• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.26 no.4
• /
• pp.356-368
• /
• 2021

To understand the temporal variation of phytoplankton communities in a coastal area, the biomass and diversity were weekly investigated in the inner bay of Yeong-do, Busan. In the study area, chlorophyll a concentration ranged from 0.43~7.58 mg m^-3 during the study, indicating the study area was in mesotrophic or eutrophic status. The fractions of chlorophyll a occupied by large phytoplankton (> 3 ㎛ diameter) exhibited an average of 80% of total chlorophyll a in this study. Among the large phytoplankton, while Bacillariophyta was the most dominant in spring and summer, Cryptophyceae prevailed in the fall and winter. On the contrary, in the picophytoplankton community less than 3 ㎛ in diameter, Mamiellophyceae was the most dominant in most seasons, Cryptophyceae was relatively high with an average of 17.7 ± 17.6% throughout the year, but seasonal variations were large. Dinophyceae rarely occupied a higher fraction up to 60.4% of the picophytoplankton community. By weekly monitoring at a coastal station for 13 months, it is suggested that phytoplankton communities in coastal waters could be changed on a short time scale. If data are steadily accumulated at the time-series monitoring site for a long time, these will provide important data for understanding the long-term dynamics of phytoplankton as well as the impact of climate and environmental changes.

• Korean Journal of Poultry Science
• /
• v.49 no.2
• /
• pp.115-124
• /
• 2022

The objective of this study was to investigate the effects of dietary coenzyme Q10 (CoQ10) sources on the antioxidant defense system in the blood and liver of laying hens. Thirty-six 40-wk old Lohmann Brown hens were randomly assigned to three groups based on body weight, with four cages with three layers each. Laying hens were divided into one of the following groups: control (CON), powdered CoQ10 (PCoQ, 100 mg/kg diet), and emulsified CoQ10 (ECoQ, 100 mg/kg diet). All hens were fed a control diet or a control diet supplemented with powdered or emulsified CoQ10 ad libitum for five weeks. There were no differences in body weight, weight gain, and organ weights among the treatment groups, including the liver and spleen. The blood total antioxidant power (TAP) in the ECoQ group increased (P<0.05) by approximately 2-fold compared to that in the CON group. However, there was no significant difference in blood TAP levels between the PCoQ and ECoQ groups, although a decreasing trend (P<0.13) was observed for levels of TAP in the ECoQ group. The mRNA expression and specific activities of superoxide dismutase, glutathione peroxidase, and catalase in the liver were not affected by dietary CoQ10 or type of CoQ10. However, hepatic lipid peroxidation in the ECoQ group was lower (P<0.05) than in the CON group. In conclusion, emulsified CoQ10 increased blood TAP and decreased hepatic lipid peroxidation without affecting antioxidant enzymes, suggesting that emulsified CoQ10 might be more applicable as an active antioxidant supplement than powdered type in laying hens.

• Korean Journal of Remote Sensing
• /
• v.38 no.6_1
• /
• pp.1181-1189
• /
• 2022

Clouds are composed of tiny water droplets, ice crystals, or mixtures suspended in the atmosphere and cover about two-thirds of the Earth's surface. Cloud detection in satellite images is a very difficult task to separate clouds and non-cloud areas because of similar reflectance characteristics to some other ground objects or the ground surface. In contrast to thick clouds, which have distinct characteristics, thin transparent clouds have weak contrast between clouds and background in satellite images and appear mixed with the ground surface. In order to overcome the limitations of transparent clouds in cloud detection, this study conducted cloud detection focusing on transparent clouds using machine learning techniques (Random Forest [RF], Convolutional Neural Networks [CNN]). As reference data, Cloud Mask and Cirrus Mask were used in MOD35 data provided by MOderate Resolution Imaging Spectroradiometer (MODIS), and the pixel ratio of training data was configured to be about 1:1:1 for clouds, transparent clouds, and clear sky for model training considering transparent cloud pixels. As a result of the qualitative comparison of the study, bothRF and CNN successfully detected various types of clouds, including transparent clouds, and in the case of RF+CNN, which mixed the results of the RF model and the CNN model, the cloud detection was well performed, and was confirmed that the limitations of the model were improved. As a quantitative result of the study, the overall accuracy (OA) value of RF was 92%, CNN showed 94.11%, and RF+CNN showed 94.29% accuracy.

• Korean Journal of Poultry Science
• /
• v.48 no.4
• /
• pp.207-216
• /
• 2021

This study was conducted to determine the nutritional quality of two newly-developed native chicken strains, compared to the commercial Korean native chicken. A total of 600 chickens (CON: Hanhyup No. 3, CL1: candidate line C, CL2: candidate line D) raised under the same conditions were slaughtered at either 5 or 12 weeks. Leg meat was then obtained and analyzed for its physicochemical properties. The results showed that regardless of the growing period, there was no variation in proximate composition (P>0.05), except for crude protein, between strains. Water holding capacity did not differ between strains at either slaughter age; however, it was significantly lower in the 12-week group than in the 5-week group (P≤0.05). For both skin and muscle color, a^* and b^* values were lower at 12 weeks than at 5 weeks (P≤0.05). DPPH radical-scavenging activity tended to be lower at 12 weeks than at 5 weeks (P≤0.05). Furthermore, all chickens slaughtered at 5 weeks were found to have greater contents of linoleic acid (18:2) and polyunsaturated fatty acids (PUFA) and lower atherogenicity and thrombogenicity indices than those slaughtered at 12 weeks (P≤0.05). However, anserine, betaine, and glucose were more concentrated among the lines at 12 weeks than at 5 weeks (P≤0.05). In conclusion, the quality traits of native chickens were distinct by different production stages rather than chicken lines.

• Korean Journal of Psychosomatic Medicine
• /
• v.29 no.2
• /
• pp.111-120
• /
• 2021

Objectives : Shift work has been known to cause various health problems by making it difficult for humans to adapt to their natural circadian rhythms. In particular, shift workers tend to complain of sleep difficulties associated with work schedules, and sometimes use alcohol as a self-medication to induce sleep. To date, no clear mechanism has been identified regarding the link between shift work and sleep, between shift work and drinking. This study aims to confirm the relationship between shift work and sleep, and to analyze whether the change in sleep caused by shift work causes drinking. Methods : This study included 11360 people (5704 men and 5656 women) among the Korean National Health and Nutrition Survey data in 2014, 2016 and 2018. The work type between 6am-6pm was defined as day work, and other work types were defined as shift work. Using logistic regression analysis, the relationship between shift work and sleep quality, shift work and high risk drinking, drinking amount at 1 time, drinking frequency were analyzed. In addition, we analyzed whether sleep mediates the relationship between shift work and drinking using mediated analysis. Results : Shift work showed a significant negative relationship with sleep quality in men and women (male OR=1.37, 95% CI 1.11-1.70, female OR=1.26, 95% CI=1.05-1.50). There was no significant relationship between shift work and alcohol in the case of men, but in the case of women, there was a significant positive relationship between shift work and the number of alcohol consumption (OR=1.34, 95% CI=1.04-1.72). When mediation analysis was conducted, it was found that women's sleep quality partially mediated the relationship between shift work and the frequency of drinking. Conclusions : The results of this study suggest that shift work causes sleep difficulties, and in the case of women, drinking can be induced through the partial mediating effect of sleep. Considering that women are more likely to choose drinking as a coping method for sleep problems, more active interventions for female shift workers are needed.

• Korean Journal of Poultry Science
• /
• v.49 no.4
• /
• pp.255-264
• /
• 2022

This study was performed to investigate the effects of dietary supplementation with ginseng by-products on growth, organ development, blood biochemical profiles, immune response, and stress parameter of broilers reared in high ambient temperatures. One hundred one-day-old male chicks (Ross 308) were used. At week two, the birds were randomly allocated into five dietary groups; control (CON), 0.5% ginseng berry (GB1), 1.0% ginseng berry (GB2), 0.5% ginseng leaves and stems (GLS1), and 1.0% ginseng leaves and stems (GLS2). The temperature was maintained at 32±1℃from 9 AM to 5 PM. Growth, serum immunoglobulins and corticosterone levels were monitored and analyzed. No significant differences among groups were observed in growth. However, during the finisher period (21~35d) and overall period (7~35 d), body weight gain in all supplemented groups tended higher than CON group. Blood biochemical profiles did not significantly differ among treatment groups except in bilirubin level. Serum immunoglobulins and corticosterone level showed no significant differences among groups. IgM and IgG levels were numerically higher in GLS1 than in other groups, but the difference was not significant. Corticosterone level also tended lower in all supplemented groups than in CON group, and larger decreases were observed in groups with higher ginseng by-product concentration. In conclusion, dietary supplementation of ginseng by-products shows potential to reduce heat stress in growing broilers with no negative effect on productivity.

• Korean Journal of Poultry Science
• /
• v.49 no.4
• /
• pp.189-197
• /
• 2022

This study was conducted to compare the egg productivity, egg quality, and blood characteristics of laying hens with different laying rates, and the frequency and cumulative duration of the sitting behavior observed before laying was investigated. Twelve 45-week-old Hy-Line Brown laying hens were randomly assigned to two treatment groups with three replicates. Treatment groups were classified as layers laying over 80%(high egg performance layers; HEP) and layers laying below 50%(poor egg performance layers; PEP). The experiment lasted 4 weeks. HEP showed higher hen-house egg production ratio and egg mass and lower feed conversion ratio(FCR) (P<0.05) compared with PEP, although egg weight was higher in PEP (P<0.05). In terms of egg quality, PEP showed differences in eggshell quality (eggshell color, eggshell thickness, and eggshell weight) (P<0.05). Additionally, HEP showed high triglycerides(TG), and PEP showed high alanine transaminase(ALT) level (P<0.05) in serum collected in the morning. In the afternoon, the HEP showed higher lactate dehydrogenase(LDH) levels (P<0.05). No differences in the Ca: P ratio were observed between layers with different laying rates. One hour before egg laying, HEP exhibited sitting behavior 4 times on average, each lasting 25 minutes. In conclusion, egg production and quality differ between HEP and PEP, and HEP showed frequent sitting behavior before egg laying. However, additional research is necessary to explore approaches other than specific behavioral observation to distinguish poor layers in the flock for application in farms.

• Journal of Korea Entertainment Industry Association
• /
• v.15 no.7
• /
• pp.225-233
• /
• 2021

This study quantitatively compares and analyzes lower extremity muscle activity and motor neurons by performing blood flow-restricting aerobic training in the lower extremities, which is closely related to aerobic capacity for health, in normal people, and provides basic data to suggest the effectiveness of an effective blood-restricting exercise program. would like to provide A group of 10 people who applied aerobic exercise on a treadmill by restricting blood flow to 140 mmHg of pressure was set as Experimental Group I. And 11 people who applied only aerobic exercise on a treadmill were randomly assigned as a control group. The intervention program was implemented on a treadmill for 4 weeks, 3 times a week, once a day, for 30 minutes once. In addition, muscle activity and motor neurons were measured and analyzed using surface electromyography before intervention. As a result of the study, the muscle activity of the rectus femoris, biceps femoris, tibialis anterior and gastrocnemius was significantly increased (p<.001) in the pre-and-poster comparison within the group of experimental group I (p<.001). In the pre-and-poster comparison of the control group, the muscle activity of the rectus femoris, biceps femoris, tibialis anterior and gastrocnemius was significantly increased (p<.001). In comparison of changes between groups, there was a significant difference in the activity of the rectus femoris muscle (p<.05). Combining aerobic exercise in parallel with lower extremity blood flow restriction can be developed into an injury prevention exercise program that can restore functional activity in rehabilitation training for elite athletes and elderly people with weak joints. In addition, based on these results in future research, it is considered that it is necessary to expand the scope of non-normal subjects and conduct various studies according to the pressure intensity.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.40 no.5
• /
• pp.662-669
• /
• 1995

To clarify the effect of temperature during ripening on grain quality, rice plant which was grown under normal natural conditions untill heading stage was subjected various temperature regimes during grain filling stage. Three varieties, Odaebyeo, Hwaseongbyeo and Dongjinbyeo were used. Grains on primary and secondary-rachis branches were harvested seperately and measured specific gravity, grain size and weight. The optimum daily temperature for grain filling of rice during ripening period was about 22$^{\circ}C$ and grain filling under alternating temperature(26/18$^{\circ}C$, day /night) was better than constant temperature (22 /22$^{\circ}C$) based on 1, 000-grain weight and yield. Grain size based on volume per grain was smallest under the constant temperature of 22 /22$^{\circ}C$. The size of secondary-rachis branches was smaller than primary-rachis branch. The difference in size between primary and secondary-rachis branches was biggest in Hwaseongbyeo, followed by Odaebyeo and Dongjinbyeo. The temperature regimes treated did not influence the grain size difference between branches so much. The 1000-grain weight was lighter under high temperature than low temperature in Odaebyeo, but reversed tendency was observed in Dongjinbyeo of secondary rachis-branches.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.41 no.5
• /
• pp.514-520
• /
• 1996

To clarify the proper nitrogen application level for rasing rice infant seedling under different nursery soil, Dongjinbyeo was raised at seedling box with different basal nitrogen level. The results are as follows. The higher the nitrogen level was, the lower emergence rate and the lower establishment rate. The establishment rate was less than 90%, when the nitrogen was more than 2g/box in hill soil and more than 1g/box in paddy soil. The more the nitrogen level was, the higher the seedling height in hill soil, but was higher in the order of N-2, 3, 1 and 0g /box. Leaf number wasn't significantly different between nusery soils and among nitrogen levels when seedling was raised more than 6 days. The endosperm survival rate was decreased as the increased nitrogen level, but wasn't different between the nursery soils. Amount of root was decreased as the increased nitrogen level in paddy soil, but was heavier in the order of N-1, 0, 2 and 3g /box in hill soil. Mat formation was better as the nitrogen level was decreased in all nursery soils. Considering the emergence rate, seedling charactors and mat formation, the proper nitrogen levels seemed to be 2g /box for hill soil and 1g /box for paddy soil.