• Korean Journal of Poultry Science
• /
• v.41 no.2
• /
• pp.99-104
• /
• 2014

The objective of this study is to analyze the production of extra-large egg and assess the impacts of exogenous factors in feeding the layer chicken. The main results of this study are as follows; First, feeding rations on the basics of statistics, internal maximum and minimum temperature and, the age at first egg affect the production of extra-large egg. Second, implicating the standardized coefficients from the conclusion of regression model estimating suggest that the amount of feed has the greatest impact on production followed by the age at first egg. Third, by using the elasticity of output and the volatility in the production, the result suggest that among the independent variable factors in the external volatility, the biggest one goes to feed ration, and the age at first egg follows. In order to control the production volatility in the extra-large egg production of the farms, it is necessary to manage an efficient feeding based on feed ration, age at first egg and, the maximum and minimum temperature inside the farm. Taken together, the results demonstrates that it should be concentrated by controlling the exogenous factors affecting extra large egg production and the management system construct, to increase extra-large egg production and the income of farmers at the same time.

• Journal of Navigation and Port Research
• /
• v.26 no.1
• /
• pp.106-111
• /
• 2002

The estimation of pile bearing capacity is important since the design details are determined from the result. There are numerous ways of determining the pile design load, but only few of them are chosen in the actual design. According to the recent investigation in Korea, the formulas proposed by Meyerhof based on the SPT N values are most frequently chosen in the design stage. In the study, various static and dynamic formulas have been used in predicting the allowable bearing capacity of a pile. Further, the reliability of these formulas has been verified by comparing the perdicted values with the static and dynamic load test measurements. Also, in most cases, these methods of pile bearing capacity determination do not take the time effect consideration, the actual allowable load as determined from pile load test indicates severe deviation from the design value. The principle results of this study are summarized as follows : As a result of estimate the reliability in criterion of the Davisson method, t was showed that Terzaghi & Peck >Chin>Meyerhof > Modified Meyerhof method was the most reliable method for the prediction of bearing capacity. Comparisons of the various pile-driving formulas showed that Modified Engineering News was the most reliable method. However, a significant error happened between dynamic bearing capacity equation was judged that uncertainty of hammer efficiency, characteristics of variable, time effect etc... was not considered. As a result of considering time effect increased skin friction capacity higher than end bearing capacity. It was found out that it would be possible to increase the skin friction capacity 1.99 times higher than a driving. As a result of considering 7 day's time effect, it was obtained that Engineering news, Modified Engineering News, Hiley, Danish, Gates, CAPWAP(CAse Pile Wave Analysis Program) analysis for relation, repectively, $Q_{u(Restrike)} / Q_{u(EOID)} = 0.98t_{0.1}$ , $0.98t_{0.1}$, $1.17t_{0.1}$, $0.88t_{0.1}$, $0.89t_{0.1}$, $0.97t_{0.1}$.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.3 no.2
• /
• pp.59-70
• /
• 1998

Two-dimensional trend-vector model of sediment transport is first tested in the tidal flat of Garolim Bay, mid-western coast of the Korean Peninsula. Three major parameters of surface sediment, i.e., mean grain size, sorting and skewness, are used for defining the best-fitting transport trend-vector on the sand ridge and muddy sand flat. These trend vectors are compared with the real transport directions determined from morphology, field observation and bedforms. The 15 possible cases of trend vectors are calculated from total sediments. In order to find the role of coarse sediments, trend vectors from sediments coarser than < 4.5 ${\phi}$, (sand size) are separately calculated from those of total sediments. As compared with the real directions, the best-fitting transport-vector model is the "case M" of coarse sediments which is the combined trend vectors of two cases: (1) finer, better sorted and more negatively skewed and (2) coarser, better sorted and more positively skewed. This indicates sand-size grains are formed by simpler hydrodynamic processes than total sediments. Transported sediment grains are better sorted than the source sediment grains. This indicates that consistent hydrodynamic energy can make sediment grains better sorted, regardless of complicated mechanisms of sediment transport. Consequently, both transported vector model and real transported direction show that the source of sediments are located outside of bay (offshore Yellow Sea) and in the baymouth. These source sediments are transported through the East Main Tidal Channel adjacent the baymouth. Some are transported from the subtidal zone to the upper tidal flat, but others are transported farther to the south, reaching the south tidal channel in the study area. Also, coarse sediment grains on the sand ridge are originally from the baymouth, and transported through the subtidal zone to the south tidal channel. These coarse sediments are moved to the northeast, but could not pass the small north tidal channel. It is interpreted that the great amount of coarse sediments is returned back to the outside of the bay (Yellow Sea) again through the baymouth during the ebb tide. The distribution of muddy sand in the northeastern part of study area may result from the mixing of two sediment transport mechanisms, i.e., suspension and bedload processes. The landward movement of sand ridge and the formation of the north tidal channel are formed either by the supply of coarse sediments originating from the baymouth and outside of the bay (subaqueous sand ridges including Jang-An-Tae) or by the recent relative sea-level rise.

• Journal of Life Science
• /
• v.17 no.4 s.84
• /
• pp.510-514
• /
• 2007

This study was carried on cool and RT(room temperature) storage of unhulled rice. In RT storage of an analysis of coefficient relation, high significant positive coefficients were observed in toyo index and breakdown, setback and protein content. high significant negative coefficients were showed setback and breakdown, breakdown and protein content. In cool storage of an analysis of coefficient relation, high significant positive coefficients were observed in toyo index and amylose content and gelatinization start temperature and protein content and high significant negative coefficients were showed toyo index and whiteness, toyo index and gelatinization start temperature, gelatinization start temperature and amylose content. In RT storage of a path coefficient analysis, a highest positive direct influence was observed in amylose content and a highest negative direct influence was protein content. Positive indirect influence was high revealed breakdown and protein content and negative indirect influence was gelatinization start temperature and Mg/K ratio. In cool storage of a path coefficient analysis, a highest positive direct influence was whiteness and a highest positive indirect influence was gelatinization start temperature. Positive indirect influence was high revealed gelatinization start temperature and amylose content, negative indirect influence was whiteness and gelatinization start temperature. In RT storage of Multiple regression equation of Toyo index based on physicochemical properties of unhulled rice, a highest coefficient of determination was revealed among five facters of whiteness, protein content, Mg/K ratio, amylose content and gelatinization start temperature. In cool storage of Multiple regression equation of toyo index based on physicochemical properties of unhulled rice, highest coefficient of determination was revealed among five facters of moisture content, amylose content, gelatinization start temperature, breakdown and setback.

• Journal of Nutrition and Health
• /
• v.41 no.8
• /
• pp.754-766
• /
• 2008

This study was performed to evaluate the effect of nutrient intake levels on the relative risk of breast cancer in the Daegu and Gyeongbuk area. The case subjects were 103 patients newly diagnosed as breast cancer at Kyungpook National University Hospital. The control subjects were 159 healthy women without breast cancer-related disease in the same community selected by frequency matching of age and menopausal status. The survey was administered by individual interviews by trained dietitians using semiquantitative food frequency questionnaires. The odds ratios were determined by using unconditional logistic regression after adjusting for the confounding factors found in the analysis of general characteristics of the subjects. In overall, it has been found that high consumptions of energy and carbohydrates significantly raised the relative risk of breast cancer, and that high intakes of total fat, plant fat, dietary fiber, all kinds of fatty acids, vitamin E and calcium significantly lowered the risk of breast cancer. The results of the study suggest that the possible protective factors to the breast cancer risk include a higher intakes of total fat, especially plant fat, dietary fiber, and micronutrients such as vitamin E, folic acid, calcium, phosphorus and potassium. On the other hand, high intakes of energy and carbohydrate appeared to be the risk factors.

• Journal of Nutrition and Health
• /
• v.50 no.2
• /
• pp.142-157
• /
• 2017

Purpose: The purpose of this study was to develop a nutrition quotient for adolescents (NQ-A) to assess overall dietary quality and food behavior of Korean adolescents. Methods: Development of the NQ-A was undertaken in three steps: item generation, item reduction, and validation. Candidate items of the NQ-A checklist were selected based on literature reviews, results of the fifth Korea National Health and Nutrition Examination Survey data, dietary guidelines for Korean adolescents, expert in-depth interviews, and national nutrition policies and recommendations. A total of 213 middle and high school students participated in a one-day dietary record survey and responded to 41 items in the food behavior checklist. Pearson's correlation coefficients between the responses to the checklist items along with nutritional status of the adolescents were calculated. Item reduction was performed, and 24 items were selected for the nation-wide survey. A total of 1,547 adolescents from 17 cities completed the checklist questionnaire. Exploratory factor and confirmatory factor analyses were performed to develop a final NQ-A model. Results: Nineteen items were finalized as the checklist items for the NQ-A. Checklist items were composed of five factors (balance, diversity, moderation, environment, and practice). The five-factor structure accounted for 47.2% of the total variance. Standardized path coefficients were used as weights of the items. The NQ-A and five-factor scores were calculated based on the obtained weights of the questionnaire items. Conclusion: Nutrition Quotient for adolescents (NQ-A) would be a useful instrument for evaluating dietary quality and food behavior of Korean adolescents. Further research on NQ-A is needed to reflect changes in adolescent's food behavior and environment.

• Tuberculosis and Respiratory Diseases
• /
• v.55 no.6
• /
• pp.560-569
• /
• 2003

Background : A large number of pollutants such as sulfur dioxide, nitric oxide, carbon monoxide, particulate matter, and ozone influence on the body. These pollutants put a burden on the lung and the sequelae resulting from the oxidative stress are thought to contribute to the development of fibrotic lung disease, emphysema, chronic bronchitis and lung cancer. Also, carbon monoxide generated from the incomplete combustion of carbon-containing compounds is an important component of air pollution caused by traffic exhaust fumes and has the toxic effect of tissue hypoxia and produce various systemic and neurologic complications. The objective of this study is to compare the difference of pulmonary function and serum carboxyhemoglobin(CO-Hb) level between the traffic policemen and clerk policemen. Method : Three hundred and twenty-nine of traffic policemen, and one hundred and thirty clerk policemen were included between 2001 May and 2002 August. The policemen who took part in this study were asked to fill out a questionnaire which included questions on age, smoking, drinking, years of working, work-related symptoms and past medical history. The serum CO-Hb level was measured by using carboxyoximeter. Pulmonary function test was done by using automated spirometer. Additional tests, such as elecrocardiogram, urinalysis, chest radiography, blood chemistry, and CBC, were also done. Results : $FEV_1(%)$ was $97.1{\pm}0.85%$, and $105.7{\pm}1.21%$(p<0.05). FVC(%) was $94.6{\pm}0.67%$, and $102.1{\pm}1.09%$, respectively(p<0.05). Serum CO-Hb level was $2.4{\pm}0.06%$, and $1.8{\pm}0.08%$(p<0.05). After correction of confounding factors (age, smoking), significant variables were FVC(%), $FEV_1(%)$ and serum CO-Hb level(%)(p<0.05). Conclusion : Long exposure to air pollution may influence the pulmonary function and serum CO-Hb level. But, further prospective cohort study will be needed to elucidate detailed influences of specific pollutants on pulmonary function and serum carboxyhemoglobin level.

• KDI Journal of Economic Policy
• /
• v.31 no.1
• /
• pp.105-138
• /
• 2009

Although the decline in fertility rate is generally observed along the history of economic development throughout the world, the continuing decline hitting below the replacement level in Korea over the recent years gathered serious social concerns on the ground that it accelerates the process of population aging. The total fertility rate in Koreareached 2.08 in 1983, and gradually fell to the levels of 1.08 in 2005 and 1.26 in 2007. The policy debate over the role of the government has been focused mainly on the level of theoretical discussion without substantial basis on firm empirical evidence and the determinants of fertility. The objective of the paper is to empirically investigate the fertility effect of the female wage, which is understood as one of the most important determinants of fertility in Koreasince 1980 focusing on one aspect of fertility, namely birth spacing. Using the Korean National Fertility Survey conducted in 2006, I estimate a duration model of first and second births taking into account individual heterogeneity, which turned out to be an important factor to control for. Compared with previous studies in the literature on the Korean fertility, the study has an advantage of using the complete pregnancy history of women in a more representative sample. Unlike the previous studies, the analysis also deals with the endogeneity of marriage by treating a certain age, rather than age at marriage, as the time in which a woman becomes exposed to the risk of pregnancy. The study shares the common problem in the literature on birth spacing of lacking relevant wage information for respondents in a retrospective survey. I estimate the wage series as a function of the basic characteristics using the annual Wage Structure Survey from 1980 to 2005, which is considered as a nationally representative sample for wage information of employees. The results suggest that the increase in female wage by 10 percent leads to a decrease in second birth hazard by 0.56~0.92 percentage points and that the increase in spouse's wage by the equal amount is accompanied by the increase in second birth hazard by 0.36~1.13 percentage points. These estimates are more precisely estimated and of smaller magnitude than those presented by the previous studies. The results are robust to the different specifications of the wage equation. The simulation analysis based on the predicted values shows that about 17% of the change in the second birth hazard over the period 1980 to 2005 was due to the change in the female wage. Although there is some limitation in data, the results can be viewed as one estimate of the role of female wage on the recent fertility decline in Korea. The question raised by the paper is not a normative one of whether a government should promote childbearing but a positive one thatexplains fertility decline. Therefore, if there is a wide consensus on promoting childbearing, the finding suggests that the policies designed to reduce the opportunity cost of women in the labor market would be effective. The recent movement of implementing a wide range of family-friendly policies including child care support, maternity leave, parental leave and tax benefit in developed countries should be understood in this context.

• Korean Journal of Psychosomatic Medicine
• /
• v.8 no.1
• /
• pp.46-57
• /
• 2000

Objectives : The purpose of the present study was to examine the effect of subacute treatment with the selective serotonin reuptake inhibitors(paroxetine and sertraline) on immobility in the forced swim test(FST) and on FST-induced changes in immune parameters of the mice. Methods : Authors applied a modified method of FST by Porsolt et al. Over 5 BALB/c mice were used for each group of experiments. To explore the changes in immune parameters by FST, authors investigated the production of anti-rat RBC antibody, concanavalin A(ConA)- or lipopolysaccharide(LPS)-stimulated splenocytes proliferation assay and cytokine gene expression. Results : Both paroxetine and sertraline decreased the duration of immobility in a dose-related manner. FST-performed mice showed a significant decrease in mitogenic responses of splenocytes and a slight increasing tendency in anti-rat RBC antibody response. All these responses were attenuated significantly by paroxetine and attenuated nearly nominal significance level by sertraline. The cytokine profiles of ConA-stimulated splenocytes from FST-performed mice showed stronger expression of IL-4 and weaker expression of IL-2 than control mice, and no changes in the expressions of IFN-$\gamma$ and lymphotoxin. IL-6 and IL-10 were not expressed in both group of mice. The pretreatment of paroxetine and sertraline attenuated the altered cytokine expressions in FST-performed mice to some extent. Some alterations of the expressions of IL-6 and IL-10 were observed in the mice which the selective serotonin reuptake inhibitors had been pretreated. Conclusion : The subacute treatment of paroxetine and sertraline attenuated the FST-induced behavioral and immune changes, and these serotonin reuptake inhibitors may exert some modulating effects on the immune system by the induction of cytokine gene expression, especially IL-6 and IL-10.

• Journal of dental hygiene science
• /
• v.13 no.4
• /
• pp.471-479
• /
• 2013

This study is trying to grasp the stress of the male high school students and the correlation between the stress according to the academic and economic level and oral parafunctional habits, emphasizing the need for the education of oral parafunctional habits, providing the basic data in order to accomplish correctly until the oral health of the oral maxillofacial region. From May 2013 till July 2013, a self administered survey was conducted by the selected by convenience sampling from subjects of 1, 2 grade of two high school located in Chungnam, Korea. The study results were as follow: 1) Among five areas of stress, the stress of school life was the highest as 2.11 points and the stress of home problem was the lowest as 1.51 points; 2) the stress by class showed that grade 2 was higher than grade 1 in all areas. The stress of the school life (2.21) (p<0.01), interpersonal relationship (p<0.01), and own problem (p<0.05) showed the significant difference; 3) The significance analysis results between the five areas of stress according to the stress of latent variable and the oral parafunctional habits all showed the significant difference (p<0.001). The correlation between the stress and the oral parafunctional habits showed a weak negative correlation as -0.30, and the stress of the school life, own problem, environment problem, and interpersonal relationship showed very strong correlations more than 0.7; 4) Fit measures test result of stress, academic level, and family economic level model all showed more than 0.9 in good of fit index, adjusted goodness of fit index, normed fit index and root mean square residual and root mean square error of approximation values is all estimated less than 0.1, so it showed good model. From this study, it can be concluded that there is the correlation between stress and oral parafunctional habits.