• Animal Bioscience
• /
• 제36권11호
• /
• 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.

• 한국생활과학회지
• /
• 제23권6호
• /
• 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.

• 간호행정학회지
• /
• 제15권3호
• /
• 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.

• 응용통계연구
• /
• 제18권1호
• /
• pp.15-26
• /
• 2005

본 연구는 2000년-2003년에 이르는 한국외국어대학교의 입시자료를 토대로, 입시전형방법에 따른 신입생의 입학 후 학업성취도를 비교하고 있다. 이 연구의 결과는 현재 각 대학마다 행하고 있는 여러 가지 입시전형들에 대한 재평가 및 모집인원의 변경 등에 필요한 기초 자료가 될 수 있을 것으로 사료된다.

• 대한통합의학회지
• /
• 제11권3호
• /
• 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
• /
• 제37권3호
• /
• 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
• /
• 제18권4호
• /
• 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
• /
• 제44권5호
• /
• pp.726-735
• /
• 2016

본 연구는 두께 15 cm와 18 cm 크기 Douglas-fir, Hemlock, Radiata pine 정각재의 고온건조 특성을 평가하기 위해 수행되었다. 수종에 따른 최종함수율은 시험재의 두께에 관계없이 Radiata pine, Douglas-fir, Hemlock 순으로 Radiata pine에서 가장 낮았으며, 배할처리를 하였을 때 무처리재보다 낮은 함수율을 나타내었다. Radiata pine과 Hemlock의 경우 배할처리를 하였을 때 함수율과 뒤틀림 발생을 감소시키는 효과가 있는 것으로 나타났다. Douglas-fir는 수를 포함하지 않는 정목형태로 가공될 때 건조결함의 감소가 가능하였다.

• 대한간호학회지
• /
• 제33권6호
• /
• pp.820-828
• /
• 2003

Purpose: In this longitudinal study, we examined the moral judgment level and its related factors, such as individual characteristics. The result of this study will provide baseline data to establish policy of ethics education for college students and healthcare professionals. Method: We enrolled 37 nursing students and 20 medical students as the subjects in a university in Suwon, Korea. We conducted a questionnaire on the subjects using Korean version of Defining Issues Test(DIT) to analyze the subjects' moral judgment level. Collected data was coded using ASCII document and scored using Fortran program for computer. Then the data was statistically analyzed by SPSS Version 10.0. Result: Nursing students' moral development score at each stage were consistently higher at stage 5A across 4-years rather than other stages. On the other hand, medical students' moral development score were consistently higher at stage 4 than other stages. There was no significant difference in the change P(%) score at each academic year in both groups. In the perspective of the subjects' general characteristics, P(%) score showed no significant in both groups. Conclusion: Based on the results of this study, further studies will examine the correlation between curriculum and moral judgment development in detail. Moreover, we suggest that the current ethics education should be developed and evaluated in more realistic manner.

• Journal of Mechanical Science and Technology
• /
• 제20권12호
• /
• pp.2105-2114
• /
• 2006

In this paper, a simplified model is studied to predict analytically the vibration from the helical gear system due to an axial excitation of helical gears. The simplified model describes gear, shaft, bearing, and housing. In order to obtain the axial force of helical gears, the mesh stiffness is calculated in the load deflection relation. The axial force is obtained from the solution of the equation of motion, using the mesh stiffness. It is used as a longitudinal excitation of the shaft, which in turn drives the gear housing through the bearing. In this study, the shaft is modeled as a rod, while the bearing is modeled as a parallel spring and damper only supporting longitudinal forces. The gear housing is modeled as a clamped circular plate with viscous damping. For the modeling of this system, transfer matrices for the rod and bearing are used, using a spectral method with four pole parameters. The model is validated by finite element analysis. Using the model, parameter studies are carried out. As a result, the linearized dynamic shaft force due to the gear excitation in the frequency domain was proposed. Out-of-plan displacement from the forced vibrating circular plate and the renewed mode normalization constant of the circular plate were also proposed. In order to control the axial vibration of the helical gear system, the plate was more important than the shaft and the bearing. Finally, the effect of the dominant design parameters for the gear system can be investigated by this model.