• Journal of Preventive Medicine and Public Health
• /
• v.49 no.1
• /
• pp.45-52
• /
• 2016

Objectives: Previous large-scale cohort studies conducted in Korea have found a positive association between diabetes mellitus (DM) and colorectal cancer (CRC) in men only, in contrast to studies of other populations that have found significant associations in both men and women. Methods: A total of 1070 CRC cases and 2775 controls were recruited from the National Cancer Center, Korea between August 2010 and June 2013. Self-reported DM history and the duration of DM were compared between cases and controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by binary and polytomous logistic regression models. Results: DM was associated with an elevated risk of CRC in both men (OR, 1.47; 95% CI, 1.13 to 1.90) and women (OR, 1.92; 95% CI, 1.24 to 2.98). This association remained when we controlled for age, body mass index, alcohol consumption, and physical activity level. In sub-site analyses, DM was associated with distal colon cancer risk in both men (multivariate OR, 2.04; 95% CI, 1.39 to 3.00) and women (multivariate ORs, 1.99; 95% CI, 1.05 to 3.79), while DM was only associated with rectal cancer risk in women (multivariate OR, 2.05; 95% CI, 1.10 to 3.82). No significant association was found between DM and proximal colon cancer risk in either men (multivariate OR, 1.45; 95% CI, 0.88 to 2.41) or women (multivariate OR, 1.79; 95% CI, 0.78 to 4.08). Conclusions: Overall, DM was associated with an increased risk of CRC in Koreans. However, potential over-estimation of the ORs should be considered due to potential biases from the case-control design.

• Journal of Korean Society of Forest Science
• /
• v.85 no.3
• /
• pp.443-452
• /
• 1996

A study has been made to estimate biomass and NPP based on equation form of $Wt=aD^bH^c$ for Quercus variabilis and Quercus mongolica natural stands(Mean age; 67, 62yrs old) in Chungju. Equation form of $Wt=aD^bH^c$ was more adequate than $Wt=a(D^2H)^b$ and $Wt=aD^b$ for the estimation of the biomass and NPP. Individual biomass was compared using a paired t-test by tree component which showed no significant differences. Total aboveground biomass of Quercus mongolica was 130.6 t/ha and that of Quercus variabilis was 137.4 t/ha. Biomass of Q. mongolica was composed of foliage 5.1 t/ha(3.9%), dead branch 3.5 t/ha(2.7%), live branch 29.7 t/ha(23.0%), bolebark 16.2 t/ha(12.5%), and bolewood 74.9 t/ha(58.0%), and that of Q. variabilis was composed of foliage 3.8 t/ha(2.9%), dead branch 2.9 t/ha(2.2%), live branch 24.3 t/ha(18.4%), bolebark 20.4 t/ha(15.5%), and bolewood 80.4 t/ha(61.0%). Net primary production was 10.0 t/ha/yr in the Q. mongolica stand and 8.6 t/ha/yr in the Q. variabilis stand, respectively. Net primary production of Quercus forest in Chungju was very close to the mean NPP of the broadleaved forest of temperate zone.

• Journal of Environmental Health Sciences
• /
• v.42 no.4
• /
• pp.235-245
• /
• 2016

Objectives: This study estimated the adult Korean daily intake of acrylamide (AA) and investigated its relationship with demographic, lifestyle and dietary habits by using urinary concentrations of N-acetyl-S-(2-carbamoylethyl)-cysteine (AAMA). Methods: Human data (n=1870) was collected in a nationwide cross-sectional biomonitoring program representing the population (18-69 years) residing in South Korea. Urinary AAMA was analyzed with a LC-MS/MS system. Daily intakes of AA were estimated using mass daily AAMA, which was calculated through urinary AAMA concentration and daily creatinine excretion. Statistical analysis was performed with SAS procedures for calculating geometric means, confidence intervals and the exponentiated beta coefficient of multiple linear regressions. Results: Daily intake of AA was estimated at $0.475{\mu}g/kg$ body weight (BW) per day (95% confidence interval (CI): 0.447-0.503). In the case of current smokers, AA intake was $0.957{\mu}g/kg$ BW per day (95% CI: 0.847-1.067), which was significantly higher than that of former smokers and never smoked (p<0.0001). The strong affecting factors were age (95% CI: 0.68-1.14; p=0.0180), education level (95% CI: 1.05-1.42; p=0.0163), body mass index (BMI) (95% CI: 1.00-1.82; p<0.0001), and smoking status (95% CI: 0.97-3.05; p<0.0001). Korean dietary habits increasing AA intake were coffee (p=0.0005), cup noodles (p=0.0010) and canned foods (p=0.0005). Meanwhile, foods decreasing AA intake were fresh fruit (p=0.0076), cooked beef (p=0.0335) and cooked pork (p=0.0147). Conclusion: The Korean daily intake of AA in adults was estimated to be similar with those found in developed countries. The factors increasing daily AA intake were coffee, cup noodles and canned foods, and decreasing factors were fresh fruit, cooked beef and cooked pork.

• Magazine of the Korea Concrete Institute
• /
• v.6 no.6
• /
• pp.159-172
• /
• 1994

The relmund hammer test and ultrasonic pulse velocity test methods are commonly used to determine the in-situ compressive strength of concrete. One of the special feature of these methods is that they cannot give consistent and reliable results for variety of structures. In particular, very old existing structures have been generally received sreious environmental affectsand thus the strength prediction will be different from normal structures. The purpose of the present study is, therefore, to propose realistic equations to predict the in-situ strengths of actual old concrete structures. The rebound hammer and ultrasonic pulse velocity tests, carbonation depth measurments and core compressive strength measurements have been carried out for very old hydraulic and seacoast concrete structures spanning from one to about seventy years in age. From these test results, the strength-rebound number relations, the strength-pluse velocity relatinns and the strength-rebound number-pluse velocity relations have been obtained through multiple regression analysis. The present study indicates that the existing equations by nondestructive tests give quite different results from the present data. The proposed equations reasonably well predict the measured data for old concrete structures, especially for low strength concrete. The prediction equations proposed here can be efficiently used in determining the in-situ strength of old concrete structures.

• Journal of the Korea Concrete Institute
• /
• v.14 no.5
• /
• pp.782-788
• /
• 2002

Several non-destructive test methods have been developed to estimate compressive strength of concrete in other countries. However, their applications are limited in domestic concrete due to their inaccuracies. The purpose of this study is to propose an aging coefficient of compressive strength of structural concrete in rebound number method and ultrasonic pulse velocity method for domestic concrete. The test variables include type of aggregate, curing condition, and compressive strength. Two approaches are used to estimate aging coefficient. One is evaluated by uniform linear regression equation for all ages and shows uniform strength reduction coefficient regardless of material properties and the other is evaluated by individual regression equation for each ages and shows nonuniform strength reduction and rebound increasing coefficients which decrease with increasing of rebound number and compressive strength. The latter result which can include the effect of rebound number and compressive strength is more resonable than the former.

• Sleep Medicine and Psychophysiology
• /
• v.11 no.2
• /
• pp.100-105
• /
• 2004

Objectives: Major depression is associated with an increased risk of cardiovascular mortality. One possible explanation for this association is that major depression influences autonomic neurocardiac regulation. However, previous studies on the relationship between heart rate variability (HRV) and major depression have revealed conflicting results. The purpose of this study is to clarify that major depressive patients compared to healthy controls show a reduction in HRV as an expression of reduced modulation of vagal activity to the heart. Methods: According to DSM-IV, the time and frequency domain HRV indices (5-min resting study) of 30 patients with major depressive disorder were compared with those of 30 healthy controls. Standardized HRV tests enable quantitative estimation of autonomic nervous system function. Results: After controlling for age and gender, subjects with major depression showed a higher heart rate and significantly lower modulation of cardiovagal activity compared to controls. The total power (TP) band, very low frequency (VLF: 0.003-0.04 Hz) band, low frequency (LF: 0.04-0.15 Hz) band, and high frequency (HF: 0.15-0.4 Hz) band were significantly reduced in subjects with major depression compared to control subjects. Conclusion: Patients with major depression may suffer from functional disturbances in the interaction between the sympathetic and parasympathetic autonomic systems.

• Asian-Australasian Journal of Animal Sciences
• /
• v.23 no.4
• /
• pp.417-424
• /
• 2010

The purpose of this study was to detect significant SNPs for carcass quality traits using DNA chips of high SNP density in Hanwoo populations. Carcass data of two hundred and eighty nine steers sired by 30 Korean proven sires were collected from two regions; the Hanwoo Improvement Center of National Agricultural Cooperative Federation in Seosan, Chungnam province and the commercial farms in Gyeongbuk province. The steers in Seosan were born between spring and fall of 2006 and those in Gyeonbuk between falls of 2004 and 2005. The former steers were slaughtered at approximately 24 months, while the latter steers were fed six months longer before slaughter. Among the 55,074 SNPs in the Illumina bovine 50K chip, a total of 32,756 available SNPs were selected for whole genome association study. After adjusting for the effects of sire, region and slaughter age, phenotypes were regressed on each SNP using a simple linear regression model. For the significance threshold, 0.1% point-wise p value from F distribution was used for each SNP test. Among the significant SNPs for a trait, the best set of SNP markers were selected using a stepwise regression procedure, and inclusion and exclusion of each SNP out of the model was determined at the p<0.001 level. A total of 118 SNPs were detected; 15, 20, 22, 28, 20, and 13 SNPs for final weight before slaughter, carcass weight, backfat thickness, weight index, longissimus dorsi muscle area, and marbling score, respectively. Among the significant SNPs, the best set of 44 SNPs was determined by stepwise regression procedures with 7, 9, 6, 9, 7, and 6 SNPs for the respective traits. Each set of SNPs per trait explained 20-40% of phenotypic variance. The number of detected SNPs per trait was not great in whole genome association tests, suggesting additional phenotype and genotype data are required to get more power to detect the trait-related SNPs with high accuracy for estimation of the SNP effect. These SNP markers could be applied to commercial Hanwoo populations via marker-assisted selection to verify the SNP effects and to improve genetic potentials in successive generations of the Hanwoo populations.

• The Journal of Fisheries Business Administration
• /
• v.51 no.3
• /
• pp.1-15
• /
• 2020

The Korean government has been carrying out the marine ranch development project since 1998 with the purpose of responding to the decrease in coastal fishery resources and fishery income, preparing a systematic management system for the sustainable use of fishery resources and realizing advanced fisheries power by expanding and upgrading fisheries resource development projects. In addition, the government established the Korea Fisheries Resources Agency and promoted projects for the protection and management of fishery resources by increasing basic productivity by artificially creating marine forests in areas where whitening events occur. Since the project of building marine ranches and marine forests requires immense government financial support, it is important to estimate the economic value and thoroughly evaluate the feasibility of the project. In this paper, the project of non-market economic value of the development of marine ranches and the development of marine forests was estimated. CVM (Contingent Valuation Method) was applied as a methodology for benefits estimation. Prior to the analysis, a one-on-one interview survey was conducted with participation of 512 residents and 514 residents respectively for the project of creating a marine ranch and developing a marine forest. A DBDC (Double-Bounded Dichotumous Choice) model was applied in the WTP (Willingness To Pay) analysis model and the socioeconomic variables of the surveyor, such as sex, age, education and income, were reflected in the model. The economic benefits from the two projects, namely, building of marine ranches and developing marine forests were estimated to be equal to 4,608 won and 7,772 won per household per year, respectively. According to the results of the survey, it seems that respondents think that marine forests are more valuable than marine ranches. This is as a result of ordinary citizens' thought that the marine ranches are more cost-effective than the marine forests. The benefits estimated through this study can be used for analysis of economic feasibility prior to carrying out the project of building marine ranches and developing marine forests, and are considered to be the valuable for policy-making purposes and finding social and economic consensus.

• Journal of Korean Society of Forest Science
• /
• v.106 no.4
• /
• pp.457-464
• /
• 2017

This study has utilized the stand density management diagram to devise an efficient management standard for the stand density for Pinus densiflora that secures the health of the stands and predicted the harvest goals. The appropriate stand control level was estimated by modeling the relationship of the relative yield index (Ry) to the ratio of slender trees within the stand through an exponential function; the coefficient of determination ($R^2$) was found to be 0.424 according to the estimation. The ratio of slender trees within the stand showed a tendency of rapid increase at a certain relative yield index; with this relational function, the appropriate Ry value of 0.84 was obtained. By estimating the curve of the Ry value 0.84, which was the appropriate stand density management level, as well as the height of dominant trees in the central region of Korea, the production objective for each site index was set. Assuming that the final age by the site indices ranged from 10 to 16 for the P. densiflora in central region of Korea, the number of production was estimated to be between 426 to 1,311 trees per ha. It was predicted that the production of medium-diameter logs larger than 30 cm in diameter is possible for the target DBH at a site index of more than 16; small-diameter logs larger than 20 cm in diameter for site indices 12 and 14 enabled, and small-diameter logs of less than 20 cm for site index 10.

• Economic and Environmental Geology
• /
• v.3 no.2
• /
• pp.55-73
• /
• 1970

The district investigated covers the central and southern portions of the Uiryong Quadrangle amounting to $40km^2$ in area and is bounded approximately by geographical coordinates of $128^{\circ}$ 28' $40^{{\prime}{\prime}}{\sim}128^{\circ}$ 24' 25"E in longitude and $35^{\circ}10{\prime}{\sim}35^{\circ}14^{\prime}06^{{\prime}{\prime}}N$ in latitude. The purpose of this investigation was to provide basic information in drawing up a comprehensive development plan of the copper ore deposits known to exist in the HamanKumbuk district with special emphasis given to the ascertainment of geological and paragenetic characteristics. The area consists chiefly of shale, sandy shale and chert, all belong to Kyongsang System of Cretaceous age. Intruded into these rocks are andesite, granodiorite, basic dikes, and acidic dikes. The mineralization which took place in the area, consists of mostly fissure-filling vein deposits, numbering several tens, with varying magnitudes. The fissures and shear zones created in rocks, such as chert and granodiorite, hosted the deposition of mineralizing vapors and/or hydrothermal solutions along their openings. The strike lengths of these veins vary from 50 to 600 meters in extension and 0.1 to 3 meters in width. Although the degree of fluctuation in width is great, it averages 0.3m. The stuctural patterns, which apparently affected the deposition of veins, are fissure patterns, trend NS to $N30^{\circ}W$, and steep-pitching tension fractures as well as normal fault pattern. Ore minerals associated with vein matters are primarily chalcopyrite and small amounts of scheelite, cobaltiferous arsenopyrite, and gold and silver intimately associated with sulphide minerals. Associated with these ore mineral are pyrite, pyrrhotite, magnetite, specularite and arsenopyrite. Gangue minerals noted are quartz, calcite, chlorite, tourmaline and hornblende. In terms of the compositions of associated minerals, the vein deposits in the district could be grouped under the following four categories: 1. Pyrrhoitite, Arsenopyrite, Gold and Silver Bearing Copper Vein (Type I) 2. Calcite-Scheelite-Copper Vein (Type II) 3. Magnetite-Pyrite-Copper Vein (Type III) 4. Tourmaline Copper Vein (Type IV) Of the four types, the first and the fourth are presently yielding relatively higher grades: of copper ores and concentrates. The estimated ore reserves total some 222,000 metric tons with the following breakdown in terms of metal contents: Name of Mines Au(g/t) Ag(g/t) Cu(%) Reserves(M/T) Kunbuk 15.92 78.69 6,074 60.498 Cheil Kunbuk - - 1.040 60,847 Haman - - 2.688 101,204 222,549 As rehabilitation of old workings and/or exploration of veins at depth proceed, additional estimation of ore reserves may become apparent and necessary. With regard to the problem of beneficiation and upgrading of low-grade ores in the district, it would be advisable to make decisions on location, treating capacity and mill flowsheet after sufficient amount of exploration is completed as suggested in the report.