. The implications of our results to space and laboratory dusty plasmas are briefly discussed.

A theoretical investigation has been made on obliquely propagating dust-ion-acoustic solitary waves (DIASWs) in magnetized dusty electronegative plasma containing Boltzmann electrons, trapped negative ions, cold mobile positive ions, and arbitrarily charged stationary dust. The reductive perturbation method has been employed to derive the modified Zakharov-Kuznetsov (MZK) equation which admits solitary wave solution under certain conditions. The multi-dimensional instability of these solitary waves is also studied by the small-k (long wavelength plane wave) perturbation-expansion technique. The basic properties (speed, amplitude, width, instability, etc.) of small but finite amplitude DIASWs are significantly modified by the effects of external magnetic field, obliqueness, polarity of dust, and trapped negative ions. The implications of our results in space and laboratory plasmas are briefly discussed.

BackgroundThe global effort to develop herd immunity in the general public against the COVID-19 pandemic is currently ongoing. However, to the best of our knowledge, there have been no studies on how the COVID-19 vaccine affects mental health in the context of the COVID-19 pandemic in Bangladesh. The present study investigated the psychological effects and associated factors among vaccinated and unvaccinated general populations against COVID-19 infection in Bangladesh.MethodsA nationwide online cross-sectional survey was conducted in Bangladesh from June 23 to December 25, 2021. The frequency of symptoms of psychological distress, depression, anxiety, stress, post-traumatic stress disorder (PTSD), insomnia, and fear was assessed using the Bangla versions of the GHQ-12, PHQ-2, GAD-2, PSS-4, PC-PTSD-5, ISI, and FCV-19S scales, respectively.ResultsThe study included 3,013 persons from all eight divisions of Bangladesh, with 1,272 (42.2%) being vaccinated and 1,741 (57.8%) being unvaccinated. Compared with unvaccinated populations, vaccinated populations had significantly lower prevalence rates of psychological distress (36.4 vs. 51.5%), depression (21.1 vs. 37.9%), anxiety (25.1 vs. 44.9%), stress (19.4 vs. 30.4%), PTSD (29.4 vs. 38.3%), insomnia (18.7 vs. 39.4%), and fear symptoms (16.1 vs. 27.5%). Among vaccinated populations, respondents who lived in nuclear families were significantly associated with higher risk of psychological distress (AOR, 1.38; 95% CI, 1.09–1.78), depression (AOR, 1.49; 95% CI, 1.11–1.98), anxiety (AOR, 1.77; 95% CI, 1.21–1.98), and fear (AOR, 1.43; 95% CI, 1.11–1.83) symptoms. Participants who lost family members, friends, or colleagues due to the COVID-19 pandemic had significantly higher risk of symptoms of psychological distress (AOR, 1.35; 95% CI, 1.02–1.79), anxiety (AOR, 1.41; 95% CI, 1.11–1.87), and PTSD (AOR, 1.76; 95% CI, 1.24–2.19). On the other hand, unvaccinated populations who lived in the Dhaka division were significantly associated with an increased risk of depression (AOR, 2.06; 95% CI, 1.40–2.52), anxiety (AOR, 1.86; 95% CI, 1.15–2.47), stress (AOR, 1.92; 95% CI, 1.12–2.88), and insomnia (AOR, 1.88; 95% CI, 1.20–2.94) symptoms. Except for PTSD and fear symptoms, unemployed participants had considerably higher rates of psychological distress, depression, anxiety, stress, and insomnia symptoms (e.g., psychological distress: AOR, 1.83; 95% CI, 1.10–2.62; depression: AOR, 1.74; 95% CI, 1.37–2.19).ConclusionsThis study recommends immunizing unvaccinated populations as soon as possible to prevent infection and boost mental health. Vulnerable people needed special care, health-related education, and psychological assistance.

An attempt has been made to study the multidimensional instability of dust-ion-acoustic (DIA) solitary waves (SWs) in magnetized multi-ion plasmas containing opposite polarity ions, opposite polarity dusts and nonthermal electrons. First of all, we have derived ZakharovKuznetsov (ZK) equation to study the DIA SWs in this case using reductive perturbation method as well as its solution. Small-k perturbation technique was employed to find out the instability criterion and growth rate of such a wave which can give a guideline in understanding the space and laboratory plasmas, situated in the D-region of the Earth's ionosphere, mesosphere, and solar photosphere, as well as the microelectronics plasma processing reactors.

The nonlinear propagation of dust-acoustic (DA) solitary waves in three-component unmagnetized dusty plasma consisting of Maxwellian electrons, vortex-like (trapped) ions, and arbitrarily charged cold mobile dust grain has been investigated. It has been found that, owing to the departure from the Maxwellian ions distribution to a vortex-like one, the dynamics of small but finite amplitude DA waves is governed by a nonlinear equation of modified Korteweg-de Vries (mK-dV) type instead of K-dV. The reductive perturbation method has been employed to study the basic features (phase speed, amplitude, width, etc.) of DA solitary waves which are significantly modified by the presence of trapped ions. The implications of our results in space and laboratory plasmas are briefly discussed.