• Korean Journal of Poultry Science
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• v.39 no.2
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• pp.97-104
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• 2012

Newcastle disease virus (NDV) infects a variety of birds with a wide range of clinical signs from asymptomatic to severe. During a 10-month period in 2011, a total of 1,024 sera from wild birds including 42 species of birds in 8 orders were collected and the seroprevalence of NDV in wild birds was evaluated by hemagglutination inhibition (HI) test. Evidence of NDV infection was observed in 12.6% (129/1,024) of wild birds with a maximum prevalence reported in Mandarin duck (27.8%, 32/115) followed by Mallard duck (20.8%, 57/274), Spot-billed duck (11.9%, 36/303), Pintail (2.9%, 1/34), Black-tailed gull (2.9%, 1/34), White-fronted goose (1.8%, 1/56) and Common teal (1.4%, 1/69). None of the other 35 species of wild birds were antibody-positive for NDV. Mandarin duck, Mallard duck and Spot-billed duck showed high sero-prevalance of 12.2% to 42% during winter season (November to March). Our results indicate that Mandarin duck, Mallard duck and Spot-billed duck might be natural reservoirs for NDV in Korea and the prevalence of NDV infection in wild birds displayed a seasonal pattern with high prevalence of NDV in winter season (November to March).

• Journal of the Korean Society of Groundwater Environment
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• v.5 no.4
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• pp.177-191
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• 1998

For various kinds of waters including surface water, shallow groundwater (＜70 m deep) and deep groundwater (500∼810 m deep) from the Pungki area, an integrated study based on hydrochemical, multivariate statistical, thermodynamic, environmental isotopic (tritium, oxygen-hydrogen, carbon and sulfur), and mass-balance approaches was attempted to elucidate the hydrogeochemical and hydrologic characteristics of the groundwater system in the gneiss area. Shallow groundwaters are typified as the 'Ca-HCO$_3$'type with higher concentrations of Ca, Mg, SO$_4$and NO$_3$, whereas deep groundwaters are the 'Na-HCO$_3$'type with elevated concentrations of Na, Ba, Li, H$_2$S, F and Cl and are supersaturated with respect to calcite. The waters in the area are largely classified into two groups: 1) surface waters and most of shallow groundwaters, and 2) deep groundwaters and one sample of shallow groundwater. Seasonal compositional variations are recognized for the former. Multivariate statistical analysis indicates that three factors may explain about 86% of the compositional variations observed in deep groundwaters. These are: 1) plagioclase dissolution and calcite precipitation, 2) sulfate reduction, and 3) acid hydrolysis of hydroxyl-bearing minerals(mainly mica). By combining with results of thermodynamic calculation, four appropriate models of water/ rock interaction, each showing the dissolution of plagioclase, kaolinite and micas and the precipitation of calcite, illite, laumontite, chlorite and smectite, are proposed by mass balance modelling in order to explain the water quality of deep groundwaters. Oxygen-hydrogen isotope data indicate that deep groundwaters were originated from a local meteoric water recharged from distant, topograpically high mountainous region and underwent larger degrees of water/rock interaction during the regional deep circulation, whereas the shallow groundwaters were recharged from nearby, topograpically low region. Tritium data show that the recharge time was the pre-thermonuclear age for deep groundwaters (＜0.2 TU) but the post-thermonuclear age for shallow groundwaters (5.66∼7.79 TU). The $\delta$$\^$34/S values of dissolved sulfate indicate that high amounts of dissolved H$_2$S (up to 3.9 mg/1), a characteristic of deep groundwaters in this area, might be derived from the reduction of sulfate. The $\delta$$\^$13/C values of dissolved carbonates are controlled by not only the dissolution of carbonate minerals by dissolved soil CO$_2$(for shallow groundwaters) but also the reprecipitation of calcite (for deep groundwaters). An integrated model of the origin, flow and chemical evolution for the groundwaters in this area is proposed in this study.

• Applied Microscopy
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• v.31 no.1
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• pp.19-35
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• 2001

Outlines for plasma $estradiol-17\beta$, components, electrophoretic patterns, and ultrastructural changes were obtained in female rainbow trout (Oncorhynchus mykiss) during the seasonal reproductive cycles. Plasma $estradiol-17\beta$ under the natural conditions, exhibited distinct seasonal variation, peaking very late in vitellogenic season during September, decreasing gradually the halt of spawning in December, and ultimately falling during the early stages of seasonal ovarian recrudescence in February and March. This change in $estradiol-17\beta$ appeared to stimulate vitellogenin production as evidenced by increases in plasma calcium, phosphorus, glucose, albumin and total protein levels. The electrophoretic patterns of late maturing or spawning oocytes were stained more intensively than those of late perinucleolus oocytes (molecular weights of approximately 70,000 and 200,000). Two protein bands were found in the SDS-PAGE separation, coincident with the $estradiol-17\beta$ hormone peak. Gonadosomatic indices (GSI) significantly increased from October to January, and showed the highest peak in January, coinciding with the numerically abrupt increase of ripe ova in female. A positive correlation (r=0.701, p<0.01) was established between plasma $estradiol-17\beta$ levels and the gonadosomatic index during the prespawning. The highest level of hepatosomatic index (HSI) observed in December. During the breeding season (December), the gonadotropes were large and filled with GTH-containing inclusions such as granules and globules. The vitellogenic phase began as late perinurleolus oocytes became transformed into early maturing oocytes through the accumulation of yolk, and oocytes reached the late maturing stages as the ooplasm was completely packed with yolk. Marked ultrastructural changed in the granulosa cells during nuclear migration involve the dilation of the rough endoplasmic reticulum and the appearance of the rod-shaped mitochondria with tubular cristae. Microvilli (finger-like projections), from the zona radiata and from the oocyte grew, and made contact with each other in the pore canals of the zona radials during vitellogenesis, but were withdrawn as the zona radiata became more compact and devoid of pore canals during oocyte maturation. The zona radiata grew to a tripartite structure such as an outer thin homogeneous layer, and two inner thick helicoidal layers (zona radials interna and zona radiata externa). Under the normal conditions, the ovarian follicle influenced the histological development and periodical secretion of the hormones , sufficient for a oogenesis and gonadal steroid production.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.38 no.1
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• pp.92-102
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• 2020

The followings are the landscape preference aspects from the 816 landscapes(景, Kyung), which comprise the 78 modern Palkyungs, presented by the 78 local governments in Korea. First, the natural environment elements selected as Kyung(景), which are topographical landscapes, mostly consist of mountain elements such as mountains, terrace(臺), rocks and stones and water elements classified as rivers, oceans, and lakes. Natural elements also include old-growth and giant trees such as pines, ginkgos, Japanese cornels and fringe trees, tree-lined streets and forests, and plant elements such as azaleas, rhododendrons, lotuses, reeds, and silver grasses which provide seasonal landscapes. Second, more than half of Kyung, selected as human environment elements, are historical and cultural heritages such as graveyards, mountain fortresses, town fortresses, traditional villages, pavilion in villas, and temples. And it is followed by leisure tourism facilities such as traditional markets, exhibition halls, theme parks, beaches, and food streets, green-based structures such as trails, plazas, parks, and botanical gardens, and industrial heritages such as ranches, abandoned coal mines, stations, ports and bridges. Third, modern Palkyungs include objects not related to the views such as local representative facilities, regional products, and festivals. Fourth, although most of the modern Palkyungs consist of eight, some include 20, 38, or 100 in order to increase the number of objects of public relations. Fifth, a certain local government makes two modern Palkyungs with different subjects by introducing traditional Palkyung and modern Palkyung altogether. In this case, it presents several modern Palkyungs like by selecting Palkyungs in a limited area. Furthermore, one Palkyung includes numerous place names at a time in some cases. Sixth, Sosangjeonhyeong(瀟湘典型)-style modern Palkyung uses 'NakAn(落雁)' as the name of Kyung. Sosangyusahyeong(瀟湘類似型)-style modern Palkyung expresses 'Hyojong(曉鐘)' and landscape of glow of the setting sun, sunset, night view, dawn, sunrise and depicts cloud, sunset, moon, and snow. There are many Myeongsocheheomhyeong(名所體驗型)-style Palkyungs exhibiting the behavior of tourism and Myeongseunghyeong(名勝型)-style Palkyungs raising the awareness only by the names of the places. Seventh, modern Palkyung's naming styles are diverse, such as using only four letters instead of specifying Kyungmul(景物) or Kyungsaek(景色) in combination with Chinese characters or adding modifiers specializing in places.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.4
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• pp.307-319
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• 2000

Community structure (seasonal fluctuation), taxon diversity, nematodes/benthic harpacticoids and nematodes/kinorhynchs ratios of meiobenthos were studied in the Gamak Bay, Korea. A series of samplings were carried out from April 1997 to May 1999. Meiobenthic organisms was collected by van Veen grab and three subcores of 34 mm in internal diameter were taken from each sediment sample. The total density of meiobenthos in each seasons was found to be the highest in May 1999, and the lowest in December 1998. Total density of meiobenthos at each station was the highest at Station 9 in May 1999 ($2,218 inds./10 cm^2$) and the lowest at Station 3 in December 1998 ($2 inds./10 cm^2$). The Gamak Bay seemed to have an individual number increased from the inner toward the outer stations. The highest number of meiobenthos was observed on 0.125 and 0.063 mm mesh size. In every season, over $80{\%}$ of the meiobenthos was composed of only four groups: nematodes, benthic harpacticoids, sarcomastigophorans and nauplius larvae of crustaceans. Seasonal fluctuation of meiobenthos was also studied. The nematodes/benthic harpacticoids(nematodes/kinorhynchs) ratios were studied as an index of pollution monitoring for benthic ecosystem at each station in each season. The value of nematodes/benthic harpacticoids ratio was the highest at the inner stations and the lowest at the outer stations in the Gamak Bay. Taxon diversity (H') was the highest at the outer stations and the lowest at the inner stations in the Gamak Bay. The value of nematodes/benthic harpacticoids ratio significantly increased from the outer toward the inner stations, whereas the taxon diversity (H') significantly increased from the inner toward the outer stations in Gamak Bay.

• Journal of agricultural medicine and community health
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• v.29 no.2
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• pp.303-314
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• 2004

Objectives: This study was carried out to assess exposure levels of organic dusts and ammonia in poultry farms in Korea. Methods: A total of six poultry farms were investigated. The farms were located in Namwon, Chonlabuk-do and in Kae-San, Chungchongbuk-do. This study consisted of a questionnaire and measuring organic dusts and ammonia. The questionnaire included the characteristics of the farms, work patterns and the tasks of the poultry farms. Results and Conclusions: The farmers raised the chickens 45 times a year and the average number of years in the poultry farm were eight years ranging from 2 to 12 years. They worked for seven days per week and the average hours spent caring the chickens are 6.3 hours per day. The duration of staying in the confinement buildings was 3.3 hours per day. The work time in summer was longest. The feed and the water supply systems were automatic and the control of ventilation windows used "winch curtain" was semiautomatic. They used mechanical ventilation system in winter and used dilution ventilation system in the other seasons. The geometric mean concentration of total and respirable dust sampled in the poultry confinement buildings was 4.0 mg/$m^3$and 0.9 mg/$m^3$ respectively. The ratio of respirable to total dusts range from 9 to 49 percent. There was no sample exceeding the criteria 10 mg/$m^3$ for total dust and 3 mg/$m^3$ for respirable dust in farms. The criteria have been recommended by Korean Ministry of Labor and American Conference of Governmental Industrial Hygienist. The personal respirable dusts measured during a circle work averaged geometric mean concentration 1.4 mg/$m^3$ Two personal samples were exceeded the threshold 3 mg/$m^3$. There was a positive relation between an index and the personal samples of respirable dusts($R^2$=0.98). The index is calculated by multipling the total number of chickens in the farm by the age of the chickens and then dividing by the volume of the confinement building. The geometric mean concentration of area and personal ammonia samples was 23.3 ppm and 22.2 ppm, respectively. Some of the ammonia samples, both area and personal samples, exceeded the short term exposure limit value 35 ppm.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.1
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• pp.100-109
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• 2012

Removal rates of $PO_4-P$ and TP in a free water surface wetland system were investigated. The system was established in 2008 on a floodplain in the middle reach of the Gwangju Stream flowing through Gwangju City. Its dimensions were 46 meters in length and 5 meters in width. Two year old Typha angustifloria L. growing in pots were planted on half of the area and Zizania latifolia Turcz on the other half in 2008. Stream water was funneled into the wetlands by gravity flow, and its effluent was discharged back into the stream. The influent volume was controlled by valves and water depth was adjusted by wires. Volume and water quality of inflow and outflow were analyzed from January to December in 2010. Inflow into the system averaged approximately $710m^3/day$ and hydraulic residence time was about 1.5 hours. Average influent and effluent $PO_4-P$ concentration were 0.144 and 0.103mg/L, respectively, and $PO_4-P$ abatement amounted to 28.6%. Influent and effluent TP concentration averaged 0.333 and 0.262mg/L, respectively, and TP retention reached to 20.7%.$PO_4-P$ removal rate(%) during plant growing season(31.448) was significantly high(p<0.001) when compared with that during plant non-growing season(25.829). TP abatement rate(%) during plant growing season(27.230) was also significantly high(p<0.001) when compared with that of the non-growing season(14.856). Major phosphorous removals in the system resulted from adsorption of phosphorous in the litter-soil layers; sedimentation of particulate phosphorous and Ca, Al, Fe bounded phosphates; and absorption of phosphorous by emergent plants. The adsorption and sedimentation occurred throughout the year, however, the absorption took place during plant growing season. This resulted in higher removals of $PO_4-P$ and TP during plant growing season.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.2
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• pp.52-64
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• 2014

I the recent years, Seoul, Daejeon, Changwon, and Suncheon have started to strengthen P.R. efforts on eco-brands produced by the city and to publicize as a specialized tourist city in an attempt to change their identity and image. However, there is actually a question whether the efforts of the local governments have any direct impact on satisfaction with urban living environments and the attractions of the city. The purpose of this study was to examine the awareness of residents and visitors about the attractions of Suncheon City as an eco-city and to discuss the planning criteria for the eco-city brand building and its management. The research data was collected in Suncheon City and main results of this study are as follows. The residents and the visitors investigated were satisfied with the environmental friendliness of this city and regarded it as an eco-city. As a result of asking them why they viewed the city as an eco-city, many of the residents cited diverse green tracts of land as the reason, whereas the visitors replied they were satisfied with the state of marshy areas preserved by the city. The psychological factors related to the satisfaction of the eco-city by the residents were composed of four factors, 'cultural factor', 'urban infrastructure factor', 'ecological factor' and 'scenery factor'. The visitors were composed of five factors, 'cultural factor', 'urban infrastructure factor', 'ecological factor', 'scenery factor' and 'amenity factor'. Out of the factors, the cultural factor and the urban infrastructure factor were found to exert the largest influence on the overall satisfaction of the residents and the visitors. The ISA(Importance-Satisfaction Analysis) was made, the residents and the visitors gave top priority to 'diversity of natural attractions', 'pleasant season and weather', 'beautiful scenery', 'diversity of rare animals and plants', 'diversity of parks', 'green areas and streets', 'broad ecological area' and 'the preservation of marshy areas' among the attractions of the eco-city. They placed importance on the activation of green traffic and walking environments as well, but they weren't satisfied with the state of the two in the city. Therefore there was much room for improvement in that regard.

• Korean Journal of Microbiology
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• v.33 no.4
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• pp.262-266
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• 1997

Total, direct viable count, and acid-tolerant epiphytic bacterial population sizes were quantified on leaves of chestnut tree (Castanea crenata S. et Z.) near Taejon Industrial Estate affected by acid precipitation and deposition as well as in the clean natural forest area, Mt. Kyejok, in Taejon city from August 1996 to August 1997. Geometric mean numbers of total, direct viable count, and acid-tolerant epiphytic bacteria were $9.9{\times}10^5cell/cm^2$, $1.6{\times}10^6cell/cm^2$, and $7.1{\times}10^3cfu/cm^2$ respectively, being 1.5, 2, and 2.6 times those in the clean area. Acid-tolerant epiphytic bacterial numbers at pH 5.6 by MPN method were $3.3{\times}10^4$ in the industrial area, about the same as the number, $3.4{\times}10^4MPN/cm^2$, of the clean area. Acid-tolerant bacterial number at pH 4.0 was $1.9{\times}10^{-1}MPN/cm^2$ in the industrial area, whereas none was detected in the clean area. Acid-tolerant bacteria at pH 3.0 were not detected at all in the industrial area as well as in the clean area. Epiphytic bacterial population sizes were generally the greatest in May when leaves are emerged and grew hut the lowest in November when defoliation occurs. These results showed that air pollutant deposition on leaves did not cause a decrease of epiphytic bacteria at least and acid deposition on leaves did cause an increase of acid-tolerant bacteria.

• Journal of Korean Society of Forest Science
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• v.76 no.4
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• pp.397-409
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• 1987

This study was executed to analyze the user's impact on vegetation structure changes and user's psychology in Odongdo Island of Hallyo-Haesang National Park. Five sites were sampled for vegetation structure changes vi the study area according to the extent of impact observed. Also user's psychology was studied through questionnaire with the visitors and 366 answers were collected at random sampling in May, 1986. Evergreen broad-leaved forest, i.e. Machilus thunbergii, Cinnamomum camphora, and Camellia japonica forest, took possession of 32.5% (3.91ha) of total forest area when condisering the actual vegetation. Camellia japonica community covered 40.0% (4.72ha) and Sasa coreana community took possession of 41.8% (5.02ha). The area of environmental impact grade 3 and 4 area covered 44.3% of total forest area and it should be restored because self-repair seemed to be impossible. The evergreen broad-leaved forest was destoryed seriously with no younger trees in middle and lower layers by overuse impact and would be bared soon. So the preservation of autochthonous flora is required by the control of the number of users. It was shown that most of visitors come on holidays and Sunday and places which were favorably impressed were shown as the area of showing the sea and Camellia forest. Overall levels of satisfaction was comparatively low, consequently 55% of visitors were satisfied. This level of satisfaction was associated with number of users, landscape of forest and number of facilities.