• Journal of Radiation Protection and Research
• /
• v.28 no.1
• /
• pp.9-18
• /
• 2003

Rice plants at different seed-developing stages were exposed to HTO vapor in an exposure box for 1 h during daytime and nighttime to investigate the levels of tissue free water $^3H$ (TFWT) and organically bound $^3H$ (OBT) in different plant parts. In the daytime experiment, TFWT concentrations in leaves at the end of exposure $(h_0)$ were around 100% of the 1 hour mean HTO concentrations in air moisture whereas in the nighttime experiment, they were as low as $30{\sim}40%$ of the air concentration. TFWT concentrations in both experiments decreased very rapidly in the beginning but much mote slowly later and those at harvest were hundreds to hundred thousands times lower than those at $h_0$. OBT concentrations varied with time in different manners depending on plant parts and exposure times and differed between at $h_0$ and at harvest by factors of less than 10 on the whole. Even during nighttime exposures, OBT was produced at about a third the rate for daytime exposures. The degree of the conversion of airborne HTO into OBT in mature rice seeds, being several times higher in the daytime experiment than in the nighttime experiment, was highest after the exposure peformed at the most actively seed-developing stage for both experiments. It is estimated that OBT would contribute much more to the ingestion radiation dose than TFWT if rice plants are exposed to HTO vapor for the seed-developing period.

• Korean Parent-Child Health Journal
• /
• v.2
• /
• pp.83-110
• /
• 1999

The purpose of this study was to identify the sleep/activity patterns of neonates and to provide a baseline data for the development effective mother-infant relationship. Subjects of this study were 36 newborns aged 1-21 days and stayed in Postpartum Care Center in Taejon during the period of October 28th, 1999 to February 10th, 2000. The data were collected using NCASA developed by Barnard et al. and were analyzed with SPSS 7.5 for window program. The results of this study were as follows: 1. An average day sleep of neonates was 8.0 hours, night sleep was 3.6 hours, and total sleep was 11.6 hours. A longest period of day sleep was 3.8 hours and a longest period of night sleep was 3.4 hours. The regularity of day sleep was 22.1%, night sleep was 23.3%, and total was 22.1%. 2. The frequency of daytime feeding was 6.9, nighttime fee ding was 3.4, resulting in total of 10.3. The regularity of feeding was 37.4%, and the frequency of night awakening was 2.4. 3. Associations among variables related to neonate's sleep/activity records were as follows : - The regularity of total sleep was positively correlated with the frequencies of day sleep(r=.57, P=.00), night sleep (r=.40, P=.01), and total sleep(r=.65, P=.00). - The frequency of total feeding was negatively correlated with the frequencies of day sleep(r=-.29, P=.04), night sleep(r=-.39, P=.02), and total sleep(r=-.42, P=.00), as well as longest day sleep(r=-.50, P=.00). - The regularity of feeding was negatively correlated with the frequency of night sleep(r=-.35, P=.02), longest period of day sleep(r=-.32, P=.04), and longest period of night sleep(r=-.30. P=.04), whereas positively correlated with frequencies of daytime feeding (r=.29, P=.02) and nighttime feeding (r=.32, P=.05). - The frequency of night awakening was negatively correlated with amount of night sleep(r=-.39, P=.02) and frequency of daytime feeding(r=-.42, P=.01) while positively correlated with frequencies of nighttime feeding(r=.68, P=.00) and total feeding(r=.50, P=.00). 4. Although there was no statistical significant difference between sleep pattern and infant's age, following tendency was noted: - As baby gets older, total amount of sleep and longest period of day sleep decreased while longest period of night sleep increased. - As baby gets older, the regularity of day sleep decreased while the regularity of night sleep and total sleep slightly increased. - The frequencies of daytime and total feedings increased while the frequency of nighttime feeding decreased. In conclusion, the author found that the neonates of this study showed less amount of sleep, more night awakening, and more night time feedings than NCAST sample. There was a certain sleep/activity pattern existed: If babies were fed more frequently, daytime or nighttime sleeping hours became shorter, and if babies had longer daytime sleep, frequent nighttime awakenings were noted. This pattern illustrated the significant influence of feeding and sleep periods on each other. Awakening in the night is natural and normal patterns in the newborn period. The result of this study will provide information to parents about what to expect their infants.

• Annals of Occupational and Environmental Medicine
• /
• v.35
• /
• pp.22.1-22.9
• /
• 2023

Background: Shift work increases the risk of chronic diseases, including metabolic diseases. However, studies on the relationship between shift work and renal function are limited. The aim of this study was to investigate the association between shift work and a decreased glomerular filtration rate (GFR). Methods: Data were evaluated for 1,324,930 workers who visited the Korean Medical Institute from January 1, 2016 to December 31, 2020 and underwent a health checkup. Daytime workers were randomly extracted at a ratio of 1:4 after matching for age and sex. In total, 18,190 workers aged over 40 years were included in the analyses; these included 3,638 shift workers and 14,552 daytime workers. Participants were categorized into the shift work group when they underwent a specific health checkup for night shift work or indicated that they were shift workers in the questionnaire. The odds ratio was calculated using a conditional logistic regression to investigate the relevance of shift work for changes in GFR. Results: 35 workers in the shift group and 54 in the daytime group exhibited an estimated GFR (eGFR) value of < 60 mL/min/1.73m² (p < 0.01). The difference in eGFR values between two checkups differed significantly depending on the type of work (p < 0.01); the difference in the shift work group (-9.64 mL/min/1.73 m²) was larger than that in the daytime work group (-7.45 mL/min/1.73 m²). The odds ratio for eGFR reduction to < 60 mL/min/1.73 m² in the shift group versus the daytime group was 4.07 (95% confidence interval: 2.54-6.52), which was statistically significant. Conclusions: The results of this study suggest that eGFR decreases by a significantly larger value in shift workers than in daytime workers; thus, shift work could be a contributing factor for chronic kidney disease (CKD). Further prospective studies are necessary to validate this finding and identify measures to prevent CKD in shift workers.

• Proceedings of the Korea Contents Association Conference
• /
• 2017.05a
• /
• pp.257-258
• /
• 2017

Modern society tends to bring excessive labor to people and, therefore, further health management is required. In this paper, by using the clustering technique, one of machine learning methods, we try to bring out the measure of fatigue from heart rate (HR) variation during daytime work, helping people to get high-quality of healthy and calm life.

• Journal of the Korean Chemical Society
• /
• v.13 no.4
• /
• pp.249-261
• /
• 1969

Studies of photochemical reactions of the pure oxygen atmosphere are made using reaction rate constants and atmospheric data available in the latest literature. The daytime and nighttime variations in atomic oxygen and ozone are computed, based on three different conditions: 1) photochemical equilibrium, 2) direct integrations of the rate equations with modifications and approximation to the equations, and 3) by numerical integrations. The departure from the photochemical equilibrium concentrations during day and nighttime are discussed by comparing the results obtaind from the three conditions.

• Korean Journal of Adult Nursing
• /
• v.25 no.6
• /
• pp.679-689
• /
• 2013

Purpose: This prospective study was designed to investigate the prevalence of urinary incontinence (UI), voided volume, post void residual volume (PVRV), daytime frequency and nocturia in women over 40 years. Methods: The sample comprised of 302 women over 40 years.The study lasted from February 2008 to November 2009. Data about daytime frequency and nocturia were gathered from 48 hour bladder diary. Further, a PVRV was assessed through a bladder ultrasonography. Data were analyzed using the t-test, Mann Whitney test, Kruskal Wallis test and multiple regression. Results: Although the prevalence of UI among the women was as high as 70.5%, the perception rate of UI was as low as 10.8%.Single voided volume of women without or with UI was 223 mL or 198 mL (p<.001), respectively; PVRV, 25.8 mL or 23.6 mL (p=.055); daytime frequency, 5.89 or 6.96 (p<.001); nocturia, 0.99 or 1.23 (p=.040). Age (${\beta}$=0.19, p=.001), single voided volume (${\beta}$=-0.16, p=.006), and nocturia (${\beta}$=0.12, p=.034) were associated with UI. Conclusion: The prevalence of UI was found to be 70.5% among the participants. The assessment of single urinary volume and nocturia through a bladder diary lends support to identifying UI for women over 40 years.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.39 no.4
• /
• pp.117-124
• /
• 2016

Stress is resistance to stimuli to destroy a balance of mind and body in order to maintain an original steady state : A type of response and avoidance. Mild stress, which happens in tension, has a positive effect to improve concentration, but most of stress is likely to be a main factor to damage health. This is because it causes physical ailments and psychological diseases (e.g., depression, anger, frustration, loneliness, and anxiety). The purpose of this study is to analyze the difference between two groups, daytime and night university students, on ego-state, stressors, and stress coping types to improve their academic achievement by reducing their stress. There were 266 university students, who participated in a survey from November 30, 2015 until September 30, 2016. The study employed three measuring instruments : Ego-gram, stressor scale, and stress coping type scale. All the collected data were analyzed through regression analysis and t-test. The results of the regression analysis showed no significant differences in ego-state, stressors, and stress coping types between two groups. However, the results of t-test showed significant difference between the two groups : In terms of ego-state, a CP (Critical Parent) average of the night university students was significantly higher than the daytime university students'. Also, there is a significant difference in employment, future issues, and economic issues : the daytime university students considered employment and future issues more serious, while the night university students had more mental burdens of economic issues. When it comes to coping stress types, there was no significant difference between the two groups.

• Korean Journal of Remote Sensing
• /
• v.27 no.6
• /
• pp.653-662
• /
• 2011

Land surface temperature (LST) is a one of the key variables of land surface which can be estimated from geostationary meteorological satellite. In this study, we have developed the three sets of LST retrieval algorithm from MTSAT-2 data through the radiative transfer simulations under various atmospheric profiles (TIGR data), satellite zenith angle, spectral emissivity, and surface lapse rate conditions using MODTRAN 4. The three LST algorithms are daytime, nighttime and total LST algorithms. The weighting method based on the solar zenith angle is developed for the consistent retrieval of LST at the early morning and evening time. The spectral emissivity of two thermal infrared channels is estimated by using vegetation coverage method with land cover map and 15-day normalized vegetation index data. In general, the three LST algorithms well estimated the LST without regard to the satellite zenith angle, water vapour amount, and surface lapse rate. However, the daytime LST algorithm shows a large bias especially for the warm LST (> 300 K) at day time conditions. The night LST algorithm shows a relatively large error for the LST (260 ~ 280K) at the night time conditions. The sensitivity analysis showed that the performance of weighting method is clearly improved regardless of the impacting conditions although the improvements of the weighted LST compared to the total LST are quite different according to the atmospheric and surface lapse rate conditions. The validation results of daytime (nighttime) LST with MODIS LST showed that the correlation coefficients, bias and RMSE are about 0.62~0.93 (0.44~0.83), -1.47~1.53 (-1.80~0.17), and 2.25~4.77 (2.15~4.27), respectively. However, the performance of daytime/nighttime LST algorithms is slightly degraded compared to that of the total LST algorithm.

• Korea Journal of Hospital Management
• /
• v.18 no.2
• /
• pp.15-32
• /
• 2013

Few public health researchers have paid research attention to the location of medical institutions in Korea. Previous studies were published in geography journals, and relied on limited data in terms of geographic regions and the type of medical institutions. This study utilized nationwide data covering 8 types of medical institutions. We obtained data from Health Insurance Review and Assessment Service and National Population and Housing Census. The correlation coefficients of resident, daytime, university-graduate population, and the population of different age groups (fewer than 15, 15~64, 65 or more) were compared to understand their relative association with the location of medical institutions. Medical clinic, dental clinic, oriental medical clinic, and pharmacy, all of which are almost completely operated by private sector, showed strong positive correlation with population. Hospital-level medical institutions, which are operated by both public and private sector, had moderate positive correlation. Daytime population and university-graduate population, rather than resident population, were more correlated with the location of medical clinics. The correlation coefficients of the population of 15~64 age group and the location of medical institutions were greater than that of other age groups. The results showed that daytime and university-graduate population are more important than resident population to explain the location of medicalrelated facilities. The results also suggests that the population of age groups (especially, 15~64) might be one of important influence factors in the location of medical institutions.

• Journal of Korean society of Dental Hygiene
• /
• v.15 no.4
• /
• pp.661-669
• /
• 2015

Objectives: The purpose of the study is to investigate of visiting time and major cause of disease by operating time changes of a university dental emergency room. Methods: This study was a retrospect study carried out by reviewing 9,172 records visiting the university emergency room from January 1997 to December 2009. Data were analyzed by frequency test, chi-square test, and logistic regression using SAS version 9.3. Results: Twenty four hours emergency room had 19 percent more patients than those in daytime emergency room. Daytime emergency room had more male patients during spring(26.6%) and winter(20.2%) than female patients(p<0.05). Female patients exceeded male patients during summer(24.4%) and autumn(36.2%)(p<0.05). Twenty-four hours emergency room had the maximal patients in autumn and the minimal patients in winter(p<0.05). The most common injury in the daytime was tooth fracture from 0 to 19 years old(p<0.05). Tooth fracture, jaw fracture, and soft tissue injury were the most common injury in dental emergency room and majority of the patients were the male(p<0.05). Conclusions: Twenty-four hours dental emergency room had a variety of causes of dental emergency thant that in the daytime. Twenty four hours dental emergency room must be prepared for the dental emergency patients at any time provided with personnel and facilities.