Developmental trajectories of tobacco use and risk factors from adolescence to emerging young adulthood: a population-based panel study

Abstract Background Adolescence to young adulthood is a critical developmental period that determines lifelong patterns of tobacco use. We examined the longitudinal trajectories of tobacco use, and risk factors for its use, and explored the association between the trajectories of mobile phone dependency and smoking throughout the life-course among adolescents and young adults. Methods Data of 1,723 subjects (853 boys and 870 girls) were obtained from six waves of the Korean Children and Youth Panel Survey (mean age = 13.9–19.9years). To identify trajectories of smoking and mobile phone dependency, group-based trajectory modelling (GBTM) was conducted. A multinomial logistic regression analysis was performed to identify the characteristics of the trajectory groups. Results GBTM identified four distinct smoking trajectories: never smokers (69.1%), persistent light smokers (8.7%), early established smokers (12.0%), and late escalators (10.3%). Successful school adjustment decreased the risk of being an early established smoker (odds ratio [OR] 0.46, 95% confidence interval [CI] 0.27–0.78). The number of days not supervised by a guardian after school was positively associated with the risk of being an early established smoker (OR 1.96, 95% CI 1.23–3.13). Dependency on mobile phones throughout the life-course was positively associated with the risk of being a persistent light smoker (OR 4.04, 95% CI 1.32–12.34) or early established smoker (OR 8.18, 95% CI 4.04–16.56). Conclusions Based on the group-based modeling approach, we identified four distinctive smoking trajectories and highlight the long-term effects of mobile phone dependency, from early adolescence to young adulthood, on smoking patterns

Study of the effect of nano-sized precipitates on the mechanical properties of boron-added low-carbon steels by neutron scattering techniques

The effect of nano-sized precipitates on the mechanical properties of boron-added low-carbon steels was studied by neutron scattering techniques such as powder diffraction, small-angle scattering and particle tracking autography

Future Constraints on Dark Matter with Gravitationally Lensed Fast Radio Bursts Detected by BURSTT

Understanding dark matter is one of the most urgent questions in modern physics. A very interesting candidate is primordial black holes (PBHs; Carr2016). For the mass ranges of $100 M_{\odot}$, PBHs have been ruled out. However, they are still poorly constrained in the mass ranges of $10^{-16} - 100 M_{\odot}$ (Belotsky et al. 2019). Fast radio bursts (FRBs) are millisecond flashes of radio light of unknown origin mostly from outside the Milky Way. Due to their short timescales, gravitationally lensed FRBs, which are yet to be detected, have been proposed as a useful probe for constraining the presence of PBHs in the mass window of $< 100M_{\odot}$ (Mu\~noz et al. 2016). Up to now, the most successful project in finding FRBs has been CHIME. Due to its large field of view (FoV), CHIME is detecting at least 600 FRBs since 2018. However, none of them is confirmed to be gravitationally lensed (Leung et al. 2022). Taiwan plans to build a new telescope, BURSTT dedicated to detecting FRBs. Its survey area will be 25 times greater than CHIME. BURSTT can localize all of these FRBs through very-long-baseline interferometry (VLBI). We estimate the probability to find gravitationally lensed FRBs, based on the scaled redshift distribution from the latest CHIME catalog and the lensing probability function from Mu\~noz et al. (2016). BURSTT-2048 can detect ~ 24 lensed FRBs out of ~ 1,700 FRBs per annum. With BURSTT's ability to detect nanosecond FRBs, we can constrain PBHs to form a part of dark matter down to $10^{-4}M_{\odot}$.Comment: Accepted for publication in ApJ. A summary video is available at this https://youtu.be/yivrtvuMDH

Modified embedded-atom method interatomic potentials for the Mg-Al alloy system

We developed new modified embedded-atom method (MEAM) interatomic potentials for the Mg-Al alloy system using a first-principles method based on density functional theory (DFT). The materials parameters, such as the cohesive energy, equilibrium atomic volume, and bulk modulus, were used to determine the MEAM parameters. Face-centered cubic, hexagonal close packed, and cubic rock salt structures were used as the reference structures for Al, Mg, and MgAl, respectively. The applicability of the new MEAM potentials to atomistic simulations for investigating Mg-Al alloys was demonstrated by performing simulations on Mg and Al atoms in a variety of geometries. The new MEAM potentials were used to calculate the adsorption energies of Al and Mg atoms on Al (111) and Mg (0001) surfaces. The formation energies and geometries of various point defects, such as vacancies, interstitial defects and substitutional defects, were also calculated. We found that the new MEAM potentials give a better overall agreement with DFT calculations and experiments when compared against the previously published MEAM potentials.Comment: Fixed a referenc