• Korean Journal of Ichthyology
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• v.19 no.4
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• pp.306-317
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• 2007

Reproductive cycle with the gonad developmental phases, first sexual maturity, spawning frequency, sex ratio of the dusky mud hopper, Periophthalmus modestus were investigated by histological observations. Monthly variations of the gonadosomatic index (GSI) began to increase in May and reached a maximum in June when the gonad was getting mature during the period of higher ground (water) temperature-long day length. Changes in the GSI showed a negative correlation to the HSI, but coincided with the fatness index. The reproductive cycle can be classified into five successive stages: in female, early growing stage (April to May), late growing stage (April to May), mature stage (May to June), ripe and spent stage (June to August), and recovery and resting stage (August to March); in males, growing stage (April to May), mature stage (May to June), ripe and spent stage (June to August), and recovery and resting stage (August to March); According to the frequency distributions of egg diameters during the breeding season, Periophthalmus modestus is presumed to be a summer breeder, asynchronous group and polycyclic species to spawn 2 times or more during the spawning season. Total eggs and mature eggs in absolute fecundity and relative fecundity (per cm) increased with the increase of body length. Total eggs and mature eggs in absolute fecundity and relative fecundity (per g) did not increase with the increase of body weight. Percentages of first sexual maturity of females and males ranging from 5.1 to 5.5 cm in body length are over 50%, and 100% for fish over 7.1 cm in body length. The sex ratios of females to males over 5.1 cm in body length were not significantly different from a 1 : 1 sex ratio.

• Korean Journal of Poultry Science
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• v.31 no.4
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• pp.273-281
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• 2004

A feeding trial was conducted with Euglena strains grown under different media. The effect of supplementation of Euglena on the performance, nutrient availability and fatty acid composition of breast muscle was studied. In experiment I, two hundred ten hatched broiler chicks (Ross) were assigned to seven dietary treatments for 5 weeks. Each treatment consisted of 3 replications with 10 birds each. Control diet was formulated to have $22\%$ CP and 3,150 kcal ME/kg for starter diet, $19\%$ CP and 3,200 kcal ME/kg for finisher diet. Euglena gracilis Z. (EG) was added to control diet at the plevel of 0.25, 0.5, $1.0\%$ and Euglena gracilis Z. bleached and DHA enriched (EGBD; a strain mutated by streptomycin and cultivated in DHA enriched medium) at the level of 0.5, 1.0, $2.0\%$ in the diet. In experiment 2, two hundred fifty hatched broiler chicks (Ross) were assigned to five dietary treatments: T1; Control, T2; T1 + Euglena gracilis Z. DHA enriched (EGD; cultivated in DHA enriched medium) $0.5\%$, T3; T1 + EGD $1.0\%$, T4; T1 + EGBD $0.5\%$, T5; T1 + EGBD $1.0\%$. The weight gain and feed consumption were measured weekly. Fatty acid composition of breast muscle was determined. In experiments I and 2, Euglena supplementation had no significant effects on weight gain, feed intake and feed conversion ratio. In experiment 1, EGBD treatments significantly increased DHA concentration but decreased concentration of linoleic acid and arachidonic acid in breast muscle. EGBD 2% treatment showed the highest DHA concentration (14.27%) which is 3.9 times of that of the control ($3.66\%$). In experiment 2, $1.0\%$ EGBD treatment showed highest EPA, lignoceric acid and DHA level in breast muscle (P<0.05). Also, EGD treatments significantly increased DHA and EPA concentration. It was concluded that EGBD and EGD can be supplemented to broiler diet to produce DHA enriched broiler meat.

• Journal of Korean Society of Forest Science
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• v.53 no.1
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• pp.1-26
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• 1981

1. Aiming at supply of basic informations on tree species siting and forest fertilization by understanding of soil properties that are demanded by each tree species through studies of forest soil's morphological, physical and chemical properties in relation to tree growth in our country, the necessary data have been collected in the last 10 years, are quantified according to quantification theory and are analyzed in sccordance with multi-variate analysis. 2. Test species, japanese larch (Larix leptolepis Gord) and the Korean white pine, (pinus koraiensis S et Z.) are plantable in extensive areas from mid to north in the temperate forest zone and are the two most recommended reforestation tree species in Korea. However, their respective site demands are little known and they have been in confusion or considered demanding the same site during reforestation. When the Korean white pine is planted in larch sites, it has shown relatively good growth, but, when Japanese larch is planted in Korean white pine site it can be hardly said that the Japanese Larch growth is good. To understand on such a difference soil factors have been studied so as to see how th soil's morphological, physical and chemical factors affect tree growth helped with the electronic computer. 3. All the stands examined are man-made mature forests. From 294 Japanese larch plots and 259 Korean white pine plots dominant trees are cut as samples and through stem analysis site index is determined. For each site index soil profiles are made in the related forest-land for analysis. Soil samples are taken from each profile horizon and forest-land productivity classification tables are worked out through physical and chemical analyses of the soil samples for each tree species for the study of relationships between physical, chemical and the combined physical/properties of soil and tree growth. 4. In the study of relationships between physical properties of soil and tree growth it is found out that Japanese larch growth is influenced by the following factors in the decreasing order of weight deposit form, soil depth, soil moisture, altitude, relief, soil type, depth a A-horizon, soil consistency, content of organic matter, soil texture, bed rock, gravel content, aspect and slope. For the Korean white pine the influencing factors' order is soil type, soil consistency, bed rock, aspect, depth of A-horizon, soil moisture, altitude, relief, deposit form, soil depth, soil texture, gravel content and slope. 5. In the study of relationships between chemical properties of soil and tree growth it is found out that Japanese larch growth is influenced by the following factors in the order of base saturation, organic matter, CaO, C/N ratio, effective $P_2O_5$, PH, exchangeable, $K_2O$, T-N, MgO, CEC, Total Base and Na. For the Korean white pine the influencing factors' order is effective $P_2O_5$, Total Base, T-N, Na, C/N ratio, PH, CaO, base saturation, organic matter, exchangeable $K_2O$, CEC and MgO. 6. In the study of relationships between the combined physical and chemical properties of soil and tree growth it is found out that Japanese larch growth is influenced by the following factors in the order of soil depth, deposit form, soil moisture, PH, relief, soil type altitude, T-N, soil consistency, effective $P_2O_5$, soil texture, depth of A-horizon, Total Base, exchangeable $K_2O$ and base saturation. For the Korean white pine the influencing factors' order is soil type, soil consistency, aspect, effective $P_2O_5$, depth of A-horizon, exchangeable $K_2O$, soil moisture, Total Base, altitude, soil depth, base saturation, relief, T-N, C/N ratio and deposit form. 7. In the multiple correlation of forest soil's physical properties larch's correlation coefficient for Japanese Larch is 0.9272 and for Korean white pine, 0.8996. With chemical properties larch has 0.7474 and Korean white pine has 0.7365. So, the soil's physical properties are found out more closely related with tree growth than chemical properties. However, this seems due to inadequate expression of soil's chemical factors and it is proved that the chemical properities are not less important than the physical properties. In the multiple correlation of the combined physical and chemical properties consisting of important morphological and physical factors as well as chemical factors of forest soils larch's multiple correlation coefficient is found out to be 0.9434 and for Korean white pine it is 0.9103 leading to the highest correlation. 8. As shown in the partial correlation coefficients Japanese larch needs deeper soil depth than Korean white pine and in the deposit form of colluvial and creeping soils are demanded by the larch. Moderately moist to not moist should be soil moisture and PH should be from 5.5 to 6.1 for the larch. Demands of T-N, soil texture and soil nutrients are higher for the larch than the Korean white pine. Thus, soil depth, deposit form, relief, soil moisture, PH, N, altitude and soil texture are good indicators for species sitings with larch and the Korean white pine while soil type and soil consistency are indicative only limitedly of species sitings due to their wide variations as plantation environments. For the larch siting soil depth, deposit form, relief, soil moisture, pH, soil type, N and soil texture are indicators of good growth and for the Korean white pine they are soil type, soil consistency, effective $P_2O_5$ and exchangeable $K_2O$. In soil nutrients larch has been found out demanding more than the Korean white pine except $K_2O$, which is demanded more by the Korean white pine than Japanese larch generally. 9. Physical properties of soil has been known as affecting tree growth to the greatest extent so far. However, as a result of this study it is proved through computer analysis that chemical properties of soil are not less important factors for tree growth than chemical properties and site demands for the Japanese larch and the Korean white pine that have been uncertain so far could be clarified.

• Food Science and Preservation
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• v.23 no.7
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• pp.1065-1073
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• 2016

This study investigated the sensory attributes and quality characteristics of Fuji apples based on market commodity price to provide data for quality index of Fuji apples. Samples were purchased from the Garak market (Seoul Agro-Fisheries & Food Corporation) and divided into four groups depending on the price such as group A, B, C, D. There were no significant differences in their volume and weight among groups. In the soluble solid content and total free sugar, A and B group (high price) showed higher content than those of C and D (low price) group. And also, the A group and B, C, D group showed 386.29 mg% and 320.09~359.28 mg% in the total organic acid content, respectively. As an sensory evaluation results, A group and B group were evaluated higher score than those of C and D group in the uniformity of red color and glossiness of skin and unique apple sensory attributes using quantitative descriptive analysis. Consumer test showed similar to quantitative descriptive analysis results in the various sensory attributes. In the analysis results between quality characteristics and sensory attributes of Fuji apples, total acceptability was correlated positively with titratable acidity (r=0.58), soluble solid (r=0.89), soluble solid content/titratable acidity ratio (r=0.42), total free sugar (r=0.36) and total organic acid (r=0.38). Based on principal component analysis of apple's quality characteristics, apples were primary separated along the first principal component (pH, acidity, soluble solid content, total free sugar, organic acid), which accounted for 66.01% of total variance. In addition, principal component analysis of sensory evaluation revealed a total variance for the quantitative descriptive of 55. 65% and a total variance for the consumer test of 55.84%.

• Journal of The Korean Society of Grassland and Forage Science
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• v.1 no.1
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• pp.18-28
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• 1978

To study about the effect of harvested stage and physical treatment such as wilting or chopping of plant material on the quality of silage, Italian ryegrass(Lolium multiflorum) harvested at pre-headed or heading stage and Seombadi(Dystaenia takesimana Nakai) harvested at pre-flowering stage, were used for the purpose. The materials were treated in four different ways which were a) non-treated, b) one day-wilted, c) chopped with 1 to 2cm length and d) wilted and chopped, and those were ensiled in plastic containers and stored at room temperature for three months. After three months of storage, it was investigated and obtained the following results. 1) Having 6.31 of NFE/CP ratio and low content of crude fiber, Seombadi contained more suitable constituents for silage than Italian ryegrass. 2) Under the non-treated or chopped condition, the loss of NFE was higher, and lower with wilted material. 3) Wilting or chopping improved DM digestibility. 4) Compared with Italian ryegrass harvested at pre-headed stage, the storage amount per unit volume of heading stage-Italian ryegrass and Seombadi were higher 8% and 69% respectively, and wilting and/or chopping increased the storage amount 41 to 134%. 5) The majority of weight loss during storage was observed at 1st week after ensiling, it continued slightly until 4th week. The highest loss in 8th week were 3.76% of nontreated material. 6) One day wilting increased DM content of silage 23 to 131%. Wilting and chopping increased pH and lactic acid improved the quality considerably. 7) The correlation between $NH_3$ and butyric acid, and between lactic acid and DM were r=0.782**, r=0.634** respectively. The regression equation were y=12.853X+4.908 (X=butyric acid), y=0.016X+1.309(X=DM content), respectively. 8. The above results indicate that it is necessary to wilt or chop material to make good quality silage from Italian ryegrass, and such treatment can improve the quality of silage with Seombadi also.

• Journal of Aquaculture
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• v.21 no.2
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• pp.82-88
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• 2008

A 12-week feeding trial was conducted to investigate the effects of dietary supplementation of probiotics as a feed additive for juvenile Korean rockfish Sebastes schlegeli. Four experimental diets supplemented with no probiotic(Control), Bacillus polyfermenticus(BP), Bacillus licheniformis(BL) or Bacillus polyfermenticus plus Saccharomyces cerevisiae(BP+SC) at $1.0{\times}10^7$ CFU/kg diet as a dry-mater(DM) basis were prepared by mixing with a basal diet. After 12 weeks of the feeding trial, fish fed BP+SC diet showed significantly higher weight gain(WG), feed efficiency(FE), specific growth rate(SGR) and protein efficiency ratio(PER) than those of fish fed control diet(P<0.05), however there were no significant differences in WG, FE, SGR and PER among fish fed the BP, BL and BP+SC diets. Fish fed BP and BP+SC diets showed significantly higher condition factor(CF) than that of fish fed control and BL diets. Fish fed BP, BL, BP+SC diets showed significantly higher hepatosomatic index(HSI) than that of fish fed control diet, however there was no significant difference in HSI among fish fed BP, BL and BP+SC diets. Fish fed BP+SC diet showed significantly lower serum glucose than that of fish fed control diet, however there was no significant difference in serum glucose among fish fed BP, BL and BP+SC diets. Fish fed BP+SC diet showed significantly higher respiratory burst activity(NBT assay) than that of the fish fed control and BL diets, however there was no significant difference in NBT assay between fish fed BP and BP+SC diets. Fish fed BP and BL diets showed significantly higher lysozyme activity than that of the fish fed control diet, however there was no significant difference in lysozyme activity among fish fed BP, BL and BP+SC diets. Fish fed BP and BP+SC diets showed significantly lower cumulative mortality than that of the fish fed control diet, however there was no significant difference in cumulative mortality among fish fed BP, BL and BP+SC diets after the challenge test. From these results, dietary B. polyfermenticus, B. licheniformis and B. polyfermenticus plus S. cerevisiae supplementation in juvenile Korean rockfish diet could enhance growth performances, non-speicific immunities and a higher resistance against the specific pathogen.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.6
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• pp.694-708
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• 2009

The principal objective of this study was to determine the effects of smoking & drinking on the diet, nutrient intake, and overall health. A sample of 262 youths, aged 16 to 18 year-old, was randomly selected from Seoul and its vicinity. The subjects participated by answering survey questions including general questions, questions regarding health, smoking & drinking habits, dietary habits, nutrient intake, physical characteristics, and smoking cessation plans. The average height, weight, and BMI of the subjects were $173.5{\pm}6.8\;cm$, $64.8{\pm}11.8\;kg$, and $21.4{\pm}3.7\;kg/m^2$, respectively. Among the subjects, 88% appeared to be interested in health and 43.5% of youth asserted that the best way to keep healthy was to engage in regular exercise. Among 63 smokers, 52 students (82.5%) used alcoholic beverages while 11 students (17.5%) did not use alcoholic beverages, meaning that smoking was a causative factor in drinking. 55.6% of youth reported beginning to smoke in middle school, and 38.1% of them asserted that curiosity was the motive for smoking. The youth reported that the craving for smoking was highest when hungry, and the best place to smoke was the restroom. 20 students (69.0%) answered that the only way to quit smoking was just to stop. 12 students (44.4%) reported that the main reason for failures in smoking cessation attempts was a lack of intention or willpower. 87.1% of all subjects answered that they were inclined to quit smoking, and 56.7% of them would be interested in attending a smoking cessation program if they had the opportunity. Among the smoking and drinking group, 50% of drinkers began to drink in high school, and the reason for drinking given was peer pressure-40% of drinkers answered that they wished to quit drinking. 34.4% of students appeared to have breakfast everyday, but 16.4% of students answered that they had quit eating breakfast. 52.5% of all students reported that the principal reason for overeating was the presence of one's favorite food, and the smoking and drinking group reported overeating more frequently than other groups (p<0.05). 72.6% of all subjects reported eating interim meals $1{\sim}2$ times daily, 36.4% of smokers ate carbonated beverages, 38.5% ate ice cream as a interim meal, and 38.5% of the drinking and smoking groups ate fruits, 26.9% of them ate fried foods, and some of them ate fast foods as a interim meal. Among smokers, the ratio of eating fat-rich foods, and meats such as kalbi and samgyupsal more than two times per week was higher, and 54.3% of smokers ate ice cream, cookies, and carbonated beverages more than two times per week (p<0.05). The total nutrient intake of the $15{\sim}19$-year youth group was much higher than the standard value. The energy intake of the smoking group and the drinking and smoking group was significantly higher than that of the normal group (p<0.05). Intakes of phosphorus (p<0.05), cholesterol (p<0.05), and sodium (p<0.05) were the highest among all groups. Accordingly, it is recommended that practical education programs be implemented to teach young students to resist peer pressures to smoke and drink. Additionally, education that acknowledges the importance of nutrition is necessary to avoid preferential eating and overeating due to smoking and drinking.such education can also teach students to eat a balanced diet and improve their physical development.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.469-484
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• 2021

Rock mass classification results have a great influence on construction schedule and budget as well as tunnel stability in tunnel design. A total of 3,526 tunnels have been constructed in Korea and the associated techniques in tunnel design and construction have been continuously developed, however, not many studies have been performed on how to assess rock mass quality and grade more accurately. Thus, numerous cases show big differences in the results according to inspectors' experience and judgement. Hence, this study aims to suggest a more reliable rock mass classification (RMR) model using machine learning algorithms, which is surging in availability, through the analyses based on various rock and rock mass information collected from boring investigations. For this, 11 learning parameters (depth, rock type, RQD, electrical resistivity, UCS, V_p, V_s, Young's modulus, unit weight, Poisson's ratio, RMR) from 13 local tunnel cases were selected, 337 learning data sets as well as 60 test data sets were prepared, and 6 machine learning algorithms (DT, SVM, ANN, PCA & ANN, RF, XGBoost) were tested for various hyperparameters for each algorithm. The results show that the mean absolute errors in RMR value from five algorithms except Decision Tree were less than 8 and a Support Vector Machine model is the best model. The applicability of the model, established through this study, was confirmed and this prediction model can be applied for more reliable rock mass classification when additional various data is continuously cumulated.

• Journal of Practical Agriculture & Fisheries Research
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• v.18 no.1
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• pp.13-24
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• 2016

Sixty Hanwoo steers(15 months of age; 409±29.2 kg of BW) were used to evaluate the effects of dietary vitamins A and D restriction on carcass characteristics. Steers were allotted randomly to 1 of 4 treatments: Control(diet supplemented with vitamins A, D and E), -A (diet supplemented with vitamins D and E), -D(diet supplemented with vitamins A and E) and -AD(diet supplemented with vitamin E only). Steers were fed the experimental diet for a period of 8 months(until 23 months of age), and then supplemented with vitamins A and D at 0.05% of the diet(as fed-basis) from 24 to 26 months of age, and at 0.1% of the diet from 27 to 31 months of age(harvesting time). Dietary restriction of vitamins A and D did not affect DM intake, daily gain and feed conversion ratio. But the concentration of serum retinol was significantly(P<0.05) decreased by vitamin A restriction with the lowest concentration being seen at 23 months of age(345.0 ㎍/L and 326.7㎍/L for control and -D treatment versus 169.3 ㎍/L and 175.4 ㎍/L for -A and -AD treatments). The serum concentration of 25(OH)D₃ was also decreased significantly(P<0.05) by vitamin D restriction and the lowest concentration was seen at 18 months of age(53.7ng/ml and 61.8ng/ml for control and - A treatment versus 24.0 ng/ml and 24.5 ng/ml for -D and -AD treatments). After the restriction period of vitamins A and D, the concentrations of retinol and 25(OH)D₃ for - A, -D and -AD treatments were recovered at those of control. Dietary restriction of vitamins A and D did not affect carcass weight, backfat thickness, ribeye area, quality grade and yield grade. But marbling score was significantly increased by vitamin A restriction compared with control(6.73, 6.87 and 5.73 for -A, -AD and control, respectively). The results of the present study suggested that dietary vitamin A restriction could improve marbling score in Hanwoo steers.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.4
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• pp.723-729
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• 2004

To develop foods using dried persimmon, hot-water extracts of dried persimmons were added into strong wheat flour in the ratio of 10, 20, 30, and 40% and the quality characteristics of baked products were investigated. The proximate compositions of dried persimmons hot-water extracts were 70.37% of moisture, 1.72% of crude protein, 0.18% of crude lipids, 1.99% of crude ash and 4.37% of crude fiber, respectively. With increasing the addition of dried persimmons hot-water extracts, moisture content of the added breads was increased to 47.20% from 41.12% of non-added bread and water activity to 0.576 from 0.495. Water binding capacity of the added dried persimmons hot-water extracts rasied weight of the bread but decreased specific volume. In the hunter's color values the more dried persimmons hot-water extracts was added, the lower L vaules we, and the higher a and b values we. In the texture property, the addition of dried persimmons hot-water extracts increased hardness, gumminess and chewiness, while decreased adhesiveness and fracturability. Judging from texture, taste and overall acceptability of the product, recommended substitution level for hot-water extracts of dried persimmons in bread was 30% or less.