• International Journal of Human Ecology
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• v.16 no.2
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• pp.45-61
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• 2015

This study examines the effects of time spent with parents and peers on generational differences in children's externalizing behavior problems in immigrant families. Using the Child Development Supplement and Time Diaries from the Panel Study of Income Dynamics, we found that first and second generation children exhibited fewer externalizing behavior problems than did third generation children, despite their lower socioeconomic status. First and second generation children spent more time with either one or both parents, and less time with peers, on the weekend day than did third generation children. We found a marginal but beneficial effect of time spent with fathers on the weekday, but not on the weekend day. The implications are that time spent with fathers on weekdays differs from time spent with fathers on the weekend, and that promoting immigrant father involvement on the weekday through school or community programs could benefit immigrant children.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.583-584
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• 2015

In this paper, the numerical results concerning different orbits of a 3D axisymmetric non-rotating galactic potential are presented. We use $Paczy{\acute{n}}ski^{\prime}s$ gravitational potential with different birth velocity distributions for the isolated old Neutron Star (NS) population. We note some smooth non-constant segments corresponding to regular orbits as well as the characterization of their chaoticity. This is strongly related to the effect of different kick velocities due to supernovae mass-loss and natal kicks to the newly-formed NS. We further confirm that the dynamical motion of the isolated old NSs in the gravitational field becomes obvious, with some significant diffraction in the symmetry of their orbital characteristics.

• Bulletin of the Korean Chemical Society
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• v.26 no.10
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• pp.1505-1511
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• 2005

The excitation energy transfer process occurring in energy donor-acceptor linked porphyrin array system is theoretically simulated using the on-the-fly filtered propagator path integral method. The compound consists of an energy donating meso-meso linked Zn(II) porphyrin array and an energy accepting 5,15-bisphenylethynylated Zn(II) porphyrin, in which the donor array and the acceptor are linked via a 1,4-phenylene spacer. Real-time path integral simulations provide time-evolution of the site population and the excitation energy transfer rate constants are determined. Simulations and experiments show an excellent agreement indicating that the path integration is a useful tool to investigate the energy transfer dynamics in molecular assemblies.

• Animal cells and systems
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• v.2 no.2
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• pp.209-216
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• 1998

The invasion of Ambrosia artemisiifolia in the Ukrainian Carpathians Mts. and the Transcarpathian Plain in Central Europe was reconstructed on the basis of floristic records. The first spontaneous occurrence was dated from the beginning of the 1940s. Within the next 55 year period, the distributional spread speed of the species was of 67.6 $km^2/y$ (by the average data). The occupied area by A. artemisiifolia in the range of the studied areas is about $3716.5km^2$ now. The features of behavior of the invader and the habitat preference were determined. The frequency of occurrence by sociologic-ecological classification was carried out. The generalized model of correlations among the gravitation, the active temperature sum and the disturbance gradients and the frequency of occurrence of the species was presented. The scheme of the invasion stages of A. artemisiifolia is reflected in the population status changes of the species during the areal dynamics.

• Animal Systematics, Evolution and Diversity
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• v.19 no.1
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• pp.11-17
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• 2003

In the study of population dynamics of non-biting midges (Diptera: Chironomidae) emerging from reclaimed rice fields in Seosan, Chungchongnam-do, Korea, a new species, Tanytarsus seosanensis sp. nov. and an unrecorded species from Korea, Chironomus javonus (Kieffer) were found. T.seosonensis was the third dominant species among the non-biting midges found in the reclaimed rice fields, whereas C.javanus was a rare species. They are fully described with illustrations.

• The Pure and Applied Mathematics
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• v.15 no.3
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• pp.329-342
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• 2008

There have been many experimental and observational evidences which indicate the predator response to prey density needs not always monotone increasing as in the classical predator-prey models in population dynamics. Holling type functional response depicts situations in which sufficiently large number of the prey species increases their ability to defend or disguise themselves from the predator. In this paper we investigated the stability and instability property for a Holling type predator-prey system of a generalized form. Hopf type bifurcation properties of the non-diffusive system and the diffusion effects on instability and bifurcation values are studied.

• Bulletin of the Korean Chemical Society
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• v.17 no.12
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• pp.1112-1117
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• 1996

The electronic structures of twenty-seven isomers of a macrocyclic fulleropyrrolidine are investigated with semi-empirical extended Huckel (EH) molecular orbital method. The geometry of each isomer is determined by the molecular mechanics and dynamics methods based on UFF (universal force field) empirical force field. The calculated geometries, such as the carbon-carbon distances of the fullerene moiety, are in good agreement with those of related fullerene derivatives. The EH calculation shows that the formation of macrocyclic pyrrolidine ring on fullerene moiety results in the reduction of the HOMO-LUMO energy gap. From the graphical analysis of the DOS (density of states), PDOS (projected DOS), and MOOP (molecular orbital overlap population) curves, we can find that this reduction is due to splitting of the HOMO of fullerene moiety, which results from the symmetry-breaking and the distortion of the buckminsterfullerene framework from its ideal icosahedral structure.

• Plant Journal
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• v.4 no.4
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• pp.62-70
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• 2008

PGV(Plasma Gasification & Vitrification) system has been developed based on a pyrolysis melting gasification technology that provides the possibilities of acquiring renewable energy. As volume of wastes increases with the rapid industrialization and population growth, eco friendly disposal is drawing more social attention. Pyrolysis plasma technology is regarded as the best environmentally friendly process for the waste disposal among numerous waste disposal processes. Introduced in this paper is the behavior of the plasma torch and a computational fluid simulation dynamics is discussed for designing the melting furnace. Some PGV applications have also been discussed.

• BMB Reports
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• v.55 no.4
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• pp.166-174
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• 2022

Hepatic macrophages are key immune cells associated with the broad ranges of liver diseases including steatosis, inflammation and fibrosis. Hepatic macrophages interact with other immune cells and orchestrate hepatic immune circumstances. Recently, the heterogenous populations of hepatic macrophages have been discovered termed residential Kupffer cells and monocyte-derived macrophages, and identified their distinct population dynamics during the progression of various liver diseases. Liver injury lead to Kupffer cells activation with induction of inflammatory cytokines and chemokines, which triggers recruitment of inflammatory monocyte-derived macrophages. To understand liver pathology, the functions of different subtypes of liver macrophages should be regarded with different perspectives. In this review, we summarize recent advances in the roles of hepatic macrophages under liver damages and suggest hepatic macrophages as promising therapeutic targets for treating liver diseases.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.27 no.4
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• pp.281-295
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• 2023

This study aims to establish and analyze a mathematical model for the transmission dynamics of male adolescent smoking and to determine an optimal control strategy to reduce male adolescent smoking. We consider three groups in the population: smokers, non-smokers, and temporary nonsmokers. In our model to which optimal control theory was applied, the number of smokers decreased sharply and the number of non-smokers increased significantly. Our simulation results under various control scenarios reveal that integrated control measures(such as prevention, education, and treatment) may be necessary to reduce the growth rate of adolescent smoking. Moreover, we concluded that efforts to encourage current smokers and temporary quitters to quit should be sustained longer than efforts to reduce the rate at which nonsmokers become smokers through smoking prevention education.