• Journal of Practical Agriculture & Fisheries Research
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• v.16 no.1
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• pp.77-91
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• 2014

This study was performed to provide basal data for effective nutrient control and productivity improvement of the Korean white pine stand. The objectives of this study were to investigate biomass and nutrient distribution in the unthinned Korean white pine plantation which is located in chuncheon, Gangwon province. Aboveground of the stand was estimated by the method of allometric relationship between tree component(kg) and diameter at breast height(DBH, cm). Total above ground biomass of the stand was 127.9t/ha. The relative ratio of stem, living branch, needle compared with total aboveground biomass were 57.9, 16.1, 12.7 and 13.3%, respectively. All nutrients were highly accumulated in needle and N had the largest proportion in the total amount of nutrient accumulation and followed by Ca, K, Mg, P. The amount of nutrient restoration in the Korean white pine was 6,852kg/ha for N, 1,916kg/ha for Ca, 889kg/ha for K, 518kg/ha for Mg, and 124kg/ha for P.

• Journal of Dairy Science and Biotechnology
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• v.28 no.1
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• pp.9-16
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• 2010

Adolescents grow rapidly and have lots of schoolwork for entrance examination, so good nutrition is very important to them. However, adolescents tend to have a poor dietary behavior including frequent consumption of empty calorie foods and skipping breakfast. In particular, frequency of drinking milk has been low among Korean adolescents, thus their dietary calcium intakes has been low. Undesirable dietary behavior of adolescents is a risk factor for poor nutrition, obesity and chronic disease of them. Milk is a good source for calcium, high quality of protein, vitamin and bioactive compounds including anti-obesity component, thus it has been reported that milk helps improvement of dietary nutrient adequacy and physical growth, increment of bone mineral density, and prevention of obesity and chronic diseases. Therefore, milk consumption of adolescents should be encouraged in order to help their nutritional status, physical growth and health.

• Journal of Nutrition and Health
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• v.36 no.8
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• pp.859-869
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• 2003

The purpose of this study was to compare the effects of soup temperature on hunger, energy, and nutrient intake. The hot meal consisted of 400 g of hot beef-vegetable soup (75$^{\circ}C$), Yubu Chobap, Bulgogi, cucumber pickle and radish pickle. The cold meal component were the same as the hot meal except 300 g of water (8$^{\circ}C$) and boiled vegctables (100 g), instead of the hot beef-vegetable soup ot the hot meal. Thirst, core temperature and blood pressure were also measured before and after consumption the test meals in a within-subjects, repeated measures design. 30 women consumed 17% more kilocalories, 13% more protein and lipid and 16% more carbohydrate in the cold meal than in the hot meal. The core temperature at the end of the test meal was higher in the hot meal than in the cold meal. Energy and nutrient intake were inversely correlated with the hunger scores within 1 hour after the hot meal, however those are not related with each other in the cold meal. So hunger feeling might be disturbed in the cold meal. It is concluded that energy and nutrient consumptions were higher in the cold meal, partly because of the distrubed hunger feeling in the cold meal.

• Journal of Nutrition and Health
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• v.37 no.10
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• pp.917-927
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• 2004

This study was performed to examine component of variance in nutrient intakes and to estimate the level of accuracy with varying degree of precision in order to achieve estimates of usual nutrient intakes. Three-day dietary records including both weekdays and weekends were collected every 4 season over a I-year period from 36 males and 93 females aged 40 - 65 y. For each nutrient, we partitioned total intake variance into weekly (weekday vs weekend), seasonal, within- and between- individual variation as components of variance, using analysis of variance. It was found that major components of variance were within- and between-individual variation. Particularly, within-individual variation (57.2 - 87.1 %) was greater than between-individual variation (12.2 - 37.4%) for all nutrients. Weekly and seasonal variation contributed small components of variance for most nutrients. For protein, fat and carbohydrate, there were a little significant weekly variation (0.00 - 1.35%) in females but not in males. For some micronutrients, there were moderately significant seasonal variation (0.15 - 5.48%) in both sexes. Ratio of within- to between- individual variation ranged 1.4 (vitamin B$_2$) -4.5 (vitamin B$_1$) in males and 1.6 (carbohydrate) -2.9 (fat) in females. With total 12-day dietary records data, the maximum percentage deviation of observed intakes from usual (true) intakes ranged 12-37%. To estimate usual individual intakes within 20% of the true mean with 90% confidence level, 3 - 9 days of dietary survey were required for energy, protein, carbohydrate, phosphorus and iron, 13 - 19 days for fat and calcium, 25 - 29 days for vitamin A and vitamin C. Correlation coefficients between observed and true nutrient intakes were 0.71 - 0.91 for males, 0.81-0.91 for females. In conclusion, mean intakes of several nutrients can be reliably measured with the record method, using a limited number of days. Both nutrients of interest and the primary objectives should be taken account when planning method of assessment and number of replicates.

• Environmental Engineering Research
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• v.20 no.4
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• pp.347-355
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• 2015

The growth kinetics of phototrophic microorganisms can be controlled by the light irradiance, the concentration of an inorganic nutrient, or both. A multi-component kinetic model is proposed and tested in novel batch experiments that allow the kinetic parameters for each factor to be estimated independently. For the cyanobacterium Synechocystis sp. PCC6803, the estimated parameters are maximum specific growth rate $({\mu}_{max})=2.8/d$, half-maximum-rate light irradiance $(K_L)=11W/m^2$, half-inhibition-rate light irradiance $(K_{L,I})=39W/m^2$, and half-maximum-rate concentration for inorganic carbon $(K_{S,Ci})=0.5mgC/L$, half-maximum-rate concentration for inorganic nitrogen $(K_{S,Ni})=1.4mgN/L$, and half-maximum-rate concentration for inorganic phosphorus $(K_{S,Pi})=0.06mgP/L$. Compared to other phototrophs having ${\mu}max$ estimates, PCC6803 is a fast-growing r-strategist relying on reaction rate. Its half-maximum-rate and half-inhibition rate values identify the ranges of light irradiance and nutrient concentrations that PCC6803 needs to achieve a high specific growth rate to be a sustainable bioenergy source. To gain the advantages of its high maximum specific growth rate, PCC6803 needs to have moderate light illumination ($7-62W/m^2$ for ${\mu}_{syn}{\geq}1/d$) and relatively high nutrient concentrations: $N_i{\geq}2.3 mgN/L$, $P_i{\geq}0.1mgP/L$, and $C_i{\geq}1.0mgC/L$.

• Ocean and Polar Research
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• v.38 no.1
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• pp.1-19
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• 2016

Recently, there has been a growing interest in physical-biological ocean-modeling systems by communities in the fields of science and business. In this paper, we present preliminary results from a coupled physical-biological model for the Northwestern Pacific marginal seas. The ocean circulation component is an implementation of the Regional Ocean Modeling System (ROMS), and the lower trophic level ecosystem component is a Nutrient-Phytoplankton-Zooplankton-Detritus (NPZD) model. The ROMS-NPZD coupled system, with a 25 km resolution, is forced by climatological atmospheric data and predicts the physical variables and concentrations of nitrate, phytoplankton, zooplankton, and detritus. Model results are compared with remote-sensed sea surface temperature and chlorophyll, and with climatological sea surface salinity and nitrate. Our model adequately reproduces the observed spatial distribution and seasonal variability of nitrate and chlorophyll concentrations as well as physical variables, showing a high correlation in the East Sea (ES) and Kuroshio/Oyashio Extension (KOE) region but relatively low correlation in the Yellow Sea (YS) and East China Sea (ECS). Although some deficiencies were found in the biological components, such as the over/underestimation of the intensity of phytoplankton blooms in the ES and KOE/the YS and ECS, our system demonstrates the capability of the model to capture and record dominant seasonal variability in physical-biological processes and this holds out the promise of coming to a better understanding of such processes and making better predictions .

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.328-335
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• 2023

For appropriate nutrient management and enhanced plant growth, soil sensors which reflect soil nutrient levels are required. Because there is no available sensor for nutrient monitoring, electrical conductivity (EC) sensor can be used to evaluate soil nutrient levels. Soil nutrient management using EC sensors would be possible by understanding the relationship between sensor EC values and soil temperature, moisture, and nutrient content. However, the relationship between soil sensor EC values and plant available nutrients was not investigated. Therefore, the objectives of the study were to evaluate effect of different amount of urea on soil EC monitored by sensors during pepper and broccoli cultivation and to predict the plant available nutrient contents in soil. During the cultivation period, soil was collected periodically for analyzing pH and EC, and the available nutrient contents. The sensor EC value increased as the moisture content increased, and low fertilizer treated soil showed the lowest EC value. Principal component analysis was performed to determine the relationship between sensor EC and available nutrients in soil. Sensor EC showed a strong positive correlation with nitrate nitrogen and available Ca. In addition, sum of available nutrients such as Ca, Mg, K, P, S and N was positively related to the sensor EC values. Therefore, EC sensors in open field can be used to predict plant available nutrient levels for proper management of the soil.

• Journal of the Korean Dietetic Association
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• v.8 no.1
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• pp.9-18
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• 2002

This study was reviewed databases and outcomes of national/international off-line and on-line(Internet) nutrition softwares to identify the present conditions of nutrition softwares, and investigated user's needs and determine which component should be included in nutrition software. The most frequently used databases for the national programs were the food composition table provided from the National Rural Living Science Institution in Rural Development Administration and the food composition table and the nutrient contents of foods provided from the Korean Nutrition Society. For international programs, the food composition table from the USDA was commonly used. The analysed outcomes included the degree of obesity, nutrient analysis and nutrient intake compared with RDA, food intake from each by food group, food habits and the frequency of food consumption. As to the result of needs assessment for the Internet nutrition softwares, it was suggested that the needs of the Internet nutrition softwares were high because most of the respondents replied that 3-point('it is needed') or 4-point('it is necessary') on 4-points likert scale. As to the databases, the needs of 'food composition analysis' and 'the suggestion of the Korean RDA' were high. For the basic information for foods, the respondents replied that 'the classification of foods', 'foods codes', 'the amount of ingredients' and 'nutrient analysis' should be included. The needs of 'nutrient analysis of meal', 'diet therapy' and 'meal plan by caloric requirements' were high. As for utilizing the Internet meal planning programs, the respondents replied that 'it should be easy to use' most and demand for 'data saving and the saved data should be usable later' and 'meal planning education tools' were high. In conclusion, the Internet nutrition software that satisfies various needs of users should be developed for policy making that promote public health, nutritional care and self-supporting of foods.

• Journal of Environmental Science International
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• v.11 no.6
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• pp.519-528
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• 2002

This study was to evaluate the impact of river runoff and salt intrusion by tide on nutrient balance of estuary during a complete tidal cycle. 24 hours time series survey was carried out during a spring tide July 2001 on a tidal estuary in the Keum river. Three stations(A,B,C) were set along a transect line of about 10km, which linked the lower part of estuary dyke to the subtidal zone. Surface water was sampled simultaneously at each station every hours f3r the determination of nutrients. Water temperature, pH and dissolved oxygen were measured in situ. Riverine input of silicate and nitrate during ebb tide significantly increased the concentration of all stations. Conversely, during high tide, nutrient concentration were lowered by the mixing of fresh water with sea water Ammonium nitrogen concentration were higher at intertidal zone(Stn.B) due to sewage inflow to Kyeongpo stream and ammonium release under anaerobic conditions. Also, these results was discussed as a biological component that influences the processes of nutrient regeneration within the estuary. Best correlations were found at lower part of estuary dyke(Stn.A) for salinity against DIN(Y=0.121 Sal.+4.97, r2=0.956) and silicate(Y=0.040 Sal.+2.62, r2=0.785). But no significant correlation was found between salinity and ammonium. Unbalanced elemental ratio(N/P, Si/N and Si/P) depended significantly on the import of nutrients (silicate & nitrate nitrogen) from river and stream. The effect of the tidal cycle and river runoff is important that in determining the extend of the variations in nutrient concentrations at all station.

• The Korean Journal of Ecology
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• v.27 no.2
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• pp.115-120
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• 2004

Coarse woody debris (CWD, $\ge$ 5 cm in maximum diameter) is an important functional component, especially to nutrient cycling in forest ecosystems. To compare mass and nutrient dynamics of CWD in natural oak forests, a two-year study was conducted at Quercus serrata and Q. variabilis stands in Yangpyeong, Kyonggi Province. Total CWD (snag, stump, log and large branch) and annual decomposition mass (Mg/ha) were 1.9 and 0.4 for the Q. serrata stand and 7.5 and 0.5 for the Q. variabilis stand, respectively. Snags covered 72% of total CWD mass for the Q. variabilis stand and 42% for the Q. serrata stand. Most of CWD was classified into decay class 1 for both stands. CWD N and P concentrations for the Q. variabilis stand significantly increased along decay class and sampling time, except for P concentration in 2002. There were no differences in CWD N concentration for the Q. serrata stand along decay class and sampling time. However, CWD P concentration decreased along sampling time. CWD N and P contents (kg/ha) ranged from 3.5∼4.7 and 0.8∼1.3 for the Q. serrata stand to 22.8∼23.6 and 3.7∼4.7 for the Q. variabilis stand. Nitrogen and P inputs (kg/ha/yr) into mineral soil through the CWD decomposition were 0.7 and 0.3 for the Q. serrata stand and 1.6 and 0.3 for the Q. variabilis stand, respectively. The number of CWD and decay rate were main factors influencing the difference in CWD mass and nutrient dynamics between both stands.