• 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.

• The korean journal of orthodontics
• /
• v.19 no.1 s.27
• /
• pp.137-151
• /
• 1989

To help arrive at a more accurate diagnosis of anteroposterior apial base relationship on each individual case, it is important to compare the interpretation in the same population on a longitudinal basis. The author studied on the changes of the anteroposterior apical base relationship using serial lateral cephalometric roentgenograms of 15 boys and 27 girls aged from 6 to 13 years of Korean children. Following results were obtained 1. Norms of Korean boys and girls were established. 2. With ages, there was a gradual decrease of ANB, AXB angle, and there was a gradual increase of facial angle, A-B plane angle, APDI. 3. Wits appraisal does not change significantly with ages. 4. No significant differences were observed in the changes between male and female subjects for all absolute values between the ages of 6 years and 12 years, but significant differences were observed in ANB, AXB, A-B plane angle of the age of 13 years. No significant differences were observed in the changes between male and female subjects for all incremental values between the ages of 6 years and 13 years.

• The korean journal of orthodontics
• /
• v.14 no.2
• /
• pp.217-231
• /
• 1984

Many investigators have studied the growth changes of craniofacial complex to obtain important informations and standard values with which attempts at prediction of growth and treatment results have been under exploration. The author analyzed 360 cephalometric roentgenograms of 40 boys and 50 girls taken from the ages of 6 to 9 to assess the growth changes of craniofacial complex and to establish Korean norms by Ricketts' analysis method. 17 Landmarks, 10 planes and 8 angles were plotted and measured by linearly and angularly. The results were as follows: 1. The author made the tables of means, standard deviations from the measured values. 2. The item which showed significant difference between males and females in longitudinal study was facial axis length. 3. Items which show significant changes during 3 years were cranial base length, facial axis length, lower incisor to APO, Upper molar to PTV in males, and cranial base length, facial axis length, upper molar to PTV in females. 4. The correlations between cranial base length and facial axis length to body height and weight were higher in males than in females throughout the items.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.3 no.4 s.11
• /
• pp.103-109
• /
• 2003

A numerical analysis of cable-stayed bridge is conducted to determine optimum longitudinal modulus of elasticity which represents the boundary condition between the tower and main girder. The effect of longitudinal modulus of elasticity is investigated for different loading condition (live load, wind load, seismic load), respectively. There are significant changes in the member forces as variations of longitudinal modulus of elasticity, such as, $k_h$=e=100tonf/m/bearing (live load), $k_h$=e=1000tonf/m/bearing (seismic load), However, the wind loads do not affect member forces. The optimum longitudinal modulus of elasticity is determined from considering minimum member forces in the numerical analysis results.

• Journal of muscle and joint health
• /
• v.8 no.2
• /
• pp.278-286
• /
• 2001

With the aging of society a great deal of interest is being placed on the value of longitudinal data in evaluating physiological losses. We present data on test-one/test-two reliability and reproducibility for measures of training, bone density from a longitudinal study of master athletes. Fifty-two males (mean age at test $1=58.2{\pm}9.8\;years$) and thirty-two females ($54.4{\pm}8.8\;years$) were selected from the study population. Bone mineral density was determined using DEXA (Hologic 1500). The characteristics of the subjects are presented below as $means\;{\pm}\;S.D$. The data was imported into the Statistical Package for the Social Science (SPSS 9.0, Chicago, IL). Paired t-tests were performed between visit 1 and visit 2 in subjects. Pearson correlations were performed. The results of this study indicate the measures of training history, body mass and bone density are reasonably stable and reproducible. We conclude that body composition and bone density parameters are stable and reproducible over time in active older subjects. Physiologic measures in master athletes are fairly stable, and reproducible over time Longitudinal studies investigating age-related changes in master athletes need to be conducted on a time schedule of greater than two years.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.10
• /
• pp.1517-1522
• /
• 2015

Since electric railroad vehicle pass through repeatedly on the railroad bridge, the dynamic load that causes the change of tension of contact wire affect it constantly. In this paper, we measured the dynamic displacement of the railroad bridges to analyze the effect of tension in the catenary. A result of dynamic measurement of the longitudinal displacement, it's maximum value was 39.9mm which was lower than the primary management criteria 378mm. Also on the based of a maximum temperature, it shows a feature that the longitudinal displacement value increased as temperature rise from April to October. In terms of behavior characteristics of a tensioning device, it was confirmed to be the value of 50mm stroke movement when the temperature changes ±5℃.

• International Journal of Highway Engineering
• /
• v.16 no.6
• /
• pp.95-104
• /
• 2014

PURPOSES : The purpose of this study is to evaluate the degree of restraint (DOR) of longitudinal steel at continuously reinforced concrete pavement (CRCP) against environmental loadings. METHODS : To measure the longitudinal steel strain, 3-electrical resistance and self-temperature compensation gauges were installed to CRCP test section (thickness = 250mm, steel ratio = 0.7%) and continuously measured 10 min. intervals during 259 days. In order to properly analyze the steel strains first, temperature compensation process has been conducted. Secondly, measured steel strains were divided into 12 phases with different events such as before paving, during concrete hardening, and after first cracking, etc. RESULTS : Thermal strain rate (TSR) concept is defined as the linear strain variations with temperature changes and restraints rate of longitudinal steel against environmental loadings (especially thermal loading) with different cases is defined as degree of restraint(DOR). New concept of DOR could be indirect indicator of crack width behaviors of CRCP. CONCLUSIONS : Before paving, DOR of longitudinal steel is almost same at the coefficient of thermal expansion of steel ($12.44m/m/^{\circ}C$) because of no restraint boundary condition. After concrete pouring, DOR is gradually changed into -1 due to concrete stiffness developing with hydration. After first cracking at crack induced area, values of DOR are around -3~-5. The negative DOR stands for the crack width behavior instead of steel strain behavior. During winter season, DOR reached to -5.77 as the highest, but spring this values gradually reduced as -1.7 as the lowest. Based on this observation, we can presume crack width decreased over time within the time frame of this study. This finding is not consistent with the current theory on crack width variations over time, so further study is necessary to identify the causes of crack width reducing. One of the reasons could be related to concrete stress re-distribution and stress relaxation.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.5
• /
• pp.173-178
• /
• 2016

When a ballast track of a high-speed train is constructed on a bridge, the displacement of the bridge decks can occur because they are not fixed to the rails. Moreover, relative displacements occur between the bridge and rails caused by temperature changes and external loads. The current longitudinal resistance criteria (UIC Code 774-3, KR C-08080) on ballast tracks with continuous welded rails (CWRs) do not take into account the longitudinal movement of the bridge and the frictional force between the ballast and slabs. In addition, the magnitude of the longitudinal resistance, k, is calculated somewhat conservatively and, (therefore?) it acts as an unfavorable element in the design of long span and continuous railway bridges. Thus, in order to replicate the actual behavior more effectively, the longitudinal resistance of CWRs should take into account the additional rigidity between the slab and track. In this study, the longitudinal resistances of the ballasted track on the bridge were analyzed by carrying out an experimental study with a test setup designed to simulate the deck and bed track. In the test results, the maximum longitudinal resistances of the tests were similar to the resistances of the current codes, however, the measured longitudinal stiffness designed to limit the displacement of the tests were much smaller in comparison with the longitudinal stiffness on the codes.

• The Korean Journal of Community Living Science
• /
• v.17 no.3
• /
• pp.109-121
• /
• 2006

This study examines the relationship between mother's stress and cortisol level during late pregnancy and how it changes into postpartum periods. Thirty one families were recruited from Daejeon and Incheon in South Korea. The major findings were as follows: (1) The level of mothers' cortisol followed the typical diurnal pattern of decline throughout the day. Further longitudinal analysis revealed that the level of Korean mothers' cortisol steadily lowered from the 8th prenatal month to the 6th postnatal month. (2) During pregnancy, mothers reported to experience changes in physical activities, daily routines, eating habits, types or amount of social activities and sleeping habits. Among these they were stressed the most by changes in physical activities and social activities. (3) The results of postpartum depression tests conducted at two months after giving birth showed mothers at this time were mostly stressed from difficulty sleeping and unnecessary self criticism. (4) The level of psycho social stress in mothers at six months after giving birth was mainly on social roles and the questions about self reliance marked the highest points. (5) Overall, there was a tendency for the level of maternal stress to decrease definitely from before and after the delivery and even though the level of stress was steadily decreasing up to 6th postpartum month it was not as sharp as those of before and after the birth of the babies. The level of cortisol analysis also showed the same obvious tendency.

• Journal of Korean Academy of Nursing
• /
• v.45 no.5
• /
• pp.694-703
• /
• 2015

Purpose: This study was a prospective longitudinal study to identify changes in quality of life in patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT). It was based on Roy's adaptation model. Methods: The questionnaires were administered before HSCT, 30 and 100 days after HSCT. Of the 48 potentially eligible patients, 44 (91.7%) participated in the study and 40 (90.9%) completed the questionnaires at 100 days after HSCT. Multilevel analysis was applied to analyze changes in quality of life. Results: Overall, quality of life showed a decreasing tendency from pre-HSCT to 100 days after HSCT. The adaptation level of participants was compensatory. Type of conditioning was the significant factor influencing quality of life before HSCT (${\beta}_{00}$=79.92, p <.001; ${\beta}_{01}$= - 12.64, p <.001) and the change rate of quality of life (${\beta}_{10}$= - 1.66, p =.020; ${\beta}_{11}$=2.88, p =.014). Symptom severity (${\beta}_{20}$= - 1.81, p =.004), depression (${\beta}_{30}$= - 0.58, p =.001), social dependency (${\beta}_{40}$= - 0.35, p =.165), and loneliness (${\beta}_{50}$= - 0.23, p =.065) had a negative effect on changes in quality of life. Symptom severity and depression were statistically significant factors influencing changes in quality of life. Conclusion: According to the results of this study, the development of nursing intervention is needed to improve quality of life in patients undergoing allogeneic hematopoietic stem cell transplantation in the early immune reconstruction period. The interventions should include programs to enhance coping capacity and programs to help control symptom severity and depression. Also these interventions need to be started from the beginning of HSCT and a multidisciplinary approach would be helpful.