• Animal cells and systems
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• v.2 no.2
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• pp.259-267
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• 1998

A deletion of one out of the two copies of 9-bp repeat sequence (CCCCCTCTA), between the cytochrome oxidase II and Iysine tranfer RNA (COII/$tRNA^{Lys}$) genes in human mitochondrial DNA (mtDNA) has been used as a polymorphic anthropological marker for people of east Asian origin, and to lesser extent, Pacific and African populations. We searched for the 9-bp deletion of the intergenic COII/$tRNA^{Lys}$ Lys region in two Korean populations (175 from Seoul and 38 from Cheju) and examine the distibution of this deletion in world populations. The 9-bp deletion was detected directly by electrophoresis of the polymerase chain reaction (PCR)-amplified nucleotide(nt) 8211-8310 mtDNA fragment. The frequencies of the 9-bp deletion were significantly different between the Seoul (16%) and Cheju (8%) populations. Examination of data from the world populations suggests a geographic gradient. The frequency reaches its highest values in some Pacific island populations and decreases along the southeast Asia-Siberia transect. In spite of this geographic gradient, Mongoloid populations including Korean, Chinese, Japanese, and Mongolian populations were relatively homo-geneous with regard to the 9-bp deletion type of the intergenic COII/$tRNA^{Lys}$ region. These results indicate Koreans are genetically related to northeast Asian populations, and have a maternal mongoloid ancestry. Therefore, the 9-bp deletion of the intergenic COII/$tRNA^{Lys}$ region will provide significant information to elucidate the historical patterns of migration of the Mongoloids.

• The Korean Journal of Ecology
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• v.27 no.6 s.122
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• pp.363-367
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• 2004

Photosynthetically active radiation (PAR) beneath the forest canopy, understory species richness and diversity, and biomass were measured in a Larix leptolepis plantation seven years after thinning in Yangpyeong. Four different thinning intensities (control, $10\%,\;20\%\;and\;40\%$ stocking reduction) were applied in 1997. The current PAR values were lower than those measured four years after thinning, and PAR at the heavy thinning plots was significantly higher than that of other thinning intensities. A total of 23 species including 9 tall-trees and 14 shrubs were found for the high layer while a total of 82 species including 10 tall-trees, 29 shrubs, and 43 herbs for the low layer. Species richness and diversity generally increased with thinning intensities, and the trends were more evident for the low layer. Aboveground biomass significantly differed among thinning intensities for both shrubs and herbs. Also there was a negative correlation between biomass and the current number of stems per hectare. The current study suggested that the effects of thinning on light conditions at the forest floor, species richness and diversity and production of understory vegetation continued seven years after the treatment.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• no.1
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• pp.43-52
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• 2001

One of the major environmental issues Japanese cities is now facing with is the conservation of seminatural landscapes for the restoration of ecological integrity of urban areas. The satoyama landscape, which includes coppice woodlands, agricultural areas and rural settlements, is seen as an indispensable semi-natural landscape, formed as a result of man-nature interaction. However, because of the loss of the economic viability they are now abandoned and in the process of losing their ecological values. Today a number of local municipalities as well as NPO groups are involved in the conservation projects of these landscapes. Although satoyama landscapes are commonly believed to have maintained their character over the years, historical studies have revealed that these landscapes have experienced constant and dynamic changes due to a variation in human impacts. It is therefore understood that the conservation projects on satoyama landscapes should not intend to restore their past condition, but should wet the goal of maintaining their dynamic character by promoting ecological roles which the landscapes may play in the contemporary world. EXPO2005 project in Aichi Prefecture is a good example of a development project underway on satoyama landscapes which intend to conserve the landscapes by stimulating contemporary ecological for them. In EXPO2005 project the key issue was the conservation of semi-natural landscapes formed by constant and intensive human impacts over the centuries and thus allowing endemic and endangered species to be accommodated. The planning team proposed a scheme to restore economic viability of satoyama landscapes. The scheme involves re-introducing intensive human impacts through a new management system with an innovative technology. This may restore the economic viability of lumbers provided form satoyama woodlands. EXPO2005 is understood as a model case which stimulates contemporary ecological functions of satoyama landscapes by applying innovative planning concepts.

• Journal of Biosystems Engineering
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• v.25 no.5
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• pp.369-378
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• 2000

The purpose of this study is to developed high-efficient rotary tillage system for a power tiller by improving the rotary blade. A kind of the rotary blade with single-edged blade(DS) was developed that requires lower tillage energy than conventional double-edged blade(CD) on the design theory for Japanese rotary blade. In order to find out the tillage characteristics between the single-edged blade and the double-edged blade for power tiller, experiments were performed in soil-bins which were filled up clay loam, loam and sandy loam, and then analyzed the effects of the factors such as soil texture, travelling speed, rotational speed, and tillage depth to each of the blades. And field tests were carried out to compare tillage performances of the two blades using rotary cultivator driven by conventional power tiller. The results of this study were summarized as follows; 1) On the soil bin experiment, it was found that tillage torque of the single-edged blade was less than the ones of the double-edged blade. The decreasing ratios of maximum tillage torque of the single-edged blade to the ones of the double-edged blade were 1 to 8% at clay loam, 5 to 20% at loam and 9 to 31% at sandy loam, respectively. 2) By the field tests, that the tillage performances with the single-edged blade compared with the double-edged blade was improved about 19% in field capacity, about 34% in fuel consumption, and 12.5% in soil breaking ratio. Furthermore, the fluctuation of engine speed, the variation of exhaust gas temperature, and the amount of soil clogging on the blade and straw wound on the rotary shaft showed lower values with the developed blade than the conventional blade. So, it may be concluded that tillage performance by the developed single-edged blade was improved compared with the one by the conventional double-edged blade.

• Journal of Veterinary Clinics
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• v.20 no.4
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• pp.496-500
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• 2003

A one-year-old male Japanese Chin with anorexia, retching, dyspnea and continuous coughing was brought to the Veterinary Teaching Hospital, Chungbuk National University. Chest radiographs showed moderate regional alveolar pattern with mild interstitial patterns in the caudo-dorsal lung fields and the ill-defined mass in the perihilar area which is consistent with perihilar lymphadenopathy. Although the dog showed severe eosinophilia in the complete blood count, the serum profile values were within normal ranges. There was no indication of any parasite infestation in the direct and floatation examination of feces, skin scraping test and heartworm examination. There was no growth of bacteria and fungi in the selected media such as Mueller Hinton broth, Sabouraud Dextrose agar and Potato Dextorse agar, which were inoculated with tracheal fluid collected using endotracheal tube and cultured for 3 days. In the tracheal fluid smear, most prominent cells were eosinophils, which are a almost 80% of total cells and other cells such as leukocytes, neutrophils and ciliated colummar cells were also observed. Any parasite was also not detected in its smear. Prednisolone (PDS; 1 mg/kg, BID SC), aminophylline (10 mg/kg, TID IV) and nebulization with gentamicin (50 mg) plus saline (3 ml) were given for 1 week. At 3rd day of treatment, blood eosinophil value was return to normal range and pulmonary condition was also improved. The allergen test with serum performed during therapy was positive in the 19 index including milk, barley, tomato pomace, catfish, bonito, house dust and wool, and borderline in 10 index including wheat, house dust mites and house fly. The patient is responding well to PDS therapy. Based on these findings, a possible diagnosis of pulmonary infiltration with eosinophils was made in this dog.

• Journal of Preventive Medicine and Public Health
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• v.33 no.4
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• pp.477-483
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• 2000

Objectives : To obtain reference values for the pulmonary asbestos and non-asbestos fiber contents of residents in Korea and to compare them with similar results from Japan. Methods : The autopsied lung specimens from 22 deceased people (20 males and 2 females) in Pohang, without any known occupational history of asbestos exposure, were analyzed for incidence of asbestos and non-asbestos fibers by transmission electron microscopy with energy dispersive X-ray analysis after using low temperature ashing procedures. Results : Chrysotite fiber (46.2%) was the major fiber type found in the lungs of the subjects. The asbestos fiber concentrations found in males and females were $0.09\times10^6$ fiberss(g of dry lungs) and $0.30\times10^6$ fibers/(g of dry lungs), respectively, showing a geometric mean concentration $0.09\times10^6$ fibers/(g of dry lung tissue), due to the predominance of males in the sample. The non-asbestos fiber contents in males and females were $4.61\times10^6$ fibers/(g of dry lungs) and $17.79\times10^6$ fibers/(g of dry lungs), respectively, with a geometric mean concentration $5.21\times10^6$ fibers/(g of dry lung tissue). Conclusions : Residents in Pohang had significantly lower levels of both asbestos and non-asbestos fibers than urban residents in Korea. Furthermore, Koreans had significantly lower levels of both asbestos and non-asbestos fibers than Japanese.

• Economic and Environmental Geology
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• v.18 no.2
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• pp.151-157
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• 1985

Events detected by the KIER microearthquake network operated in the Southern Part of Korea for 265 days in 1982~1984 were reviewed, and some of them were identified to be a dynamite explosion from several construction sites. The purpose of the present work is to determine the crustal structure of the Southern Korea using the time-destance data obtained from such explosion seismic records. The time·distance data can be well explained by a crustal model composed of four horizontal layers of which thickness, p and s-wave velocity ($V_p$ and $V_s$) are characterized as follows. 1st layer (surface) ; 0~2km, $V_p=5.5km/sec$, $V_s=3.3km/sec$ 2nd layer (upper crust) ; 2~15km, $V_p=6.0km/sec$, $V_s=3.5km/sec$ 3rd layer (lower crust) ; 15~29km, $V_p=6.6km/sec$, $V_s=3.7km/sec$ 4th layer (upper mantle) ; 29km~ , $V_p=7.7km/sec$, $V_s=4.3km/sec$ The relatively shallow crust·mantle boundary and low $P_n$ velocity compared with the mean values for stable intraplate region are noteworthy. Supposedely, it is responsible for the high heat flow in the South-eastern Korea or an anomalous subterranean mantle. The mean $V_p/V_s$ ratio calculated from the relation between p-wave arrival and s-p arrival times appears to be 1.735 which is nearly equivalent to the elastic medium of ${\lambda}={\mu}$. However, the ratio tends to be slightly larger with the depth. The ratio is rather high compared with that of the adjacent Japanese Island, and the fact suggests that the underlying crust and upper mantle in this region are more ductile and hence the earthquake occurrences are apt to be interrupted. As an alternative curstal model, a seismic velocity structure in which velocities are successively increased with the depth is also proposed by the inversion of the time·distance data. With the velocity profile, it is possible to calculate a travel time table which is appropriate to determine the earthquake parameters for the local events.

• Steel and Composite Structures
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• v.33 no.4
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• pp.615-627
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• 2019

This paper aims to study the compressive behavior of circular hollow and concrete-filled steel tubular stub columns under simulated marine atmospheric corrosion. The specimens after salt spray corrosion were tested under axial compressive load. Steel grade and corrosion level were mainly considered in the study. The mechanical behavior of circular CFST specimens is compared with that of the corresponding hollow ones. Design methods for circular hollow and concrete-filled steel tubular stub columns are modified to consider the effect of marine atmospheric corrosion. The results show that linear fitting curves could be used to present the relationship between corrosion rate and the mechanical properties of steel after simulated marine atmospheric corrosion. The ultimate strength of hollow steel tubular and CFST columns decrease with the increase of corrosion rate while the ultimate displacement of those are hardly affected by corrosion rate. Increasing corrosion rate would change the failure of CFST stub column from ductile failure to brittle failure. Corrosion rate would decrease the ductility indexes of CFST columns, rather than those of hollow steel tubular columns. The confinement factor ${\xi}$ of CFST columns decreases with the increase of corrosion rate while the ratio between test value and nominal value shows an opposite trend. With considering marine atmospheric corrosion, the predicted axial strength of hollow steel tubular and CFST columns by Chinese standard agree well with the tested values while the predictions by Japanese standard seem conservative.

• Journal of Creative Information Culture
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• v.6 no.2
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• pp.57-64
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• 2020

As the information society gradually advances, various opinions overflow and their complexity increases. As the results, it was made more difficult to derive important issues and properly respond to those problems. Accordingly, it is necessary to get a handle on emerging problems in education in addition to existing discourses and issues. This study aimed at examining the issues of education by analyzing the petitions posted under 'parenting and education' category on National Petition board. In order to offer objective and detailed results, we employed the topic modeling based LDA algorithm, which is an effective method to extract topics in multiple documents. Nine topics were derived as the result of the analysis and the relationship among those topics was visualized. The values of this study exist in that the derived topics represent important issues that reflect the public opinions.

• Journal of Radiation Protection and Research
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• v.47 no.3
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• pp.143-151
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• 2022

Background: After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, biological alterations in the natural biota, including morphological changes of fir trees in forests surrounding the power plant, have been reported. Focusing on the terminal buds involved in the morphological formation of fir trees, this study developed a method for estimating the absorbed radiation dose rate using radionuclide distribution measurements from tree organs. Materials and Methods: A phantom composed of three-dimensional (3D) tree organs was constructed for the three upper whorls of the fir tree. A terminal bud was evaluated using Monte Carlo simulations for the absorbed dose rate of radionuclides in the tree organs of the whorls. Evaluation of the absorbed dose targeted ¹³¹I, ¹³⁴Cs, and ¹³⁷Cs, the main radionuclides subsequent to the FDNPP accident. The dose contribution from each tree organ was calculated separately using dose coefficients (DC), which express the ratio between the average activity concentration of a radionuclide in each tree organ and the dose rate at the terminal bud. Results and Discussion: The dose estimation indicated that the radionuclides in the terminal bud and bud scale contributed to the absorbed dose rate mainly by beta rays, whereas those in 1-year-old trunk/branches and leaves were contributed by gamma rays. However, the dose contribution from radionuclides in the lower trunk/branches and leaves was negligible. Conclusion: The fir tree model provides organ-specific DC values, which are satisfactory for the practical calculation of the absorbed dose rate of radiation from inside the tree. These calculations are based on the measurement of radionuclide concentrations in tree organs on the 1-year-old leader shoots of fir trees. With the addition of direct gamma ray measurements of the absorbed dose rate from the tree environment, the total absorbed dose rate was estimated in the terminal bud of fir trees in contaminated forests.