• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.3
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• pp.208-212
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• 2003

Extended light illumination by street lamp and automobile light has provoked problem in farmland. Night break was imposed by incandescent lamp (50∼60 lux) for 10 minutes every three hours during 12 hours dark period increased culm length compared to continuous dark of 12 hours, and decreased the number of grains per spike in rice. However, these characters were increased by 12 hours dark period with and without night break as compared to 9 hours continuous dark condition. Compared to 12 hours continuous dark condition, night break delayed heading by 9 and 26 days and 9 hours continuous dark condition delayed it by 47 and 41 days in Ilpumbyeo and Hwaseongbyeo, respectively. Night break increased stem length and node number, while decreased pods of soybean cultivar Hwanggeumkong. The stem length and node number were increased by 9 hours continuous dark condition compared to 12 hours dark condition with and without night break. Compared to 12 hours continuous dark rendition, night break delayed flowering by 4 days and to 9 hours continuous dark condition by 19 days.

• Korean Journal of Medicinal Crop Science
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• v.14 no.5
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• pp.311-316
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• 2006

The content of four phonolic acids 1-4, and two flavonol aglycones 14 and 15 from Orostachysjaponicus A. Berger grown under night-break and day-length controlled experiments was estimated and compared with those in wild plants. The amount of the phenolic acids 1-4 and the flavonol aglycones 14 and 15 increased with increasing light irradiation under both the night-break and day-length control conditions. It was disclosed that the cultivation conditions such as the night-break and the day-length control were not adversely affect the production of phenolic acids and flavonols in Orostachys japonicus A. Berger extracts.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.2
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• pp.236-242
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• 1996

Orostachys japonjcus, called Wasong in herb medicine, has been artificially cultivated as an anti-tumor medicinal. The experiment was done to examine the effect of night-break periods imposed immediately before its bolting time on its morphological, flowering-related characters and fraction dry weights. After a plant was grown in a 15cm plastic pot containing a 2:1 soil:Peat moss mixture for about 3 months, three different night-break periods (0.5, 1 and 2 hours) around midnight were treated from Aug. 24. to compare with the natural daylength. The plants were sampled 6 times by 2-week interval after the treatments. Plant height and inflorescence length of all the treatments inclined with time lapse after the treatment and were shorter in 2 hour night-break due to slow increment than in the other treatments, while stem diameter showed reverse result. All the treatments except 2 hour night -break were nearly same in fraction, shoot and total dry weights per plant; two hour night-break treatment had greater leaf and bract weight from 6 weeks, greater stem, shoot and total weights from 2 weeks and greater root weight from 4 weeks but did less floret weight after the treatment. Although florets on the inflorescence were formed in 2 hour night-break treatment, flowering florets and flowering plants never occurred. In the other treatments showed the similar response, however, more florets appeared from 2 weeks, flowering florets was sharply increased from 6 weeks and flowering plants were reached up to 100% from 6 to 8 weeks after the treatment. Inflorescence length or number of total florets per plant in 2 hour night-break was positive-correlated to all the fraction dry weights except that those of natural daylength was not done, meaning that its artificial cultivation should permit bolting to secure more shoot dry matter.

• Journal of Korean Clinical Nursing Research
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• v.27 no.2
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• pp.165-178
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• 2021

Purpose: To analyze nurses' shift work according to the government guidelines for night work and their perceptions of their work schedules. Methods: The study sample included 487 nurses who provided information on their schedules, including the normal working hours of each shift, and overtime per shift during September 2020. Nurses' perceptions were measured in terms of satisfaction, appropriateness for work-life balance, and fairness to their work schedule. Results: One-third of the respondents worked more than 40 hours per week. The average overtime hour was 1.14 hours per shift. Unsocial hours (8 pm to 6 am on weekdays, midnight to midnight on weekends and public holidays) accounted for 56.4% of all working hours. During their last night shift, on average, nurses worked 9.62 hours and had a break of 39 minutes, although 20.5% reported no break. Sixty-eight percent of nurses had at least one between-shift break shorter than 48 hours after a consecutive night shifts. Fifty-seven percent were satisfied with their schedule. One-third perceived their schedule as appropriate for work-life balance, and two-thirds perceived that days off on weekends and nights were fairly distributed within the unit. Working and overtime hours had an inverse relationship with all three aspects of nurses' perceptions. A higher proportion of unsocial hours and having no breaks during the night shift were associated with lower perceptions of fairness. Conclusion: Reducing working hours, ensuring breaks during night shifts, and increasing rewards for unsocial hours are required to improve nurses' perceptions and reduce turnover due to shift work.

• Korean Journal of Medicinal Crop Science
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• v.15 no.4
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• pp.256-260
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• 2007

Year-round cultivation of a monocarpic plant Orostachys japonicus should be possible in case to controlling floret flowering. To give some information on its year-round cultivation, this study was carried out to examine the effect of night-break treatment time (June 10, Aug. 25) on its growth, morphological characters, and flowering. Night-break treatment of 2 hours at midnight were done since Aug. 25 and heating were made under $20^{\circ}C$ Samples were taken every 4 weeks from Aug. 25. Growth, morphological and flowering related characters were measured from each sample until March 9. Plant height, inflorescence length, number of leaves including bracts and stem diameter were greater in the earlier treatment than in the later one. Leaves and bracts, floret, stem, root, shoot and total dry weights showed the same response as plant height did to the night-break treatment time. Florets were more formed in the earlier treatment than in the later treatment in which they were flowered only on March 9, meaning that its year-round cultivation should be possible under night-break treatment before bolting and heating during winter season.

• Journal of Bio-Environment Control
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• v.22 no.1
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• pp.43-47
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• 2013

This study was conducted to develop the most effective method in promoting onion set in cultivars 'Josaengsseondebol' and 'Daeji' for all year-round production. This was done by extending the day length for 41 days. For both cultivars, the period to reach the maximum number of leaves developed was shortened as the exposure to day length increased. Between the two cultivars, 'Josaengsseondebol' reaches its maximum leaf formation for a shorter duration compared with 'Daeji'. In effect to bulb size, cultivar 'Josaengsseondebol' having a night break of 1, 2, and 16 hours light condition had better bulb enlargement compared with the non-treated bulbs. In the case of cultivar 'Daeji', only bulbs exposed to a night break of 2 and 16 hours light condition had better bulb enlargement. The percentage of marketable set yield in cultivar 'Josaengsseondebol' having a night break of 1 hr, 2 hrs, 16 hrs light condition, and control or untreated bulbs were 84%, 92%, 90%, and 6% respectively. In the case of cultivar 'Daeji', treated with a night break of 1 hr, 2 hrs, 16 hrs light condition, and untreated bulbs had a percentage marketable set yield of 7%, 55%, 64%, and 0% respectively. Based on these results, it is therefore concluded that night break treatment is considered to be effective method in promoting off-season onion set cultivation in cultivar 'Josaengsseondebol'.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.600-607
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• 1995

Orostachys japonicus, called Wasong and used as anti-tumor medicinal plant, was cultivated in plastic house. The experiment was done to clarify the effect of long-day and night-break treatment at the timing of bolting on its morphological characters, organ dry weight and flowering of florets. After grown in 15cm plastic boxes containing 2:1 soil:peat moss mixture for about 4 months, long-day of 16 hours and night-break of 2 hours around midnight were treated from Sept. 9. The plants were sampled 5 times at 2-week interval after the treatments. Long-day and night-break treatment delayed the growth of inflorescence and showed greater stem diameter on the last sampling and no. of leaves and bracts than the natural daylength. The treatments also had greater leaf and bract dry weight since 2 weeks, and the other fraction and total dry weights since 4 weeks but less floret dry weight from 4 to 6 weeks after the treatments than the natural daylength. The treatments, however, decreased no. of flowered florets and ratio of flowering plants although all the treatments showed nearly the same no. of total florets per plant until 6 weeks after the treatments, late October, which resulted in the modification of source to sink or vice versa. In the natural daylength, the florets were functioned as sink, while root, leaf and bract as source, but in the long-day and night-break treatments stem and florets were done as sink.

• Journal of Bio-Environment Control
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• v.17 no.2
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• pp.150-156
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• 2008

The influences of night break by costly artificial light sources were investigated on the photo-morphogenesis and growth of leafy perilla (Perilla ocymoides L.). The irradiation of red, blue, and three-colored light for night break significantly increased the stem length and stem diameter compared to dark. Three-colored light gave the highest fresh and dry weight of stem, followed by red and blue light. Floral induction was suppressed up to 100 days after the night break, by red and three-colored light, but the plants grown under the dark or treated with blue light showed 85% and 31% flowering rate, respectively. The time needed for floral induction after night break was 60 days in dark and 80 days in blue light. The number of leaf, leaf area, and fresh weight per plant were the highest in red and three-colored light night break, followed by blue light and dark. The photosynthetic rate observed 80 days after night break was the highest in red light, followed by blue and three-colored light. A low light compensation point of $20\;{\mu}mol\;m^{-2}{\cdot}s^{-1}$ was observed in three-colored light, while red and blue light tended to show higher measurements.

• Korean Journal of Medicinal Crop Science
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• v.13 no.6
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• pp.250-254
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• 2005

The contents of flavonol glycosides, $kaempferol-3-O-{\beta}-D-glucoside$(1), $kaempferol-3-O-{\beta}-D-glactoside$ (2), $kaempferol-3-O-{\beta}-D-rhamnoside$ (3), $quercetin-3-O-{\beta}-D-glucoside$ (4) and $quercetin-3-O-{\alpha}-D-rhamnoside$ (5) in the houseleeks controlled by night-break, day-length control, and temperature during overwintering were determined to be compared with those in wild one. The contents of the flavonol glycosides 1-5 in the houseleeks were decreased roughly with warming during overwintering, and increased with longer light duration under the day-length control experiments. While warming functioned negatively on the production of the flavonol glycosides in the houseleek, longer light irradiation did positively during overwintering.

• Korean Journal of Agricultural Science
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• v.40 no.4
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• pp.297-303
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• 2013

This study was carried out to examine the effect of Red LED (660 nm) and fluorescent lamp for night break (NB) treatments of each 3 hours (22:30-01:30), 4 hours (22:00-02:00) and 5 hours (21:30-:02:30) per day for 53 days on flower bud initiation and growth in Chrysanthemum cv. 'Baekma' and cv. 'Jinba'. The days to flower budding after short-day treatment in 'Baekma' was longer at fluorescent lamp 4 hr (21.0 days) and 5 hr (20.5 days) NB, and it was shorter at Red LED 3 hr (14.2 days). The days to flowering after short-day treatment in 'Baekma' was longer at fluorescent lamp 4 hr (54.0 days), 5 hr (53.5 days) NB, and Red LED 5 hr (53.3 days), and it was shortest at Red LED 3 hr (50.2 days) NB treatment among all treatments. The days to flower budding after short-day treatment of 'Jinba' was longer at fluorescent lamp 4 hr (20.6 days) and was shorter at Red LED 3 hr (14.1 days) among all treatments. Similarly, the days to flowering after short-day treatment of 'Jinba' was longer at fluorescent lamp 4 hr (55.3 days) and was shortest at Red LED 3 hr (50.2 days) among all treatments. Therefore, inhibition of flower bud initiation was the most effective under fluorescent lamp 4 hr treatment. The length of cut flower of 'Baekma' was increased by fluorescent lamp 4 hr, 5 hr, and Red LED 5 hr, but of 'Jinba' was longer at LED 4 hr and 5 hr treatment. The weight of cut flower of 'Baekma' was heaviest at fluorescent lamp 5 hr treatment and was at Red LED 5hr treatment for 'Jinba' even though there was not statistically significant difference between 'Baekma' and 'Jinba'. Consequently, under fluorescent lamp 4 hr for night break was the most effective on flower bud initiation, flowering inhibition and cut-flower characteristics in 'Baekma' and 'Jinba'.