• Journal of Korean Society of Forest Science
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• v.105 no.1
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• pp.63-72
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• 2016

A study was conducted to evaluate the effect of collected region(Bongpyeong in Gangwon, 690 m, Mt. Halla in Jeju, 1,085 m), pre-treatment (stratification, soaked in distilled water or $GA_3$) and shading (control, 50%, 80%) on seed emergence and seedlings growth of Ligularia fischeri. The result showed that seed emergence (%) of L. fischeri were 6.9~75.5% (Gangwon : 6.9~32.8%, Halla : 22.2~75.5%). Maximum seed emergence (%) of 32.8 (Gangwon) and 75.5 (Halla) were achieved for seeds were stratified, soaked in distilled water, and under non-shading for L. fischeri (Gangwon), whereas seeds were stratified, soaked in $GA_3$ 100 ppm, and under 80% shading for L. fischeri (Halla). In this study, the best seedling vigor index (SVI) of L. fischeri (Gangwon) and L. fischeri (Halla) were obtained when seeds were stratified, soaked in distilled water, and under 50% shading. The survival rate of potted seedlings for L. fischeri (Halla) were 100% of all shading conditions, but there were decreased by 77.8%, 61.1%, 55.6%, as an increasing shading rate (con, 50%, 80%) for L. fischeri (Gangwon). Therefore, good seedlings were obtained when seed (Mt. Halla) of L. fischeri were stratified, soaked in distilled water, and under 50% shading, and then seedlings were transferred in pot.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.2
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• pp.103-111
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• 2013

In this study, field measurements were conducted in the section about 7 km from sea dike to westward. The observations of along channel current were carried out, and water temperature and salinity were measured simultaneously at 10 stations during one tidal cycle, and sampling interval is 1 hour. The maximum ebb current is about 1.5 m/s at the surface layer but flood current is 0.4 m/s at the bottom layer during discharge period. Residual current during river discharge shows two layer structures which is typical characteristic of the estuary system. On the other hand, residual current during a period with no discharge has shown multi-layer structure different from general estuarine systems. The distribution of high salinity can be seen at the bottom layer as the effect of discharge does not reach down to the bottom layer during discharge. As a result, freshwater is not effected at the bottom layer during observation, and mixing of surface layer to bottom layer is reduced by stratification.

• Journal of Preventive Medicine and Public Health
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• v.32 no.4
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• pp.505-512
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• 1999

Objectives : The purpose of this study was to assess the relationship between job strains and absenteeism from work. Methods : The study design was cross-sectional, and the study subjects consisted of 1,166 workers who were employed in the small-sized industries. A self administered questionnaire was used to measure the general characteristics, job characteristics(job demand, job control), and social support(coworker support, supervisor support) at work. The Job Content Questionnaire(JCQ) was used to assess job demand(2 items) and decision lattitude(10 items). Social support at work (10 items) was measured using JCQ. Sick absence was collected using self-report and were rechecked by the attendance record of their company. Odds ratios and 95% confidence intervals for the association between job strain and sick absence were estimated. The modifying effect of social support was evaluated by stratification. Logistic regression was used to estimate the relationship between job strain and sick absence. Results : In the bivariate analysis, the variables related to sick absence were age, marital status, occupation, job demand. Four distinctly different kinds of level of job strain were generated by the combination of job demand and job control: low strain group, high strain group, active group, and passive group. The crude odds ratio of high job strain was 1.78(95% CI: 1.26-2.53), and those of active group and passive group were 1.33(95% CI: 1.07-1.66) and 1.13 (95% CI: 0.88-1.47), respectively. The odds ratio of high job strain after adjusting for age and occupation were still significant The odds ratio of high job strain in low social support was 5.96(95% CI: 2.45-14.51), but that in high social support was 0.73(95% CI: 0.26-2.01). Conclusions : Job strain was associated with increased risk of absenteeism from work, and social support at work modified the association between job strain and sick absence.

• Journal of Environmental Science International
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• v.23 no.5
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• pp.771-780
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• 2014

Tetragonia tetragonides is a medicinal plant native to ocean sand soil of southern provinces and has significant effects on the prevention and curing of gastroenteric disorders. Despite of its popularity, supply of the plant has never met the level of demand because of the absence of an adequate culturing method. The present study, thereby, was conducted for classifying the plants with geographically different characteristics, studying growth habits, developing a new culturing method and establishing a large scale propagation system of selected superior individual plants. The study was also aimed for revealing optimum conditions for seed treatment, fertilization, and efficient culturing system and thereby, for utilizing the plant as a new income source for rural communities. The seed was elongated with size of 2.6 mm (width) ${\times}$ 1.8 mm (length). No difference in seed size was observed depending on different inhabitate. Each flower produced about 4.5~4.8 seeds. Germination rate was high for seeds matured for 40 days after fertilization, but deceased to 50% for seeds matured only for 20 or 30 days. Seed dormancy lasted 6 months and seed storage at humid $5^{\circ}C$ facilitated germination. Mechanical obstruct of seed germination was due to seed coat and removal of seed coat enhanced the germination rate. Optimum temp. for seed storage was $5^{\circ}C$, and high germination rate was maintained for 350 days. However, for stratification condition or at room temperature, germination was significantly reduced as storage time increased Optimum treatment of plant growth regulators was soaking in $GA_3$ 250 mg/L for 1 hr. The priming treatment with 50 mM $Ca(NO_3)_2$ at $20^{\circ}C$ for two days improved the seed germination with 10% compared to non-treated control. The treatment of 20% NaOCl for 3 hr. improved the seed germination rate up to 10% and 1 day ahead.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.3
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• pp.323-329
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• 1998

The data of Secchi disc observation collected during $1966\~1990$ were analyzed to investigate the seasonal variation of transparency in the southeastern Yellow Sea. The bimonthly distribution of mean transparency showed that the isolines of transparency were roughly parallel to the isobaths. The transparency was low (3 m in february and 8 m in August) if the shallow water less than 20 m depth in comparition to the higher values (10 m in february and 17 m in August) in the deeper water. The lowest transparency was found in winter. The transparency increased in spring and the highest transparency occurred in summer. The water becomes turbid in autumn. Suspended solid concentrations in winter are ranged from 28 to 130 $mg/{\ell}$, and from 8 to 60 $mg/{\ell}$ in summer. The seasonal variation of transparency seems to be mainly affected by resuspension of solid from the bottom. The amounts of suspended solid are large in winter due to the vertical convection by cooling effect and tubulence by the strong wind, and small in summer due to the strong stratification and weak wind.

• Journal of the Korean Electrochemical Society
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• v.2 no.2
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• pp.98-105
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• 1999

In the present study, buoyant force and its stabilizing effects in an electrostatic field were examined systematically in order to reduce the effect of natural convection with thermal stratification in a horizontal fluid-saturated porous layer. The correlation of ionic mass transport induced by double-diffusive convection in a horizontal porous layer has been derived theoretically. And the theoretical model was examined by electrochemical experiments. The theoretical correlation for mass transport which is satisfying Forchheimer's flow equation and based on the micro-turbulence model is derived as a function of soltual Darcy-Rayleigh number, thermal Darcy-Rayleigh number and Lewis number. In the experiment, the mass transport of copper ions in $CuSO_4-H_2SO_4$ solution is measured by electrochemical technique. By assembling theoretical correlation and experimental results, the mass transport correlation induced by double-diffusive convection is proposed as $$Sh=\frac{0.03054(Rs_D-LeRa_D)^{1/2}}{1-3.8788(Rs_D-LeRa_D)^{-1/10}}$$ The present correlation looks flirty reasonable with comparing experimental results, and very promising for the applications of its prototype into various systems involving heat transfer as well as mass transfer, in order to control the effects of natural convection effectively.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7169-7174
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• 2014

Background: NPAS2 is a product of the circadian clock gene. It acts as a putative tumor suppressor by playing an important role in DNA damage responses, cell cycle control and apoptosis. Chronic lymphocytic leukemia (CLL) appears to be an apoptosis related disorder and alteration in the NPAS2 gene might therefore be directly involved in the etiology of CLL. Here, the Ala394Thr polymorphism (rs2305160:G>A) in the NPAS2 gene was genotyped and melatonin concentrations were measured in a total of seventy-four individuals, including thirty-seven CLL cases and an equal number of age- and sex-matched healthy controls in order to examine the effect of NPAS2 polymorphism and melatonin concentrations on CLL risk in a Pakistani population. Materials and Methods: Genotyping of rs2305160:G>A polymorphism at NPAS2 locus was carried out by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). Melatonin concentrations were determined by enzyme linked immunosorbent assay (ELISA). Statistical analysis was performed using Statistical Package for Social Sciences software. Results: Our results demonstrated no association of the variant Thr genotypes (Ala/Thr and Thr/Thr) with risk of CLL. Similarly, no association of rs2305160 with CLL was observed in either females or males after stratification of study population on a gender basis. Moreover, when the subjects with CLL were further stratified into shift-workers and non-shift-workers, no association of rs2305160 with CLL was seen in either case. However, significantly low serum melatonin levels were observed in CLL patients as compared to healthy subjects (p<0.05). Also, lower melatonin levels were seen in shift-workers as compared to non-shift-workers (p<0.05). There was no significant difference (p>0.05) in the melatonin levels across NPAS2 genotypes in all subjects, subjects with CLL who were either shift workers or non-shift-workers. General Linear Model (GLM) univariate analysis revealed no significant association (p>0.05) of the rs2305160 polymorphism of the NPAS2 gene with melatonin levels in any of the groups. Conclusions: While low melatonin levels and shift-work can be considered as one of the risk factors for CLL, the NPAS2 rs2305160 polymorphism does not appear to have any association with risk of CLL in our Pakistani population.

• Korean Journal of Social Welfare
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• v.65 no.3
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• pp.29-52
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• 2013

This study examined how middle-aged and elderly persons allocated their time in overall perspective and whether the patterns were varied by age, socio-demographic factors, and the interaction effect between them. This study analyzed the 2009 Time Use Survey Data (17,096 time-diaries of people aged 45 or more) of the National Statistical Office using tobit regression model. The main results are as follows. First, middle-aged and elderly people gradually decreased paid work times. Second, the patterns of time allocation were varied by age, gender, education level, marital status and household type(Agricultural/non-agricultural). Third, there were interaction effects between age and the socio-demographic factors on paid work time and leisure time. Highly educated or urban persons were likely to have less time in paid work less than other groups with increasing age. And females were likely to have less time in domestic labor and care work than males with increasing age. But they had more time in social and economic productive activities than males. Based on these findings, this study suggests comprehensive approach to analyze the time use of elderly beyond economic working time or leisure time. To establish effective ageing society policy, it is necessary to consider the time allocation of elderly which divided into the social stratification.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.14
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• pp.5907-5912
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• 2015

Purpose: To evaluate and update evidence for prognostic effects of kidney-sparing (KS) management and nephroureterectomy (NU) for upper tract urothelial carcinomas. Materials and Methods: Pubmed, Embase and the Cochrane Library were retrieved for the identification of comparative studies of kidney-sparing procedure and nephroureterectomy for upper tract urothelial carcinoma prior to December 2014. The data were extracted independently by 2 reviewers and the quality of the included studies was assessed. Review Manager 5.3 and STATA 13 were used to perform the meta-analysis. Results: Twenty-three observational studies including 1,587 KS and 3,996 NU were evaluated. The results of the meta-analysis showed that nephroureterectomy had no significant benefit with regard to intravesical recurrence (IRFS), metastasis (MFS), cancer specific survival (CSS) and overall survival (OS) except the total tumor recurrence (RFS) when compared with kidney sparing management. The respectively pooled outcomes were HR 1.36 (0.69-2.68, P=0.38) for IRFS, 1.09 (0.59-2.01, P=0.78) for MFS, 1.17 (0.77-1.79, P=0.47) for CSS, 1.50 (0.90-2.48, P=0.12) for OS and 1.61 (1.03-2.51, P=0.04) for RFS. Conclusions: On the whole, kidney-sparing management had equivalent prognostic effect on upper tract urothelial carcinoma as the standard nephroureterectomy except in tumor recurrence. However, the results should be interpreted with caution for lack of stage and grade stratification and multi-center randomized controlled trials are still needed to verify our results.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.3
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• pp.230-237
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• 2000

An ecological study of the benthic macrofauna was carried out using a modified van Veen grab in September 1997, in Namdaechon estuary, Yangyang, Korea. A total of 17 macro-invertebrates was collected and examined from eleven stations in the study area, including 3,795 individuals and 738.63 g wet weight. Arthropods, annelids and molluscs were most abundant and occupied more than $95{\%}$ of the total number of species, individuals and biomass. Namdaechon estuary in Yangyang was very poor in macrobenthic biodiversity, and numerically dominated and characterized by the polychaetes Heteromastus filiformis, Hediste japonica, Eteone longa, an unidentified oligochaete Oligochaeta sp., a corbulid bivalve Corbicula japonica, and an estuarine isopod Cyathura higoensis. Species composition, species dominance, density, and species evenness were compared among stations. The macrofaunal azoic zone appeared in the bottom of 7 m in depth nearby the artificial bank to catch the salmons to return to the livers for spawning. It probably resulted from the oxygen depletion following strong stratification in summer, which can cause major effect on the ecological conditions and then finally kill bottom macro-invertebrates in this area. Moreover, some opportunistic species thrived in nearby another station and this is of vital importance in terms of the ecological succession in a benthic polluted area.