• Journal of Korean Society for Atmospheric Environment
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• v.28 no.2
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• pp.172-181
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• 2012

Mercury is one of the most hazardous air pollutants. Recently, mercury has been a concern in domestic and overseas because it has lethal toxicity, long distance transport, persistence and bioaccumulation in the environment. Stationary combustion sources such as coal-fired power plants, waste incinerators, and cement kilns are the major sources of mercury emissions. The objectives of this study were to measure the concentration for mercury from coal-fired power plants and to calculate emission factor to estimate its emission. The results showed that the mercury concentrations in the flue gas were 1.63-3.03 mg/$Sm^3$ in anthracite-fired power plants (average 2.32 mg/$Sm^3$) and 1.95-3.33 mg/$Sm^3$ in bituminous-fired power plants (average 2.6 mg/$Sm^3$). Mercury emission factor was estimated as 25.74 mg/ton for anthracite-fired power plants and 12.48 mg/ton for bituminous-fired power plants. Because actual measurements are limited in quantity, it is desirable to refine our estimates by extending the actual measurements.

• Korean Journal of Veterinary Research
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• v.51 no.1
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• pp.21-28
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• 2011

Salmonella Enteritidis (SE) has been a major causative agent of food-borne human disease due to consumption of contaminated eggs and poultry meat. To prevent SE infection in poultry, and therefore minimize human infections, vaccination with either killed or live SE vaccine is suggested. We evaluated a newly developed killed bacterin using a representative SE isolate in Korea. Among pool of SE isolates, two highly virulent isolates (the one isolate from chicken, the other from human) were selected by measuring mortality in mouse and chickens administered. The chickens were injected intramuscularly with killed vaccine and were challenged with highly virulent SE strain 3 week after vaccination. The recovered colony count (cfu/g) of spleen and cecal content in the vaccinated groups was reduced compared with those of the unvaccinated control group. The antibody level in the vaccinated groups was higher at 3 week post vaccination. These results indicate that vaccination with killed vaccine was effective in preventing the infection of virulent SE. Further study for a large number of layers should be needed for the effect of egg production, SE shedding in feces, persistence of antibody level.

• Journal of Ecology and Environment
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• v.35 no.2
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• pp.111-122
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• 2012

The sex ratio and spatial structure of different sexes are major components that affect the reproductive success and population persistence of dioecious plants. The differential reproductive costs between male and female plants are often believed to cause a biased sex ratio and spatial segregation of the sexes through slower growth and/or lower female survivorship. In this study, we examined the sex ratio and spatial structure of one population of $Torreya$ $nucifera$ trees in Jeju Island, Korea. We also tested the effects of the current tending actions in relation to tree vitality. At the population level, the sex ratio of the 2,861 trees was significantly biased toward males; however, it also showed considerable variation among different diameter at breast height classes and across habitats according to terrain level (from upper to lower). In 1999, before tree management (tending) began, among the ecological traits examined, only climber coverage correlated with tree vitality. Intensive tending such as climber removal since 1999 clearly enhanced the vitality of the majority of trees, but its effects were more conspicuous in medium-sized trees than in small ones, in upper terrain trees than those in other terrains, and in females than in males. Both male tree domination in small and large trees and tending effects on females are likely to reflect the effects of female reproductive costs regarding growth and/or survivorship. Spatial segregation between males and females was not observed in $T.$ $nucifera$. Habitat heterogeneity created by the forest's rocky ground and its implications regarding sex ratios and spatial structure require further studies.

• Journal of Korea Soil Environment Society
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• v.1 no.1
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• pp.19-27
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• 1996

Nonaqueous phase liquids(NAPL) not readily dissolved in water exist as a separate fluid phase. Groundwater contamination by NAPL such as organic solvents and petroleum hydrocarbons becomes major public concerns because of their long-term persistence in the subsurFace and their ability to contaminate large volumes of wate. Dense.-than-water NAPL(DNAPL) spilled into the subsurface penetrate through the saturated zone and ultimately form DNAPL pools on the bottom of the aquifer. The dissolution of DNAPL from these pools depends on the molecular diffusion coefficient, the vertical dispersivity, the groundwater velocity, the solubility, and the pool length. In this study, the vertical transverse dispersion coefficients for simulating the dissolution of DNAPL from such pools were obtained from the dissolution experiment. Under the experimental conditions used, the vertical transverse dispersion coefficients calculated were 1.86$cm^2$/day, 2.90$cm^2$/day and 4.51$cm^2$/4ay for seepage velocities of 59.2cm/day, 94.3cm/day and 158.0cm/day, respectively. And the vertical transverse dispersivity was 0.03024cm.

• Journal of Labour Economics
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• v.27 no.2
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• pp.29-66
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• 2004

In this paper, I investigate job creation and destruction in Korean mining and manufacturing between 1982 and 2000 using the raw data of Annual Mining and Manufacturing Survey. The rate of job creation and destruction of continuing plants averaged 9.75 and 10.33, respectively, which are higher than those of OECD countries, Chile, and Colombia. The created jobs showed weak persistence and the concentration of job reallocation is high, compared with other countries. Job reallocation accounts for major fraction of worker reallocation and the fraction has increased before 1997. Analysis of time series data of job flow revealed a general pattern of pro-cyclic job creation and counter-cyclic job destruction. However job reallocation in Korea is strongly acyclic whereas the rate is known to be counter-cyclical in the U.S.

• Journal of Korean Medicine for Obesity Research
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• v.4 no.1
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• pp.139-160
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• 2004

The obesity is detrimental to the health of people living in affluent societies. Individual differences in energy metabolism are caused primarily by single nucleotide polymorphisms(SNPs), some of which promote the development of obesity-related type 2 diabetes mellitus. Type 2 diabetes mellitus is a common multifactorial genetic syndrome, which is determined by several different genes and environmental factors. In this review, five major conclusions are reached: (1)To be clinically significant, SNPs must be relevant, prevalent, modifiable, and measurable. (2)Differences in SNPs may have been caused by famine, ultraviolet light, alcohol, climate, agricultural revolution. livestock, lactase persistence, and westernized lifestyle. (3)Candidate obesity genes of calorie intake restriction are SIM 1, MC3R, MC4R, AGRP, CART, CCK, CNTFR, DRD2, Ghrelin, 5-HT receptor, NPY, PON and those of energy metabolism are LEP, LEPR, UCP1, UCP2, UCP3, B2AR, B3AR, PGC-1, Androgen receptor and those of fat mobilization are AGT, ACE, ADA, APM1, Apolipoproteins, PPAR, FABP, FOXC2, GCGR, $11-{\beta}HSDI$, LDLR, Hormonal sensitive lipase, Perilipin, $TNF-{\alpha}$, $TNF-{\beta}$ (4)Candidate obesity genes in the eastern are NPY, LEP, LEPR, UCP1, UCP2, UCP3, B2AR, B3AR, ACE, APM1, PPAR, and FABP. (5)Candidate obesity genes in type 2 diabetes mellitus are MC3R, MC4R, B2AR, B3AR, ADA, APM1, PPAR, FABP, FOXC2, PC1, PC2, ABCC8, CAPN10, CYP19, CYP7, ENPP1, GCK, GYS1, IGF, IL-6, Insulin receptor, IRS, and LPL. The discovery of SNPs will lead to a greater understanding of the pathogenesis of obesity and to better diagnostics, treatment, and eventually prevention.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.8
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• pp.579-585
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• 2013

Persistent Organic Pollutants (POPs) are chemical substances which persist in the environment, bioaccumulate through the food web, and pose a risk of causing adverse effects to human health and the environment. POPs are thermally stable, highly lipophilic and water-insoluble compounds which can induce various toxic influences including immunotoxicty, carcinogenicity adverse effects on reproduction, development and endocrine fuctions. Polybrominated diphenyl ethers or PBDEs, are organobromine compounds that are used as flame retardant. Because of their toxicity and persistence, the industrial production of some PBDEs is restricted under the Stockholm Convention, a treaty to control and phase out major POPs. In this study, PBDEs was measured in various site of Sihwa industrial complex to investigate concentration distribution of POPs. The levels of PBDEs in house dust samples were 0.722~44.024 ng/g-dry. In PBDEs congener, BDE-209 was relatively higher in the all sites. The concentration of BDE-209 measured over 80.0% of total PBDEs. In various site, high molecular PBDEs homologues are measured higher than low molecular.

• Journal of Acupuncture Research
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• v.18 no.2
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• pp.237-244
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• 2001

Back pain has plagued humans for many thousands of years. The treatment of back pain is divided into operative treatment and conservative treatment. It is reported that cure rate of conservative treatment is 80~90 percent. Generally, the treatment of oriental medicine is mostly conservative treatment. But, surgery should not be used as a last resort in treatment; it is just one of many treatment options for various spinal conditions. In some instance, it can be to preferred choice; in other situations, alternative therapies may be superior. Selections of the operation in HIVD 1. Acute disc herniations with a protracted significant component af back pain. 2. Chronic disc degeneration with significant back pain and degeneration limited to one or two disc levels. 3. Sugical instability created during decompression. 4. The presence of neural arch defects coincident with disc disease. 5. Symptamatic and radiographically demonstrable segmental instability. Selections of the operation in stenosis 1. If it does not slowly progress in physical therapy and other nonoperative measures, many of these patients may ultimately need surgical decompression. 2. Absolute stenosis in an impression of CT, MRI.(under 10mm) 3. In patients with established symptoms of .neurogenic claudication. 4. In patients with bad influence of neurogenic derangement.(strength, sensory) Selections of the operation in spondylolisthesis 1. Persistence or recurrence of major symptoms for at least one year despite activity modification and physical therapy. 2. Tight hamstrings, persistently abnormal gait, or postural deformities unrelieved by physical therapy. 3. Sciatic scoliosis. 4. Progressive neurologic deficit. 5. Progressive slipping beyond 25 or 50 percent, even when asymptomatic. 6. A high slip angle (40 to 50 degrees) in a growing child, since it is likely to be associated with further progression and deformity. 7. Psychologic problems attributed to shortness of trunk, abnormal gait, and postural deformities characteristic of more severe slips.

• Journal of The Korean Association of Information Education
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• v.13 no.1
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• pp.9-22
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• 2009

As information technology(IT) has been rapidly developed, e-learning is also growing to meet the need of lifelong education using internet. However, with the growth of e-learning has come the big problem of high dropout rates. The purpose of this present study was to identify the major factors influencing drop-out in corporate e-learning. 250 employees(persistence: n=157, dropout: n=93) who enrolled an e-learning course in S company were participated in this study. A logistic regression analysis was performed to identify predictors of dropout. It was determined that individual background(marriage, amount of study time, difficult to combine work and family), learners' characteristics and value of the course were able to predict dropout with nearly 75 percent accuracy.

• Applied Biological Chemistry
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• v.38 no.3
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• pp.263-268
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• 1995

A study was undertaken to compare degradation patterns of carbofuran in soils between submerged and upland moisture conditions [$3-^{14}C$]Carbofuran was treated in each soils at the rate of 1.0 mg/kg (87.8 kBq $^{14}C/50g$ soil) and the time-course analysis for distribution of radioactivity and degradation products were conducted. Differences in the pathway and rate of carbofuran degradation in soils were observed between submerged and upland moisture conditiona major degradation being hydrolysis at 7-C position and oxidation at 3-C position, respectively. Carbofuran showed less persistence in soils of higher moisture contents A significant portion, $24{\sim}39%$ of the total radioactivity, resided in soils as nonextractable residues at 60 days after treatment The nonextractable radioactivity was mainly located in soil organic matter, fulvic acid, humic acid and humin factions Gel filtration chromatography confirmed the incorporation of carbofuran and its degradation products into the organic matter.