• Journal of Preventive Medicine and Public Health
• /
• v.54 no.6
• /
• pp.395-403
• /
• 2021

Objectives: Previous studies have shown that participation in social activities (SA) can prevent cognitive decline (CD) and that living arrangements (LA) can affect cognitive function. This study aimed to evaluate the effects of SA and LA on CD, as well as their interactions, using longitudinal data. Methods: Data were used from the 2006-2018 Korean Longitudinal Study for Aging, which followed 10 254 adults older than 45 years over a 12-year period. CD was defined as a ≥4-point score decrease in the Mini-Mental Status Exam over 2 years. We developed an extended Cox proportional hazards model for time-dependent covariates to estimate the hazard ratio (HR) of CD in 4 groups: (1) socially active and living with others, (2) socially active and living alone, (3) socially inactive and living with others (SILO), and (4) socially inactive and living alone (SILA). The model was stratified by gender and adjusted for important confounders. Results: The HR of CD was significantly higher in the SILO group in men (HR,1.36; 95% confidence interval [CI], 1.08 to 1.78) and in the SILA group in women (HR, 1.72; 95% CI, 1.08 to 2.75). However, the interaction term for gender was not significant. Conclusions: Among socially inactive elderly adults, the HR of CD was elevated in men who lived with others and in women who lived alone, although the interaction term for gender was not significant. Socially inactive men who live with others and socially inactive women who live alone are particularly encouraged to participate in SA to prevent CD.

• The Journal of the Convergence on Culture Technology
• /
• v.8 no.2
• /
• pp.315-319
• /
• 2022

This study investigates longitudinal writing development in terms of syntactic complexity using linear mixed effects (LME) model. This study employs essays written by four case study participants. Participants voluntarily wrote essays outside of the classroom and submitted the first and second drafts, after reflecting on the automated writing evaluation feedback (i.e., Criterion) every month over one year. A total of 48 first drafts were analyzed and syntactic complexity features were selected from Syntactic Complexity Analyzer. Results of LME showed that there was a significant positive linear relationship between time and mean length of T-unit and also between time and the ratio of dependent clauses to independent clauses, indicating that case study participants wrote longer T-units and also a higher proportion of dependent clauses over one year.

• Animal Bioscience
• /
• v.36 no.11
• /
• pp.1727-1737
• /
• 2023

Objective: The poultry industry is a primary source of animal protein worldwide. The gut microbiota of poultry birds, such as chickens and ducks, is critical in maintaining their health, growth, and productivity. This study aimed to identify longitudinal changes in the gut microbiota of laying hens from birth to the pre-laying stage. Methods: From a total of 80 Hy-Line Brown laying hens, birds were selected based on weight at equal intervals to collect feces (n = 20 per growth) and ileal contents (n = 10 per growth) for each growth stage (days 10, 21, 58, and 101). The V4 regions of the 16S rRNA gene were amplified after extracting DNA from feces and ileal contents. Amplicon sequencing was performed using Illumina, followed by analysis. Results: Microbial diversity increased with growth stages, regardless of sampling sites. Microbial community analysis indicated that Firmicutes, Proteobacteria, and Bacteroidetes were the dominant phyla in the feces and ileal. The abundance of Lactobacillus was highest on day 10, and that of Escherichia-shigella was higher on day 21 than those at the other stages at the genus level (for the feces and ileal contents; p<0.05). Furthermore, Turicibacter was the most abundant genus after changing feed (for the feces and ileal contents; p<0.05). The fecal Ruminococcus torques and ileal Lysinibacillus were negatively correlated with the body weights of chickens (p<0.05). Conclusion: The gut microbiota of laying hens changes during the four growth stages, and interactions between microbiota and feed may be present. Our findings provide valuable data for understanding the gut microbiota of laying hens at various growth stages and future applied studies.

• Korean Journal of Human Ecology
• /
• v.23 no.6
• /
• pp.969-980
• /
• 2014

This paper reports on a study that examined the longitudinal and concurrent effects of the home literacy environment(HLE) on first grade language performance, and the effect of language performance on school adjustment. Study subjects were 469 first graders of 6 elementary schools. The parents' and teacher's reports were used to investigate the subjects' language performance, school adjustment, and the HLE before and after the elementary school entry. Findings from the study show that there is an association between the HLE during the preschool period and the HLE in first grade, and the HLE in first grade positively affects children's language performance. Also the children's language performance had a positive influence on their school adjustment. Therefore, it can be concluded that the HLE during the preschool period is a significant feature that lingers to affect children's language performance and school adjustment.

• Journal of Korean Academy of Nursing Administration
• /
• v.15 no.3
• /
• pp.305-313
• /
• 2009

Purpose: This study was done to identify the current status of burnout research on Korean nurses and to suggest the directions for future research. Method: Fifty two articles between 1998 and 2007 were selected using the key words such as "Nurse" and "Burnout" from the database (RISS4U et al.). Results: 77.9% of studies were master's theses unpublished in the nursing journals. All studies were cross-sectional and therefore did not allow casual inference. Hospital nurses were the most common subjects (21 studies). The most frequently used burnout measurement instrument was the Burnout Measure, while the Maslach Burnout Inventory was used in only 6 studies. 55.7% of studies reported the average burnout score as higher than the middle level. Among individual factors, variables significantly correlated to burnout were age, position, work experience, coping, and personality. Some of job factors including shift work, workloads, job stress, and organizational commitment were also significantly related to burnout. There was very little discussion about the influence of organizational factors analyzed by unit or institution level. Conclusion: In Korea, the next phase of nurse burnout research needs to consider the measurement tool selection for the international comparison and longitudinal design to find more specific causal relationships.

• The Korean Journal of Applied Statistics
• /
• v.18 no.1
• /
• pp.15-26
• /
• 2005

This study compares the difference of academic achievements for college students who entered a school with different selection criteria, and it was based on the entrance data for Hankuk University of Foreign Studies during 2000-2003. The results of this research can be used as an evidence or a supporting material for the future entrance policies or strategies in other universities.

• Journal of The Korean Society of Integrative Medicine
• /
• v.11 no.3
• /
• pp.185-194
• /
• 2023

Purpose : This study aimed to investigate the relationship between the characteristics of hemodialysis patients and the occurrence of sarcopenia through a comprehensive literature review. Methods : A systematic literature search was conducted to identify eligible studies in the Cochrane library, PubMed and Embase. In this review, we included all papers published since the initiative's inception and summarized results as of december 2022. Studies that investigated association between sarcopenia diagnosis and hemodialysis patients (aged≥18 years) were included. Ultimately, 16 studies met our selection criteria. The risk of bias was assessed using the Newcastle-Ottawa scale. Results : Fourteen of the sixteen studies (88 %) reported that significant association between sarcopenia diagnosis and hemodialysis patients. However, two studies reported no association between sarcopenia diagnosis and hemodialysis patients. As a factor statistically related to sarcopenia in hemodialysis patients, Mortality (6 studies, 38 %), age (5 studies, 31 %), body composition (4 studies, 25 %), physical activity (2 studies, 13 %), diabetes (2 studies, 13 %), cardiovascular abnormalities (1 studies, 6 %), nutritional status (3 studies, 19 %), and gender (3 studies, 19 %). Conclusion : Our findings highlight the necessity of developing a physical therapy program that accurately reflects the health status of hemodialysis patients. To further investigate the association between the diagnosis of sarcopenia and hemodialysis patients, it is recommended to conduct large-scale longitudinal studies using standardized diagnostic criteria and evaluation methods, as well as analyze potential risk factors. Consequently, this study emphasizes the importance and potential of developing physical therapy programs that effectively address the health consequences associated with hemodialysis. The significance of this research lies in its ability to provide valuable insights and lay the foundation for future studies focused on developing preventive and therapeutic interventions targeting muscle wasting syndrome resulting from hemodialysis.

• Steel and Composite Structures
• /
• v.37 no.3
• /
• pp.371-390
• /
• 2020

One of the most common strategies for retrofitting as-built reinforced concrete (RC) columns is to enlarge the existing section through the application of a new concrete layer reinforced by both steel transverse and longitudinal reinforcements. The present study was dedicated to developing a comprehensive model to predict the seismic behavior of as-built RC jacketed columns. For this purpose, a new sectional model was developed to perform moment-curvature analysis coupled by the plastic hinge method. In this analysis-oriented model, new methodologies were suggested to address the impacts of axial, flexural and shear mechanisms, variable confining pressure, eccentric loading, longitudinal bar buckling, and varying axial load. To consider the effective interaction between core and jacket, the monolithic factor approach was adopted to extent the response of the monolithic columns to that of a respective RC jacket strengthened column. Next, parametric studies were implemented to examine the effectiveness of the main parameters of the RC jacket strategy in retrofitting as-built RC columns. Ultimately, the reliability of the developed analytical model was validated against a series of experimental results of as-built and retrofitted RC columns.

• Steel and Composite Structures
• /
• v.18 no.4
• /
• pp.811-831
• /
• 2015

This paper focuses on the strengthening methods used for improving the compression behaviors of perforated box-section walls as provided in the anchorage zones of steel pylons. Rectangular plates containing double-row continuous elliptical holes are investigated by employing the boundary condition of simple supporting on four edges in the out-of-plane direction of plate. Two types of strengthening stiffeners, named flat stiffener (FS) and longitudinal stiffener (LS), are considered. Uniaxial compression tests are first conducted for 18 specimens, of which 5 are unstrengthened plates and 13 are strengthened plates. The mechanical behaviors such as stress concentration, out-of-plane deformation, failure pattern, and elasto-plastic ultimate strength are experimentally investigated. Finite element (FE) models are also developed to predict the ultimate strengths of plates with various dimensions. The results of FE analysis are validated by test data. The influences of non-dimensional parameters including plate aspect ratio, hole spacing, hole width, stiffener slenderness ratio, as well as stiffener thickness on the ultimate strengths are illustrated on the basis of numerous parametric studies. Comparison of strengthening efficiency shows that the continuous longitudinal stiffener is the best strengthening method for such perforated plates. The simplified formulas used for estimating the compression strengths of strengthened plates are finally proposed.

• Journal of the Korean Wood Science and Technology
• /
• v.44 no.5
• /
• pp.726-735
• /
• 2016

This study was carried out to evaluate the high-temperature drying characteristics of douglas-fir, hemlock, and radiata pine square timber with dimensions of thickness 15 cm and 18 cm. As a result, radiata pine showed the lowest final moisture content followed by douglas-fir and hemlock without reference to the timber size. Moreover, when the longitudinal kerfing is processed, the final moisture content was lower than control. The kerfing treatment was effective to decreasing the twist of radiata pine and hemlock. When douglas-fir is processed to the shape like the edge-grained timber that does not include the pith, the decrease of drying defect was possible.