• 한국해양학회지
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• v.7 no.2
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• pp.86-97
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• 1972

The tides, tidal currents and tidal prisms at Inchon Harbor are studied with recent data. The tides at Inchon Harbor is of semi-diurnal type having a spring range of 798cm and a phase age of 2 days. The monthly mean sea level at Inchon has a maximum at August and a minimum at January with a annual range of about 40cm. the tidal currents at Inchon Outer Harbor are of semi-diurnal type same as tides and nearly reversing type. The flood and ebb currents set north and south with a velocity of about 90-175 cm/sec and 120-225 cm/sec at spring tide and begin 0.2 hours after L.W. and 0.7 hours after H. W., respectively. Non-tidal currents flow southward with 10-20 cm/sec at west side of the stream and northward with 15-20 cm/sec at east side of the stream at Inchon Outer Harbor. The flood volume through the Inchon Outer Harbor fluctuates fortnightly from 590 10$\^$6/㎥ spring tide to 260 $10^6/m^3$ at neap tide and ebb volume changes from 470 $10^6/m^3$ at spring tide to 200 $10^6/m^3$ at neap tide, respectively. The flow area along the channel to the Estuary of Yeomha is controlled by the tidal prism as expressed by $A=1.14{\times}10^{-4}P^{0.966}$

• ALGAE
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• v.22 no.2
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• pp.95-106
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• 2007

Blooms of Chattonella species are normally during summer in inland seas with high nutrients from the land and inflowing water. These blooms cause mass fish kills worldwide. We isolated a Chattonella strain from the south coast of Korea and identified it as C. antiqua. It is known that the morphological changes of phytoplankton correspond to the diurnal vertical migrations that follow an intrinsic biological clock and a nutrient acquisition mechanism during the day and night. In electron micrographs, C. antiqua clearly showed a radial distribution of lipid bodies in subcellular regions and plastids composed in which thylakoid layers were perpendicular to the surface. A single pyrenoid was present in each plastid and it was found at the end of the plastid towards the center of the cell. Throughout the day, plastids of C. antiqua cells appeared as an expanded net-like recticulum. During the night, however, the plastids changed their shape and contracted toward the cell periphery. The electron density of pyrenoids was increased in cells harvested during the night.

• Korean Journal of Occupational Health Nursing
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• v.18 no.1
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• pp.14-21
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• 2009

Purpose: This study was performed to investigate the effect of shift work on diurnal blood pressure (BP) pattern in nurses. Method: We studied 20 healthy nurses engaged in 3 shift work. 24-hour ambulatory BP monitoring was performed to each nurse two times during the day and night shift. Five nurses were excluded because of inadequate BP measurement. Results: All subjects were female. The mean age was 27.4 years (range: 23-33 years) and mean body mass index was 19.7 Kg/$m^2$ (range: 18.0-21.2 Kg/$m^2$). The changes of systolic BP ($17.8{\pm}9.1$ vs. $13.2{\pm}4.7%$, p=0.031), diastolic BP ($22.3{\pm}8.7$ vs. $17.3{\pm}9.0%$, p=0.061), and heart rate ($25.2{\pm}5.2$ vs. $12.5{\pm}8.7%$, p=0.001) during the sleeping period were decreased after a night shift compared with day shift. The non-dipper group significantly increased from 20% to 40% after a night shift (p=0.018). Conclusion: Working night shift is significantly associated with non-dipper status in nurses.

• ALGAE
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• v.21 no.2
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• pp.245-251
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• 2006

Diurnal and age-related changes in air pressure were measured in air bladders of Ascophyllum nodosum from the Atlantic coast of Nova Scotia. Exterior and interior bladder volumes vary significantly with 4 and 6 y bladders being about 40% larger than 2 y bladders (p < 0.01). Freshly collected bladders yielded a mean pressure of 40.8 ± 6.5 cm H2O. Overnight (20 h) dark treatment at 15°C generated pressure reductions by 80% in 2 y bladders but only by about 30% in 4 and 6 y bladders. Furthermore, in 2 y bladders 8 out of 11 bladders were reduced to atmospheric pressure. Pressure losses were inversely related to pressure recovery after 2.5 h in natural daylight, but after 5 h in daylight there was no significant difference in pressure within the age groups. Even under 25% of full illumination, bladders inflated to full pressure after 5 h. The results show that differences in bladder age and bladder wall thickness have roles in diurnal patterns of bladder inflation and deflation. These results confirm that bladder inflation is based on photosynthetic O2 production and not on partial pressures of O2 in the surrounding medium as was suggested for Sargassum. Chemical analyses of fluid recovered after the interior of bladders were washed with saline showed no evidence for the occurrence of surfactant that might be responsible for maintaining the air-liquid interface.

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.1
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• pp.60-64
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• 1986

To determine the effects of soil moisture on diurnal changes of photosynthesis, transpiration and stomatal resistance, sorghum and soghum-sudangrass hybrid were grown at large concrete pots maintained at 100, 80, 60 and 40% of field moisture capacity. Photosynthesis were measured from a.m. 6 to p.m. 6 on a fine day. 1. Photosynthesis and transpiration reacted similarly to water stress and environmental factors, and they reached at their maximum points from noon to 2 p.m. and decreased sharply after 4 p.m. 2. Photosynthesis and transpiration of sorghum were higher at 60% field moisture capacity than those of the other field moisture capacities. In sorghum-sudangrass hybrid, photosynthesis was in the order of 60>80>40>100% and transpiration was in the order of 60>80>100>40%. 3. Stomatal resistance did not show clear diurnal change and was the lowest at 60% among four field moisture capacities.

• Sleep Medicine and Psychophysiology
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• v.2 no.1
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• pp.55-64
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• 1995

During sleep, relatively major respiratory physiological changes occur in healthy subjects. The contributions and interactions of voluntary and metabolic breathing control systems during waking and sleep are quite different Alterations of ventilatory control occur in chemosensitivity, response to mechanical loads, and stability of ventilation. The activities of intercostal muscles and muscles involved in regulating upper airway size are decreased during sleep. These respiratory physiological changes during sleep compromise the nocturnal ventilatory function, and sleep is an important physiological cause of the nocturnal alveolar hypoventilation. There are several causes of chronic alveolar hypoventilation including cardiopulmonary, neuromuscular diseases. Obstructive sleep apnea syndrome (OSAS) is an important cause of nocturnal hypoventilation and hypoxia. Coexistent cardiopulmonary or neuromuscular disease in patients with OSAS contributes to the development of diurnal alveolar hypoventilation, diurnal hypoxia and hypercapnia. The existing data indicates that nocturnal recurrent hypoxia and fragmentation of sleep in patients with OSAS contributes to the development of systemic hypertension and cardiac bradytachyarrhythmia, and diurnal pulmonary hypertension and cor pulmonale in patients with OSAS is usually present in patients with coexisting cardiac or pulmonary disease. Recent studies reported that untreated patients with OSAS had high long-term mortality rates, cardiovascular complications of OSAS had a major effect on mortality, and effective management of OSAS significantly decreased mortality.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.5
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• pp.478-483
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• 1997

Six adult female Murrah buffaloes of about 12 years were exposed to solar radiation during summer when minimum and maximum ambient temperatures were 27.1 and $44.1^{\circ}C$, respectively. The skin surface temperature at forehead, middle pinna, neck, rump, foreleg, hind legs were recorded using non-contact temperature measuring instrument and respiration rate and rectal temperature were measured throughout the 24 hours starting from 6:30 AM. The diurnal fluctuations and temperature gradients have been reported for buffaloes. During summer when ambient temperature and solar radiation was maximum, adult buffaloes were not able to maintain their thermal balance even after increasing the pulmonary frequency 5 - 6 times. The changes in skin temperature at various sites indicate that the temperature of skin surface not only varies in relation to exposure but also due to water diffusion and evaporation.

• BMB Reports
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• v.48 no.4
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• pp.209-216
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• 2015

Stress is now recognized as a universal premorbid factor associated with many risk factors of various chronic diseases. Acute stress may induce an individual's adaptive response to environmental demands. However, chronic, excessive stress causes cumulative negative impacts on health outcomes through "allostatic load". Thus, monitoring the quantified levels of long-term stress mediators would provide a timely opportunity for prevention or earlier intervention of stressrelated chronic illnesses. Although either acute or chronic stress could be quantified through measurement of changes in physiological parameters such as heart rate, blood pressure, and levels of various metabolic hormones, it is still elusive to interpret whether the changes in circulating levels of stress mediators such as cortisol can reflect the acute, chronic, or diurnal variations. Both serum and salivary cortisol levels reveal acute changes at a single point in time, but the overall long-term systemic cortisol exposure is difficult to evaluate due to circadian variations and its protein-binding capacity. Scalp hair has a fairy predictable growth rate of approximately 1 cm/month, and the most 1 cm segment approximates the last month's cortisol production as the mean value. The analysis of cortisol in hair is a highly promising technique for the retrospective assessment of chronic stress. [BMB Reports 2015; 48(4): 209-216]

• Journal of Environmental Health Sciences
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• v.34 no.1
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• pp.1-11
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• 2008

The purpose of this study was to investigate air quality in Chungju, Korea, using data obtained with a local air quality monitoring system. We have utilised cohort studies to investigate the relations between environmental pollution and the health of residents near large industrial complexes since 2004. This study analyzes the $O_3,\;NO_2,\;SO_2,\;CO\;and\;PM_{10}$ concentration in Chungju from 2002 to 2006. Air pollutants are closely related to the number of manufacturing facilities and cars, energy utilization and weather conditions. Generally, the diurnal concentration of air pollutants in Chungju reached the highest level in the morning (about$08:00{\sim}$) and early evening (about$19:00{\sim}$). On the other hand, the diurnal concentration of ozone as recorded gives the highest amount in late afternoon (about$16:00{\sim}$) and lowest in early morning (about$08:00{\sim}$). The concentration of air pollutants in Chungju was highest from winter to spring and lowest during the summer season. On the other hand, the monthly variation of ozone concentration was greatest in June and smallest in December. Also the, $PM_{10}$ concentration posted the highest record in April and the lowest during September. In general, this study analyzed air pollution changes in Chungju as well as in large scale industrial complex regions within Korea such as Ulsan, Pohang, Kwangyang, Sihwa Panwol and Gangneung in Korea. We compared the air quality of Chungju with those of these cites and found that air pollutants except for CO in Chungju was generally lower than large industrial complex regions.

• Journal of Ecology and Environment
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• v.44 no.2
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• pp.106-114
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• 2020

Background: Determining patterns of habitat use is key to understanding of animal ecology. Approximately 1% of bird species use brood parasitism for their breeding strategy, in which they exploit other species' (hosts) parental care by laying eggs in their nests. Brood parasitism may complicate the habitat requirement of brood parasites because they need habitats that support both their host and their own conditions for breeding. Brood parasitism, through changes in reproductive roles of sex or individual, may further diversify habitat use patterns among individuals. However, patterns of habitat use in avian brood parasites have rarely been characterized. In this study, we categorized the habitat preference of a population of brood parasitic lesser cuckoos (Cuculus poliocephalus) breeding on Jeju Island, Korea. By using compositional analyses together with radio-tracking and land cover data, we determined patterns of habitat use and their sexual and diurnal differences. Results: We found that the lesser cuckoo had a relatively large home range and its overall habitat composition (the second-order selection) was similar to those of the study area; open areas such as the field and grassland habitats accounted for 80% of the home range. Nonetheless, their habitat, comprised of 2.54 different habitats per hectare, could be characterized as a mosaic. We also found sexual differences in habitat composition and selection in the core-use area of home ranges (third-order selection). In particular, the forest habitat was preferentially utilized by females, while underutilized by males. However, there was no diurnal change in the pattern of habitat use. Both sexes preferred field habitats at the second-order selection. At the third-order selection, males preferred field habitats followed by grasslands and females preferred grasslands followed by forest habitats. Conclusions: We suggest that the field and grassland habitats represent the two most important areas for the lesser cuckoo on Jeju Island. Nevertheless, this study shows that habitat preference may differ between sexes, likely due to differences in sex roles, sex-based energy demands, and potential sexual conflict.