• Journal of Bio-Environment Control
• /
• v.1 no.2
• /
• pp.162-168
• /
• 1992

As the automation of nutrient solution management proceeds in the field of hydroponics, effective supporting systems to manage the nutrient solution by computer become needed. This study was attempt to predict the EC of nutrient solution using the neural networks. The multilayer perceptron consisting of 3 layers with the back propagation learning algorithm was selected for EC prediction, of which nine variables in the input layer were the concentrations of each ion and one variable in the output layer the EC of nutrient solution. The meq unit in ion concentration was selected fir input variable in the input layer. After the 10,000 learning sweeps with 108 sample data, the comparison of predicted and measured ECs for 72 test data showed good agreements with the correlation coefficient of 0.998. In addition, the predicted ECs by neural network showed relatively equal or closer to the measured ones than those by current complicated models.

• Korean Journal of Community Nutrition
• /
• v.6 no.3
• /
• pp.516-526
• /
• 2001

Working towards the compression of morbidity, we attempted to find the way to contribute to desirable aging and/or healthy old age. By looking into the factors affecting nutrient intake in middle-aged adults, we sought to find ways to improve their health status, Two hundred and fifty middle-aged adults from 40 to 60 years of age residing in Seoul and its vicinity were recruited for the survey. Subjects were interviewed for general characteristics, dietary habits lifestyle, status and food intake by a trained interviewer. Two -day food record was included in addition to the 1 -day 24 hr recall. Date were analyzed for the relationship among nutrient intake, health status, socio-economic status dietary habits and lifestyle using a statistical program (SAS) Although the mean energy intake of the subjects did not reach the recommenced dietary allowances(RDA), mean protein intake was well above the RAD for both sex groups(111.2% and 129.1% for men and women, respectively) The caloric contribution of fat was 15 to 20 % of total energy intake among different groups. Riboflavin was the most deficient nutrient and its mean intake reached only 71.0% of RDA for mean This seemed to be due to the lower intake of milk and dairy products among middle-aged Koreans who are more accustomed to traditional meals. Income and exercise habit were the most important factors influencing the nutrient intake of middle-age adults. Also, BMI, smoking habit, level of education regularity of meal, and hours of sleeping influenced the nutrient intake, In conclusion, middle-age adults appeared to have similar problems with the elderly in terms of nutrient intake and this age group should to included when considering nutritionally vulnerable groups in addition to the elderly and young children. The improvement in the nutrition status of middle-age adults is even more important because that could lead into the better health the elderly.

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.8
• /
• pp.1158-1164
• /
• 2003

In two feeding experiments male and mixed-sex broiler chicks were offered diets based on sorghum and a wheatsorghum blend with two tiers of nutrient specifications, without and with microbial phytase (600 and 800 FTU/kg), from 7-25 and 1-42 days post-hatch, respectively. The nutrient specifications for protein, amino acids, energy density and phosphorus (P) of standard diets were reduced to formulate the modified diets on a least-cost basis. Calculated differences in nutrient specifications between standard and modified diets ranged from 14.3 to 17.1 g/kg crude protein, 0.24 to 0.40 MJ/kg apparent metabolisable energy (AME) and 1.06 to 1.20 g/kg available P. In both experiments, reduced nutrient specifications had a negative impact on growth rates and feed efficiency and phytase supplementation had a positive influence on growth performance and protein efficiency ratios (PER). Phytase addition to the less expensive, modified diets either partially or entirely compensated for reduced growth performance and, consequently, feed costs per kg of live weight gain were reduced. In Experiment 1, phytase increased (p<0.001) nitrogen-corrected AME (AMEn) from 15.39 to 15.89 MJ/kg dry matter. For nitrogen (N) retention there was an interaction (p<0.05) between diet type and phytase as the effects of phytase on N retention were more pronounced in the modified diets, with an increase from 0.512 to 0.561. These results demonstrate the positive effects of phytase on protein and energy utilisation, in addition to its established liberation of phytate-bound P and illustrate the feasibility of assigning nutrient replacement values to the feed enzyme for consideration in least-cost ration formulations. Further work is, however, required to define the most appropriate reductions in nutrient specifications in association with phytase supplementation.

• Journal of the Korean Society of Food Culture
• /
• v.29 no.6
• /
• pp.659-667
• /
• 2014

Fruits are good sources of vitamins, minerals, fiber, and phytochemicals, which are known to reduce serum lipids, oxidative damage, and blood pressure as well as improve blood glucose control. The purpose of this study was to estimate nutrient quality indices of fruits by carrying out a critical analysis of pre-existing methods according to their nutritional compositions. Four methods were used to assess the nutrient indices of 26 fruits, which are frequently consumed by Koreans based on the fourth Korean National Health and Nutrition Examination Survey (2009). Naturally nutrient rich score (NNR), nutrient rich food (NRF), nutrient adequacy score (NAS), and nutrient density score (NDS) were used to calculate nutrient quality indices. The Korean Nutrition Society Food Composition database of fruits based on 100 g edible portions was used. The algorithm of each method included the mean percentage of daily values (Dietary Reference Intakes for Koreans, 2010) for particular nutrients based on consumption of 1,900 kcal/day. The relative score indicated that strawberries, kumquat, and lemon had high nutrient quality indices. In addition, mango, lemon, persimmon, strawberry, apricot, and tangerine fruits are rich in antioxidant nutrients such as ${\beta}$-carotene, vitamin C, vitamin E, and selenium. However, scores of nutrient quality indices did not imply that higher scores of particular fruits are superior. We suggest moderate seasonable consumption a variety of fruits. Our results can be used as a reference for consumers when they choose fruits.

• The Korean Journal of Ecology
• /
• v.23 no.2
• /
• pp.169-173
• /
• 2000

Seasonal distribution of ectomycorrhizal associations in various types of forest in a boreal forest in Manitoba. Canada was investigated. Alsohe relationship between ectomycorrhizal growth and pine pollen nutrients was examined. In four different forest stands, ectomycorrhizas tended to be lower in the spring than in the summer and fall samples. In addition. a mature jack pine (Pinus banksiana) stand showed higher mycorrhizal activities than a young jack pine stand. Growth of Suillus brevipes hyphae wa ts stimulated by additions of pollen representing mean pollen deposition in Mistik Creek study area after 30 and 70 days of growth with dextrose availability. This result suggests that the peak ectomycorrhizal activity is followed by pollen deposition in the study region and therefore, addition of pine and spruce pollen in early or middle of June in the boreal forest can be an important seasonal nutrient source for ectomycorrhizal growth.

• Journal of Korean Society on Water Environment
• /
• v.28 no.5
• /
• pp.663-668
• /
• 2012

The feasibility of enhancing biological nutrient removal from an industrial wastewater was tested with food waste leachate and sugar liquid waste as external carbon sources. Long term influences of adding external carbon sources were investigated to see how the biological nutrient removal process worked in terms of the removal efficiency. The addition of the external carbons led to a significant improvement in the removal efficiency of nutrients: from 49% to approximately 76% for nitrogen and from 64% to around 80% for phosphorus. Approximately, 20% of the removal nitrogen was synthesized into biomass, while the remaining 80% was denitrified. Though the addition of external carbon sources improved nutrient removal, it also increased the waste sludge production substantially. The optimal observed BOD/TN ratio, based on nitrogen removal and sludge production, was around 4.0 in this study.

• Korean Journal of Community Nutrition
• /
• v.4 no.1
• /
• pp.74-82
• /
• 1999

This study evaluated the quality of meals served by the elementary schools in Muan based on nutrient contents and food diversity. The contents, nutrient densities and nutrient adequacy ratios(NAR) of most nutrients were higher than those calculated from the Korean RDA. However, the content, nutrient density, and NAR of iron were lower than those calculated from the RDA for 10 to 12 year old girls. The content of sodium was somewhat high. The average number of different kinds of food and dishes per meal were 19.2 and 6.0, respectively. The more the number of dishes, the higher the NARs of calcium, calories, niacin, phosphorus and protein. However, the NAR of iron showed no correlation with the number of dishes. The meals belonging to the food group intake pattern containing fruits had more vitamin C and fiber, and less protein, lipid, and phosphorus than those belonging to the food group intake pattern not containing fruits. In conclusion, the quality of nutrition of meals served by school lunch program(SLP) was considered fairly good. However, the nutritionists should consider the iron for 10 to 12 year old girls and cut down the amount of sodium. In addition, unless the children prefer the foods served by SLP or adjust to the general aspects of SLP, SLP can't accomplish its purposes. Therefore, we suggest that nutritionists should survey children's food preference and satisfaction with the general aspects of SLP.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.53 no.1
• /
• pp.63-69
• /
• 2011

The green algae Scenedesmus acuminatus was cultured in different media: animal wastewater and an artificial culture medium in order to evaluate potential use for tertiary treatment. The experiments were conducted with air flowrate 1~2 L/min at $28{\sim}30^{\circ}C$. The nitrogen and phosphorus showed very similar removal efficiencies (68~77 % and 69~80 % for nitrogen and phosphorus respectively). The optimal fed period was estimated as three days in the semi-continuous experiment. The effects of $CO_2$ (4.5 %) injection on nutrient uptake from animal wastewater (biological treatment effluent) were compared to an air injection under the same conditions of light and photoperiod. The uptake rates of nutrient with air injection were observed 0.009 gN/gChl-a/day, 0.028 gN/gChl-a/day and T-P 0.003 gP/gChl-a/day for nitrate, total nitrogen and phosphorus respectively. The rates were enhanced by addition of $CO_2$ to 0.026 gN/gChl-a/day, 0.076 gN/gChl-a/day and T-P 0.018 gP/gChl-a/day. This study establishes that $CO_2$ addition during nutrient deprivation of microalgal cells may accelerate tertiary wastewater treatment.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.11
• /
• pp.186-195
• /
• 2016

We investigated phytoplankton and vertical inorganic nutrients at two stations around water of Ulleungdo and Dokdo in the East Sea, Korea. Nutrient addition experiments (+N, +P, +NP and +Fe) were also conducted to determine the growth response and nutrient consumption of the phytoplankton assemblage using the surface water of St. UD3 and St.50. In the field, although inorganic nutrients were low in the euphotic layer, these nutrients were increased at depths below 100 m. The total phytoplankton abundances in St. UD3 and St.50 were $4.9{\times}10^5cells\;L^{-1}$ and $1.9{\times}10^5cells\;L^{-1}$, respectively. The dominant species at St. UD3 was observed to be Raphidophyta Heterosigma akashiwo, Cryptophyta Crytomonas spp., and diatom Leptocylindrus danicus, while L. danicus and H. akashiwo including small diatom species Chaetoceros socialis were dominant at St. 50. In the nutrient addition experiments, phytoplankton growth (in vivo flourescence) in the +N and +NP treatment was 2-3 times higher than that in the +P treatment, indicating that the natural phytoplankton can respond to pulsed nutrient loading events. In addition, in vivo fluorescence in +Fe treatment was not statistically (p>0.05) different from that of the non-Fe treatments, indicating that the phytoplankton growth response in +Fe treatment was not significant. Dominant H akashiwo and L. danicus in the field showed a rapid response in nutrient additional bio-algal assay, particularly L. danicus in the +Fe treatments.

• Korean Journal of Community Nutrition
• /
• v.6 no.4
• /
• pp.645-656
• /
• 2001

The relationship between socio-economic status and food and nutrient consumption patterns was studied in 7,370 Koreans aged 20 years and older in the 1995 Korean Health and Nutrition Survey. The aim of this study was to investigate the effect of rapid economic growth on food and nutrient consumption for Korean adults in the last 30 years. Monthly household income, and individual's educational level and occupation were chosen as variables of socio-economic status for individuals. A one day 24 hour recall method was used for the dietary survey. One way analysis of varience was adopted to test tole association between socio-economic variables and food and nutrient consumption patterns. Individuals who had a high socio-economic status had significantly higher daily intake of most of the nutrients including calcium, vitamin A, vitamin B$_2$which reached above the recommended dietary allowances(RDA) and a higher percentage energy consumption from fat. In addition, individual who belonged to a low socio-economic status consumed less animal foods, including meat, egg, milk and consumed low proportion of energy from fat. The results suggest that in spite of rapid economic growth during the last 30 years in Korea, individuals who belonged to low sorio-economic status categories are still nutritionally vulnerable. Among the sorio-economic variables, income and education except occupation were the influential factors on the food and nutrient consumption of Koreans. Therefore, nutrition policy should focus on influencing the dietary patterns of lower social class individuals to improve the health status of the population as a whole.