• Korean Journal of Environment and Ecology
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• v.26 no.5
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• pp.707-718
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• 2012

This study was conducted to monitor 4 years of changes in the vegetation structure starting from 2007 when restoration began and propose vegetation management ideas for the riparian ecological restoration areas in the purchased land around Nakdonggang(River). The study was conducted in each of 15 locations ($208,342m^2$) in the riparian ecological restoration areas in November 2007, September 2008, October 2009 and September 2010. The analysis results of the changes in planting species and population showed that, in the case of trees, Acer pseudo-sieboldianum, Quercus acutissima, Acer ginnala, Quercus aliena, Quercus variabilis indicated relatively little changes in their numbers and Quercus dentata, Cornus walteri, Morus alba, Styrax obassia, Sorbus alnifolia var. macrophylla indicated a 100% withering rate. Most shrubs withered due to the oppressive pressure of herbs and climbing plants. The planting density decreased over 4 years on average 28 plants/$100m^2$ to 20 plants/$100m^2$ to 16 plants/$100m^2$. Shortly after the restoration, The the amount of growth was reduced by restoration stress. however as time goes on after the restoration tended to stabilize. The changes in the basal area showed a decrease from $507.1cm^2/100m^2$ in 2007 right after restoration to $301.8cm^2/100m^2$ in 2008 and afterwards showed an increasing trend by going to $324.9cm^2/100m^2$ in 2009 and $372.7cm^2/100m^2$ in 2010. To improve the planting structure of the riparian ecological restoration area, the selection of tree species that have been considered for soil moisture and the differentiation of suitable planting structures that have been considered for local conditions were needed.

• Journal of dental hygiene science
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• v.9 no.3
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• pp.295-302
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• 2009

The purpose of this study is to provide fundamental data for managing occupational stress and promoting health by investigating the factors of dental hygienists' occupational stress and the relationship among occupational stress, health status and somatization. The subjects in this study are 28 dental hygienists who have worked at dental clinic in the metropolitan area. The findings of this study are as follows: 1. The average age of the subjects is 25.1 and the average working career is 42.8 months. 8-9 hours is the most frequent average working time as 55.5% and a 6-day workweek appears most frequently with 33.8%. 2. The total average of occupational stress is 45.24 points and out of the seven sub-factors, job demand is the highest as 56.17 points. 3. A group of working at dental university hospitals scores significantly high and a group of working over 10 hours per day scores significantly low in health status (p<0.05). 4. A group of a 5-day workweek. night and holiday duty scores 18.64 which is significantly high in somatization(p<0.05). 5. Occupational stress have slightly negative correlation (-.341, p<0.01) with health status and slightly positive correlation (.330, p<0.01) with somatization. There is a strong, negative correlation between health status and somatization(-.762, p<0.01 ). 6. Health status and somatization have a slightly positive correlation with every other sub-factor of occupational stress except job self-control.

• Korean Journal of Environment and Ecology
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• v.34 no.5
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• pp.396-401
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• 2020

As the world becomes more globalized, the non-native species issue has emerged as a problem that is growing internationally. In particular, the number of non-native turtles found in the wild has been increasing sharply in South Korea. At least 15 species of non-native turtles, including the red-eared slider (Trachemys scripta elegans) first imported in the 1970s, have been found in Korea. On October 15, 2019, an alligator snapping turtle (AST, Macrochelys temminckii) was found in a stream located in Gwangju city, South Korea. The discovery of AST became a big issue in South Korea as the animal is known for its large body size and aggressiveness and was featured widely in the mass media. In this study, to learn the public's perception of non-native species, we examined comments (opinions) to the online news articles about the AST. We collected 1,100 comments from the Internet news articles on the AST. Out of the 1,100 comments, 342 (31.1%) comments were related to non-native species' issues. Most of the respondents (97.7%, n=334) stated that the non-native species are a problem. Forty two comments mentioned potential threats posed by non-native species: non-native species' aggressive nature (n=11, 26.2%) and ecological disturbance (n=31, 73.8%). Lack of responsibility (n=122, 51.7%) was the major causative factor for the introduction of non-native species, and followed by indiscriminate pet trade (n=99, 42.0%), absence of relevant legislation (n=13, 5.5%), and absence of treatment (n=2, 0.8%). Animal registration (n=59, 45.7%) was the most commonly mentioned as the way to deal with the issue of the non-native species' invasion. Our results show that the public is aware of the seriousness of the invasion of non-native species, including AST. This study highlights that researchers and government officials need to consider the public's perception and opinions. We believe that our study can serve as an essential reference for the policy direction and the management of non-native species.

• Korean Journal of Environmental Agriculture
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• v.36 no.3
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• pp.161-168
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• 2017

BACKGROUND: Rabbiteye blueberry(Vaccinium ashei Reade) has low nutrient uptake efficiency due to its shallow and fibrous root system without root hairs. This study was carried out to establish an efficient nutrient application standard by investigating the effect of nitrogen fertigation on the growth and fruit characteristics of rabbiteye blueberry. METHODS AND RESULTS: 'Brightwell' rabbiteye blueberry was treated with 0, 50, 100 and 200% nitrogen fertigation of recommended fertilizer application (6, 9 and 14 g/bush in the first, second and third years, respectively). The results showed that leaf nitrogen content significantly correlated with the fruit weight and fruit yield. However, canopy area, dry weight, sugar and anthocyanin contents did not correlate significantly with the leaf nitrogen content. The leaf and stem dry weights of 'Brightwell' rabbiteye blueberry during the third year of planting were the highest with 50% nitrogen fertigation (leaf dry weight=723.7 g/bush; stem dry weight=890.7 g/bush). Maximum fruit yield of 'Brightwell' rabbiteye blueberry (12.9 kg/bush) was observed during the third year of planting with 50% nitrogen fertigation and this was about 70% greater than the treatment that received no nitrogen fertigation. The fruit yields of 'Brightwell' rabbiteye blueberry during the third year of planting treated with 100 and 200% nitrogen fertigation were 11.0 and 11.5 kg/bush, and these were 17 and 12%lower than the 50% nitrogen fertigation treatment, respectively. Further, the efficiency of nitrogen utilization was the highest (90%) with 50% nitrogen fertigation and lowest (18%) with 200% nitrogen fertigation. CONCLUSION: The results of this study suggests that fertigation with 50% of the recommended fertilizer could be most effective for enhancing the growth and nitrogen use efficiency of rabbiteye blueberry.

• Korean Journal of Environment and Ecology
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• v.30 no.6
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• pp.962-969
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• 2016

This study assessed the ecological and behavioral characteristics of the sika deer from April 2012 to August 2016. To obtain basic information on the behavioral patterns of the sika deer (Cervus nippon) including their annual home range, sika deer wearing GPS tracking collars were released into 1,385 locations at a different altitude around where they had been captured in Songnisan. The released individuals were studied through home range analysis. According to our observations, annual home ranges of the sika deer (n=6) is seen to be $2.24{\pm}1.50km^2$ (t=3.648, p<0.05) of MCP 95% for the entire area of home range and $0.46{\pm}0.31km^2$ (t=3.666, p<0.05)$km^2$ of FK 50% for the home range core area respectively. The annual home ranges of the sika deers by sex were $2.94km^2$ for female and $1.53km^2$ for male. This study is expected to provide basic data for habitat management and ecological study of sika deer and to contribute to the management of wild animals.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.3
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• pp.374-380
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• 2015

This study firstly provides basic data for selection of cultivatable bioenergy grass in barren reclaimed lands applied with solidified sewage sludge. The experimental plots consisted of a plot containing reclaimed land mixed with solidified sewage sludge (MSS 50), a plot covered by solidified sewage sludge (CSS 100), and an original reclaimed soil plot (ORS). The growth, biomass production of bioenergy grasses and soil chemical properties were investigated in each experimental plot for 5 years. The organic matter (OM) and total nitrogen (T-N) content in both MSS 50 and CSS 100 were considerably higher than those in ORS. In bioenergy grasses, M. sacchariflorus cv. Geodae 1 showed an excellent growth and adaptability on reclaimed land applied with solidified sewage sludge. The application of solidified sewage sludge may provided soil nutrition in the reclaimed land due to the fact that bioenergy crops grew better in soils applied with solidified sewage sludge than in untreated soils, and treated soils had higher OM and T-N content than untreated soils. This study suggests that M. sacchariflorus cv. Geodae 1 is the most suitable biomass feedstock crop for biomass production and that solidified sewage sludge may be used as a soil material for cultivation of bioenergy grass on reclaimed lands.

• Korean Journal of Environment and Ecology
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• v.34 no.1
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• pp.9-17
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• 2020

Domestic cats (Felis catus) introduced to insular environments can be invasive predators that often threaten endemic species and cause biodiversity loss or local extinction on the island. This study was conducted from March to July 2018 to understand the population size, home range, and spatial use of cats introduced to Mara Islet (N 33° 07', E 126° 16') in Jeju Special Governing Province, the Republic of Korea. Observation records based on their natural marks revealed that there were 20 adult cats on Mara Islet. A capture-recapture method also estimated 20 adult individuals (95% confidence interval: 20-24 individuals). According to our telemetry study on ten adults deployed with GPS-based telemetry units, the home range size was 12.05±6.99 ha (95% KDE: kernel density estimation), and the core habitat size was 1.60±0.77 ha (50% KDE). There were no significant differences in the home range and core habitat sizes by sex. The home range of domestic cats overlapped with the human residential area, where they might secure easy foods. Five of ten tracked cats were active at potential breeding colonies for the Crested Murrlet (Synthliboramphus wumizusume), and six approached potential breeding areas of the Styan's Grasshopper Warbler (Locustella pleskei), suggesting the predation risk of the two endangered species by cats. This study provides novel information on the population size and home range of introduced cats on Mara Islet which is an important stopover site of migratory birds as well as a breeding habitat of the two endangered avian species. Reducing the potential negative impacts of the introduced cats on migratory birds and the endangered species on Mara Islet requires monitoring of the predation rate of birds by cats, the population trends of cats and endangered breeding birds as well as the effective cat population control and management.

• Korean Journal of Environment and Ecology
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• v.34 no.1
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• pp.1-8
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• 2020

This study conducted a full survey of the goral population using sensor cameras to identify the exact habitat of the gorals that inhabit Odaesan National Park and for restoration and habitat management-focused conservation projects following the population growth. We surveyed Odaesan National Park for a year in 2018 and selected18 grids (2km×2km) first based on the survey results. We then further divided each grid into four small grids (1km×1km) and installed a total of 62 sensor cameras in 38 small girds divided by four grids(1km×1km). The survey resulted in a total of 5,096 photographed wild animals, 2,268 of which were gorals, and the analysis by the classification table of goral (horn shape (Ⓐ), ring pattern (Ⓑ), ring formation ratio (Ⓒ), and facial color (Ⓓ)) identified a total of 95 animals. The ratio of male and female was 35 males (36.8%), 46 females (48.4%), and 14 sex unknowns (14.7%), while the ratio of female and male excluding sex unknowns was 4 (male):6 (female). The horn shape (Ⓐ) and face color (Ⓓ) were the important factors for distinguishing male and female and identifying individuals. The analysis of the correlation of 81 individuals, excluding 14 individuals of unknown sex, showed a significant difference (r=-0.635, p<0.01). Since the goral population in Odaesan National Park has reached a minimum viable population, it is necessary to change the focus of the management policy of Odaesan National Park from restoration to conservation.

• Tuberculosis and Respiratory Diseases
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• v.58 no.2
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• pp.160-166
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• 2005

Background : Although home oxygen therapy in hypoxemic patients with chronic lung disease has been increasing over the decade in Korea, the present state has not been known well. This study was done to know the situation of home oxygen therapy in a Korean university hospital. Methods : Between January 1, 2000 and August 31, 2003, 86 patients prescribed home oxygen therapy by the pulmonary physicians of Asan Medical Center were investigated using their medical record and questionnaire. Results : Patients (52 men, mean age of 61 years) with home oxygen therapy were increasing by every year. Underlying diseases were COPD (n=29), tuberculous destroyed lung (n=18), bronchiectasis (n=15), ILD (n=12), and others. Baseline $FEV_1/FVC$, FVC, and $FEV_1$ of patients were $58.4{\pm}25.2%$, $54.5{\pm}17.1%$ of predicted, and $41.7{\pm}20.6%$ of pred. Mean oxygen flow was 1.5 L/min and mean duration per day was 14.5 hours. During therapy, mean $PaO_2$ values have increased from 51.2 to 77.7 mm Hg and $PaCO_2$ values have increased from 47.5 to 49.6 mm Hg. Only 16.5% of the subjects were monitored by visiting nurses or pulse oximeter. Three year survival rate was 56.6% and hypercapnic patients showed better prognosis. Conclusion : The patients with home oxygen therapy were increasing yearly and a part of them were monitored. The hypercapnea respiratory failure patients would have better prognosis.

• Tuberculosis and Respiratory Diseases
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• v.61 no.3
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• pp.233-238
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• 2006

Study objectives: To determine the factors associated with mortality after an in-hospital diagnosis of tuberculosis in a region with low levels of HIV coinfection. Methods: From January 2003 to December 2004, all subjects who were > 15 years of age and had received a diagnosis of tuberculosis were registered. The clinical, radiological and laboratory aspects of the patients who died (n=27) were compared with those of an age and gender matched control population(n=54). Logistic regression analyses were carried out, which included age, gender, hospital admission source, initial site of admission, dyspnea, general weakness and initial laboratory data. Results: The mean age of the patients was $60{\pm}16$ years and male patients outnumbered female patients. Univariate analysis identified hemoglobin, blood urea nitrogen, albumin, cholesterol, aspartate aminotransferase (AST), C-reactive protein and the risk factors for tuberculosis to be significantly associated with mortality. Among the characteristics of disease presentation and treatment, emergency department admission, intensive care unit, disease severity, general weakness and dyspnea at the time of admission were associated with mortality. Multiple regression analysis revealed the initial management in the intensive care unit and lower serum albumin to be independently associated with mortality. Conclusion: The markers of disease chronicity and severity appear to be associated with in-hospital mortality. Identifying potentially reversible factors such as malnutrition and respiratory failure suggests specific intervention that might lead to an improvement in the patients' outcomes.