• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.439-446
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• 2009

Nitrogen balance in the regional scale which was calculated the difference between nitrogen input and output was estimated to assess the impact of rice cultivation on water environment. Nitrogen balances in Gyeonggi province, where nitrogen concentration in irrigation water was high and in Chungnam province, where nitrogen absorbtion by rice was high, were -5.4 and -8.3 kg $-8.3kg\;ha^{-1}\;yr^{-1}$, respectively. Nitrogen balances of paddy field in Gangwon province, where nitrogen output was small and irrigation water was clean, and in Gyeongnam province, where organic matter content of soil was high and rice yield was low, were 4.9 and $14.0kg\;ha^{-1}\;yr^{-1}$, respectively. Average nitrogen balance and total nitrogen absorption of paddy field in Korea were estimated to $-0.3kg\;ha^{-1}\;yr^{-1}$ and $-3,315Mg\;yr^{-1}$, respectively. When the nitrogen concentration in irrigation water was increased by $1mg \;L^{-1}$, nitrogen balance of rice paddy changed by $-2.91kg\;ha^{-1}\;yr^{-1}$. Also, when nitrogen fertilizer applied was decreased from 110 to $90kg\;ha^{-1}$ and the same harvest was maintained, the nitrogen absorption by rice paddy from irrigation water was estimated to increase by 10,600 Mg per year in Korea. However, in cases, the harvest was reduced to either 90% or 85%, nitrogen balances were changed from -11.7 to -2.3 and $2.4kg\;ha^{-1}$, respectively. These results suggest that the reduction of nitrogen fertilizer use may not always lead to a negative nitrogen balance and sustainable agriculture can achieve by not cutting down the use of fertilizer only but by reduction of fertilizer application concurrently by maintenance of harvest and by utilization of environmental characteristics such as nutrient contents in irrigation water and soils.

• Journal of Gifted/Talented Education
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• v.21 no.1
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• pp.57-81
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• 2011

The purpose of this study was to explore the quality of life of musically talented students as measured by their external experiences (e.g., activities, companions) and internal experiences (e.g., flow, emotion). The participants in this study were 33 musically talented students (10 males, 23 females) aged 13 to 19. Study data were collected for 7 consecutive days using the Experience Sampling Method (ESM), which employs a cellular-phone as a signaling device. The results were as follows: First, in response to the 1625 random signals, musically talented students reported that 40.9% of their time was spent on productive activities. An additional 33.4% of time was used for maintenance activities and the rest of their time was spent on leisure/social activities. Also, musically talented students reported that 48.5% of their time was spent alone. When they were alone, they spent a lot of time engaging in productive activities (44.3%). Second, in order to measure the flow of their life, two methods were used. One used a 4-channel flow model (i.e. apathy, boredom, flow, anxiety) and the other used 8 dimensions and conditions of the flow experience (i.e. concentration, self-consciousness disappears, action and awareness merge, distorted sense of time, freedom from worry about failure, clear goals, immediate feedback, balance between challenges and skills). According to the former, when engaged in music-related activities, musically talented students usually reported flow (54.0%), while they felt apathy (41.3%) for daily routines activities. According to the latter method, musically talented students experienced flow for most productive activities, while they experienced flow least for maintenance activities. Emotional variables of ESF are comprised of 10 semantic scales (i.e. happy-sad, strong-weak, active-passive, sociablelonely, proud-ashamed, involved-detached, excited-bored, clear-confused, relaxed-worried, cooperative-competitive). Musically talented students reported experiencing the most positive emotion for social activities and experiencing the most negative emotion for maintenance activities. Results of this study assert that musically talented students had to trade off immediate enjoyment for developing their special gifts. They could not afford as much time for socializing with friends, and they had to spend more time alone compared to their peers without such gifts. Consequently, they were found to deprive themselves of the spontaneous good times that teenagers usually thrive on. They were helped in this respect by their autotelic personality traits, especially their strong need for achievement and endurance. The downside, however, is that the moment-to-moment quality of their moods suffered. The argument concerning musically talented students applies for all adolescents. The choices that talented students must make between immediate gratification and long-term development, and between solitude and companionship, are the same choices every young person must make, regardless of her or his level of talent. All of us have gifts that are potentially useful and worthy of being appreciated. But to develop these latent talents we must cultivate them, and this takes time and the investment of mental energy. The lifestyle that musically talented students develop can show us some of the choices all of us must make in order to cultivate our gifts.

• Journal of Animal Science and Technology
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• v.53 no.2
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• pp.155-160
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• 2011

Present experiment was carried out to determine maintenance energy requirements for growing Hanwoo steers. Six Hanwoo steers (BW = $180.6{\pm}3.1$ kg) were used in two 3 ${\times}$ 3 latin square design with three different energy intake levels; TDN 1.70 kg (Low), 2.05 kg (Medium), 2.80 kg (High), respectively, based on the Korean Feeding Standards. Each period lasted 18 days including a 14-day adaptation and a 4-day measuring period. The steers were in the head hood chamber system (one cattle per chamber) during each measuring time to measure heat and methane production for 1 day. Dry matter intake was 2,058, 3,256 and 3,881 g/day for Low, Medium and High TDN, respectively. Increase in energy intake did not affect digestibilities of dry matter, crude protein, crude fiber, crude fat, NDF, ADF and nitrogen-free extract. Gross energy intake averaged 180.21, 292.74 and 337.15 kcal/$BW^{0.75}$ for Low, Medium and High TDN, respectively. Energy loss was 28.7% in feces and 2.1% in urine of gross energy intake. Further, energy loss from methane produced during rumen fermentation was 6~8.3%, while body heat loss averaged 34~60%. Intercept of regression equation between ME intake and retained energy indicated that the energy requirement was 109.84 kcal ME/$BW^{0.75}$.

• Journal of Nutrition and Health
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• v.46 no.4
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• pp.346-356
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• 2013

This study investigated the daily physical activity level, energy expenditure, energy balance, and body composition and their relationship with university students. The participants were 130 male students ($19.5{\pm}0.5$ yrs) and 139 female students ($19.5{\pm}0.3$ yrs) at a university in Chungnam province. Physical activity level was evaluated by an equation based on 24 hr-activity record and dietary nutrient intake was evaluated using the food record method during a three-day period consisting of two week days and one weekend. Body composition was measured using Inbody 430 (Biospace Co., Cheonan, Korea). As a result, mean body mass index (BMI) of subjects indicated that they had normal weight, however mean body fat ratio was $19.1{\pm}5.4%$ for males and $28.4{\pm}5.0%$ for females, indicating that they had higher than normal weight. Daily mean physical activity level was 1.55 for males and 1.47 for females, which was regarded as 'low active', respectively. Females had more light activity than males (p<0.01). Daily mean energy expenditure was $2,803.5{\pm}788.9$ kcal/d for males and $1,915.4{\pm}510.2$ kcal/d for females (p<0.001). Daily mean dietary energy intake was $2,327.0{\pm}562.5$ kcal/d for males and $1,802.1{\pm}523.6/d$ for females (p<0.001), and daily mean energy balance was $-476.5{\pm}955.9$ kcal/d for males and $-113.3{\pm}728.1$ kcal/d for females (p<0.01). Daily mean dietary intake of protein, vitamins, and minerals, except Ca, satisfied recommended nutrient intake. Daily energy expenditure was positively related to body weight (p<0.01), BMI (p<0.01), and fat free mass ratio (p<0.05), but was negatively related to body fat ratio (p<0.01). In conclusion, subjects had a negative energy balance and low physical activity. They had a normal weight by BMI but had a more fat than normal weight by body fat ratio. This appears to be related to their low physical activity. Thus, nutrition education should be provided for university students in order to increase their physical activity for maintenance of normal weight by body composition and health promotion.

• Journal of Animal Science and Technology
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• v.49 no.3
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• pp.369-378
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• 2007

Three experiments with different stage of Hanwoo steers (average BW of 167kg, 355kg and 449kg, respectively) were conducted to examine the effect of different quantities of CP intake with similar DM intake on protein balance and N excretion. Twelve Hanwoo steers in each experiment were offered three diets containing three levels of protein (9, 14 and 18% on DM basis) in the concentrate formulated with using different amount of ground corn grain or corn gluten meal. There were significant effects of increasing CP intake on CP digestibility but not on DM digestibility. Despite different CP intake, apparent fecal N outputs were not significantly affected. However, amounts of N excreted into urine increased (p<0.05) with increasing CP intake. There was an obvious effect of live body weight on efficiency of body protein conversion of CP consumed in excess of animal requirement for maintenance, with slopes of 70% and 46~39% for growing and fattening stage, respectively. Nitrogen excretion into feces and urine in this experiment was 70% of the daily N consumption for fattening stage, compared with 60% for growing stage.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.2
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• pp.145-151
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• 1998

The possibility of using rice gruel compared to that of the cane molasses as a source of readily fermentable energy for a urea supplemented straw diet has been studied. Twelve native growing bulls of $237{\pm}8.7kg $ live weight and months old were randomly allocated to three treatments fed solely rice straw enriched with : (1) 3% urea (US), (2) 3% urea + 15% molasses (UMS) and (3) 3% urea + 30% rice gruel (UGS). The feeding trial continued for sixty days. Organic matter (OM) intake was significantly (p < 0.05) higher in the UMS ( $64g/kg\;W^{0.75}/d$) followed by UGS ($53g/kg\;W^{0.75}/d$) and US ($49g/kg\;W^{0.75}/d$). Estimated (from digestible OM intake) metabolizable energy (ME) intake were 396, 348 and $301kJ/kg\;W^{0.75}/d$ for UMS, UGS and US respectively. The maintenance (i.e., no change in live weight) ME intake calculated to be $308{\pm}7.4kJ/kg\;W^{0.75}/d$. Urinary purine derivatives excretion was nonsignificantly higher in the UMS (51.73 mmol/d), followed by UGS (42.53 mmol/d) and US (35.26 mmol/d). The estimated microbial N (MN) yield were 21.10, 14.00 and 11.60 g/d for UMS, UGS and US respectively. For each MJ increase in ME intade, MN yield increased by $1.29{\pm}0.134g$. Observed live weight changes during the experimental period were 292, 125 and -19 g/d respectively for UMS, UGS and US. It was concluded that supplementation of readily fermentable N (urea) alone was not enough to optimize the rumen function and a source of readily fermentable energy was required. Rice gruel was less effective than molasses as fermentable energy source to remove a restriction on voluntary intake and provide less amino acids of microbial origin for absorption from the small intestine, Thus more substrate for protein synthesis and gluconeogenesis were available for growth in the molasses than the rice gruel supplemented animals. However, in situation where molasses is not available or costly, rice gruel does appear to have a place as readily fermentable energy source on a urea supplemented straw diet.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.2
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• pp.209-216
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• 2014

The present study was conducted to estimate the NE values of corn, dried distillers grains with solubles (DDGS) and wheat bran (WB) for laying hens based on an indirect calorimetry method and nitrogen balance measurements. A total of 576 twenty-eight-wk-old Dwarf Pink-shell laying hens were randomly assigned to four groups fed a basal diet (BD) or a combination of BD with 50% corn or 20% DDGS or 20% WB, with four replicates each. After a 7-d adaptation period, each replicate with 36 hens were kept in one of the two respiration chambers to measure the heat production (HP) for 6 days during the feeding period and subsequent 3-d fasting. The equilibrium fasting HP (FHP) provided an estimate of NE requirements for maintenance (NEm). The NE values of test feedstuffs was estimated using the difference method. Results showed that the heat increment that contributed 35.34 to 37.85% of ME intake was not influenced by experimental diets (p>0.05) when expressed as Mcal/kg of DM feed intake. Lighting increased the HP in hens in an fed-state. The FHP decreased over time (p<0.05) with the lowest value determined on the third day of starvation. No significant difference between treatments was found on FHP of d 3 (p>0.05). The estimated AME, AMEn, and NE values were 3.46, 3.44 and 2.25 Mcal/kg DM for corn, 3.11, 2.79, and 1.80 Mcal/kg DM for DDGS, 2.14, 2.10, and 1.14 Mcal/kg DM for WB, respectively. The net availability of AME of corn tended to be numerically higher than DDGS and WB (p = 0.096). In conclusion, compared with corn, the energy values of DDGS and WB were overestimated when expressed on an AME basis.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.3
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• pp.38-51
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• 2020

A bottleneck and congestion occur when a freeway is closed due to maintenance and construction activities on the freeway. Although various traffic managements have been developed to improve the traffic efficiency at freeway work zones, such as merge control, there is a limit to those controls with human drivers. On the other hand, the wireless communication of connected and automated vehicles (CAVs) enables the operation of advanced traffic management. This study developed a traffic control strategy that integrates Dynamic Merge Control (DMC) and Lane Change Control (LCC) in a CAV environment. DMC operates as an either early or late merge based on the occupancy rate of upstream of the work zone. The LCC algorithm determines the number of vehicles that need to change their lane to balance the traffic volume on open lanes. The simulation results showed that integrated control improves the cumulative vehicle count, average speed upstream, and average network travel time.

• The Journal of the Korea Contents Association
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• v.20 no.5
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• pp.437-447
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• 2020

The study was performed to identify the process of change, decisional balance, self-efficacy and social support corresponding to the stage of exercise behavior change and the applicability of social support of women in nursing college based on a Transtheoretical Model. The subjects consisted of 223 women in nursing college by convenience sampling and the data were analyzed by IBM SPSS 21.0 program. The subjects were distributed in each stage of change of behaviors: 17.9% in the precontemplation stage, 54.3% in the contemplation stage, 16.6% in the preparation stage, 4.5% in the action stage and 6.7% in the maintenance stage. Analysis of variance showed that consciousness raising, dramatic relief, self reevaluation, social liberation, counter conditioning, helping relationship, reinforcement management, self liberation, stimulus control, pros, cons and self-efficacy were significantly associated with the stages of exercise behaviors. But there was no significant difference in social support. The transtheoretical model would be applicable to explain the exercise behavior of women in nursing college. This study will be useful information for developing effective exercise programs considering nursing female students' stages of change in exercise behavior.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.12
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• pp.2187-2195
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• 2000

A water treatment system using membrane separation technology can provide stable effluent quality and its maintenance is relatively easy comparing to the conventional water treatment system. In addition, the membrane filtration system is very compact such that it can replace existing water treatment processes of coagulation/sedimentation/filtration by only one process. However, a major problem associated with membrane filtration is flux decline with operating time due to concentration polarization and fouling, so a systematic study on evaluation of long-term filtration performance is necessary. A membrane filtration system using tubular type ultrafiltration membranes with MWCO of 30.000 Da was constructed for this study and it had been operated in a feed-and-discontinuous bleed mode. Flux was stabilized after operation of 1.500 hours and maintaining above 25 LMH until 4.000 hours. Contaminants causing SS and turbidity were almost completely removed while the $UV_{260}$ and DOC removals were 55% and 49%, respectively. A simple mass balance equation was developed to predict maximum concentrations of SS, turbidity, $UV_{260}$ and DOC in a operation cycle. For SS and turbidity the measured max, concentrations in each cycle agree well with the predicted values while the measured max, concentrations of $UV_{260}$ and DOC were 59% and 37% of the predicted values, respectively.