• Journal of Korean Society of Forest Science
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• v.113 no.2
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• pp.222-238
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• 2024

Coniferous species in subalpine ecosystems are known to be highly sensitive to climate change. Therefore, it is becoming increasingly important to monitor community and population dynamics. This study monitored 37 plots within the distribution area of Abies koreana on Mt. Jirisan for a period of eight years. We analyzed the importance value, density of living stems, mortality rate, recruitment rate, basal area, DBH (diameter of breast height) class distribution, and tree health status. Our results showed changes in the importance value based on the tree stratum, with A. koreana decreasing by 3.6% and Tripterygium regelii increasing by 2.5% in the tree layer. Between 2015 and 2023, there were 149 dead trees/ha (17.99% mortality rate) and 12 living trees/ha (1.02% recruitment rate) of A. koreana. The decrease in basal area was attributed to a decrease in the number of living trees. Tree mortality occurred in all DBH classes, with a particularly high decline in the <10 cm class (65 trees/ha reduced). In terms of changes in tree health status, the population of alive standing (AS) type trees, initially consisting of 539 trees/ha, has been transformed into alive standing (AS), alive lean (AL), and death standing (DS), accounting for 69.7%, 0.5%, and 13.8%, respectively. Meanwhile, DS-type trees have transitioned into dead broken (DB) and dead fallen (DF) types. This phenomenon is believed to be caused by strong winds in the subalpine region that pull up the rootlets from the soil. Further research on this finding is recommended.

• Research in Plant Disease
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• v.30 no.2
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• pp.139-147
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• 2024

Erwinia amylovora is a gram-negative plant pathogen that causes fire blight in apple and pear trees, resulting in significant damage worldwide. In this study, we monitored the emergence of fire blight from 2019 to 2023 to determine the emergence patterns and the factors affecting the outbreak of the disease. As a result of the 5-year survey on the emergence of fire blight, a total of 2,029 cases have emerged, mostly in apple trees of 1,378 cases (67.9%) followed by 645 cases (31.8%) in pear trees, and from quince, hawthorn, and mountain ash trees. Fire blight appeared in specific areas of Gyeonggi, Chungnam, Gangwon, and Chungbuk provinces in 2019, but spread to Andong and Yesan in 2021, Muju and Bonghwa in 2023. In 2020 and 2021, there were 744 and 618 cases of fire blight outbreaks, respectively, compared to other years (188-245 cases/year). Notably, 914 of these cases were observed in apple trees from May to July, with 667 cases reported in Chungju and Jecheon. The incidence of fire blight was positively correlated with the daily maximum temperatures and rainy days in January and February, as well as the rainy days in May and June. The average age of the diseased pear trees was 25 years, higher than the 10-year average age of the apple trees. This study provides fundamental information to understand the status and factors affecting the fire blight emergence in Korea. Prevention measures should be established through continuous analysis of the status of fire blight.

• Journal of Food Hygiene and Safety
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• v.39 no.3
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• pp.221-230
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• 2024

Pesticide residues were monitored in dried red pepper and pepper powder samples purchased in Northern Gyeonggi-do and from domestic online markets. The QuEChERS method was used to prepare 88 samples. GC-MS/MS and LC-MS/MS were used to analyze 338 pesticide residues. In the study, pesticide residues were detected in 70 samples (79.5%), with residues exceeding the maximum residue limits (MRL) in 4 samples (4.5%). Pesticide levels exceeded the MRL in imported samples, with two samples of dried red pepper and two samples of pepper powder showing elevated levels. Among the 61 pesticides detected, tebuconazole, a fungicide was most frequently detected (52 times). Tricyclazole, which is used to control the main disease affecting rice, exceeding the MRL in 3 of 12 Vietnam-origin samples. Ethion exceeded the MRL in one Indian-origin sample. Both tricyclazole and ethion are banned for use in pepper products in Korea and are regulated under the positive list system (PLS). Conversely, pesticides detected in domestic samples were within the MRLs. Therefore, authorities should monitor pesticide residues in imported red pepper products.

• Korean Journal of Remote Sensing
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• v.40 no.4
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• pp.363-375
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• 2024

Waterbody change detection using satellite images has recently been carried out in various regions in South Korea, utilizing multiple types of sensors. This study utilizes optical satellite images from Landsat and Sentinel-2 based on Google Earth Engine (GEE) to analyze long-term surface water area changes in four monitored small and medium-sized water supply dams and agricultural reservoirs in South Korea. The analysis covers 19 years for the water supply dams and 27 years for the agricultural reservoirs. By employing image analysis methods such as normalized difference water index, Canny Edge Detection, and Otsu'sthresholding for waterbody detection, the study reliably extracted water surface areas, allowing for clear annual changes in waterbodies to be observed. When comparing the time series data of surface water areas derived from satellite images to actual measured water levels, a high correlation coefficient above 0.8 was found for the water supply dams. However, the agricultural reservoirs showed a lower correlation, between 0.5 and 0.7, attributed to the characteristics of agricultural reservoir management and the inadequacy of comparative data rather than the satellite image analysis itself. The analysis also revealed several inconsistencies in the results for smaller reservoirs, indicating the need for further studies on these reservoirs. The changes in surface water area, calculated using GEE, provide valuable spatial information on waterbody changes across the entire watershed, which cannot be identified solely by measuring water levels. This highlights the usefulness of efficiently processing extensive long-term satellite imagery data. Based on these findings, it is expected that future research could apply this method to a larger number of dam reservoirs with varying sizes,shapes, and monitoring statuses, potentially yielding additional insights into different reservoir groups.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.4
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• pp.31-37
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• 2010

Livestock manures have a potential to be a valuable resource with an efficient treatment. In Korea, 42 million tons of livestock manure were generated in 2008, and 84 % of them were used for compost and liquid fertilizer production. Recently recycling of livestock manure for biogas production through anaerobic digestion is increasing, but its utilization in agriculture is still uncertified. In this study, there was applied co-digestate to the paddy for rice cultivation based on N supplement. Co-digestate was fertilizer fermented with pig slurry and food waste combined with the ratio of 70:30(v:v) in its volumetric basis. For assessing the safety of co-digestate, it was monitored the contents of co-digestate for seasonal variation, resulted in no potential harm to the soil and plant by heavy metals. The results showed that soil applied with co-digestate was increased in exchangeable potassium, copper and zinc mainly due to the high rate of pig slurry in co-digestate applied. Considering high salt content due to the combination with food waste, strict quality assurances are needed for safe application to arable land though it has valuable fertilizer nutrient. Leachate after treatment showed that the concentration of nitrate nitrogen washed out within two weeks. Considering the salt accumulation results in soil, it is highly recommended that the application rate of co-digestate should not exceed the crop fertilization rate based on N supplement. With these results, it was concluded that co-digestate could be used as an alternative fertilizer for chemical fertilizer. More study is needed for the long-term effects of co-digestate application on the soil and water environment.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.1
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• pp.41-49
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• 2003

Methane emission was measured in a rice paddy under different water management and organic amendments. Methane emission from planted chambers and unplanted chambers was monitored to evaluate the rice-mediated methane emission. In flooding methane emission from planted chambers with NPK, NPK(+P), was $0.174g\;CH_4\;m^{-2}\;d^{-1}$ while that from unplanted chambers with NPK, NPK(-P), was $0.046g\;CH_4\;m^{-2}\;d^{-1}$ Methane emission from planted chambers with rice straw compost amendment, RSC(+P), was $0.214g\;CH_4\;m^{-2}\;d^{-1}$, while that from unplanted chambers with rice straw compost amendment, RSC(-P), was $0.076g\;CH_4\;m^{-2}\;d^{-1}$. Methane emission from planted chambers with rice straw amendment in Fehruary, RS2(+P), was $0.328g\;CH_4\;m^{-2}\;d^{-1}$, while that from unplanted chambers with rice straw amendment in February, RS2(-P), was $0.1g\;CH_4\;m^{-2}\;d^{-1}$. Methane emission from planted chambers with rice straw amendment in May, RS5(+P), was $0.414g\;CH_4\;m^{-2}\;d^{-1}$, while that from unplanted chamhers with rice straw amendment in May, RS5(-P), was $0.187g\;CH_4\;m^{-2}\;d^{-1}$. In intermittent irrigation methane emission from NPK(+P) was $0.115g\;CH_4\;m^{-2}\;d^{-1}$, while that from NPK(-P) was $0.041g\;CH_4\;m^{-2}\;d^{-1}$. Methane emission from RSC(+P) was $0.137g\;CH_4\;m^{-2}\;d^{-1}$, while that from RSC(-P) was $0.06g\;CH_4\;m^{-2}\;d^{-1}$. Methane emission from RS2(+P) was $0.204g\;CH_4\;m^{-2}\;d^{-1}$, while that from RS2(-P) was $0.09g\;CH_4\;m^{-2}\;d^{-1}$. Methane emission from RS5(+P) was $0.273g\;CH_4\;m^{-2}\;d^{-1}$, while that from RS5(-P) was $0.13g\;CH_4\;m^{-2}\;d^{-1}$. Methane transport via rice plant under flooding for NPK plot, RSC plot, RS2 plot and RS5 plot was 73.6%, 64.5%, 69.5% and 54.8%, respectively, and mean was 65.6%. Methane transport via rice plants under intermittent irrigation for NPK plot, RSC plot, RS2 plot and RS5 plot was 64.3%, 59.2%, 55.9% and 52.4%, respectively, and mean was 58.0%.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.5
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• pp.80-88
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• 2020

With the issuance of one-week fine dust emergency reduction measures in March 2019, the public's anxiety about fine dust is increasingly growing. In order to assess the application of air purifying plant-based bio-filters to public facilities, this study presented a method for measuring pollutant reduction effects by creating an indoor environment for continuous discharge of particle pollutants and conducted basic studies to verify whether indoor air quality has improved through the system. In this study conducted in a lecture room in spring, the background concentration was created by using mosquito repellent incense as a pollutant one hour before monitoring. Then, according to the schedule, the fine dust reduction capacity was monitored by irrigating for two hours and venting air for one hour. PM₁₀, PM_2.5, and temperature & humidity sensors were installed two meters front of the bio-filters, and velocity probes were installed at the center of the three air vents to conduct time-series monitoring. The average face velocity of three air vents set up in the bio-filter was 0.38±0.16 m/s. Total air-conditioning air volume was calculated at 776.89±320.16㎥/h by applying an air vent area of 0.29m×0.65m after deducing damper area. With the system in operation, average temperature and average relative humidity were maintained at 21.5-22.3℃, and 63.79-73.6%, respectively, which indicates that it satisfies temperature and humidity range of various conditions of preceding studies. When the effects of raising relatively humidity rapidly by operating system's air-conditioning function are used efficiently, it would be possible to reduce indoor fine dust and maintain appropriate relative humidity seasonally. Concentration of fine dust increased the same in all cycles before operating the bio-filter system. After operating the system, in cycle 1 blast section (C-1, β=-3.83, β=-2.45), particulate matters (PM₁₀) were lowered by up to 28.8% or 560.3㎍/㎥ and fine particulate matters (PM_2.5) were reduced by up to 28.0% or 350.0㎍/㎥. Then, the concentration of find dust (PM₁₀, PM_2.5) was reduced by up to 32.6% or 647.0㎍/㎥ and 32.4% or 401.3㎍/㎥ respectively through reduction in cycle 2 blast section (C-2, β=-5.50, β=-3.30) and up to 30.8% or 732.7㎍/㎥ and 31.0% or 459.3㎍/㎥ respectively through reduction in cycle 3 blast section (C-3, β=5.48, β=-3.51). By referring to standards and regulations related to the installation of vegetation bio-filters in public facilities, this study provided plans on how to set up objective performance evaluation environment. By doing so, it was possible to create monitoring infrastructure more objective than a regular lecture room environment and secure relatively reliable data.

• Korean Journal of Poultry Science
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• v.35 no.3
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• pp.291-302
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• 2008

To acquire essentially necessary basic data to establish feeding system by verifying appropriate dietary energy and protein level for the growth of commercial slow growing broiler chicks within the country, two experiments were conducted for 5 weeks. One day old, 1,404 male and female broiler chicks were used for the experiments, and 26 chicks were placed at each pen. The energy level of feed was maintained about 3,000 or 3,100 kg/kcal for whole breeding period of 5 weeks, and protein content was adjusted about 20, 21, and 22% during the first two weeks and the content was adjusted to 18, 19, 20, 21, and 22% from the 3 to 5 weeks old of the experiment. The categories of body weight and feed intake amount were monitored to calculate the productivity and blood sampling was conducted for the analysis at the end of each experiment. Experiment 1:Although the productivity by the ME content difference during $0{\sim}2$ weeks did not have significant difference and the body weight increase by the difference of CP content and feed intake amount did not have much difference, the feed requirement rate was statistically improved in CP 21 and 22% treatment groups compared to the CP 20% group (P<0.05). The feed ME 3,100 kcal/kg treated group during $3{\sim}5$ weeks after starting the experiment revealed to show improved feed requirement rate (P<0.05). Within the period of experiment, the CP 22% treated group resulted to show significant body weight increase compared to the groups treated with low levels of CP (P<0.05) and the feed requirement rate was improved in high CP treated group compared to low CP treated groups, but the feed intake amount did not show significant difference between treated groups. During the experiment period, the body weight increase and feed requirement rate revealed to interact between ME and CP (P<0.05). During the whole experiment period of the 5 weeks, the feed requirement rate was improved in ME 3,100 kcal/kg treated group than the groups treated with ME 3,000 kcal/kg, and the CP (20) 18% treatment groups resulted to show higher values than other treatment groups (P<0.05). Body weight increase was high in CP (22) 22% treated groups than those of CP (21) 21% and (20) 18% treated groups, and the interaction between ME and CP was found at body weight increase and feed requirement rate (P<0.05). Although blood albumin and total cholesterol levels were elevated in ME 3,100 kcal/kg treated group than ME 3,000 kcal/kg treated group, but neutral fat content was reduced (P<0.05). On the other hand, the total cholesterol content was increased in CP (22) 21% treated group than CP (22) 20% and CP (20) 18% treated groups (P<0.05). Experiment 2: The body weight increase in 0-2 weeks was higher in ME 3,100 kcal/kg treated group than ME 3,000 kcal/kg treated group, and it was highly improved in CP 22% treated group than CP 20% treated group by showing the interaction between CP and ME (P<0.05). The significant improvement of feed requirement rate was observed in CP 21% and 22% treated groups compared to CP 20% treated group (P<0.05). The productivity between the growth period from 3 to 5 weeks of age and whole growth period resulted to show no significant difference. Although no difference was observed in blood composition between treated groups, the interaction of ME and CP on cholesterol content was accepted at the range of P<0.05). Therefore, it is considered that the appropriate dietary protein level within feed for the physiology of growing broiler chicks was 22% or more for the first two weeks and protein level of 21% or 20% from 3 to 5 weeks old for the maximization of productivity. Even if the energy level within feed had some partial effects on the productivity, but did not show consistency. So, further experiments needto be conducted by differentiating the energy level.

• Pediatric Infection and Vaccine
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• v.10 no.1
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• pp.71-80
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• 2003

Purpose : Four kinds of Haemophilus influenzae type b protein conjugate vaccines, PRPD, PRP-T, PRP-OMP and PRP-CRM197, have been developed, and PRP-T vaccines are currently produced by two manufacturer, $ActHib^{(R)}$ by Aventis and $Hiberix^{TM}$ by GlaxoSmith-Kline Biologicals. The purpose of this study is to evaluate the immunogenicity and safety of $Hiberix^{TM}$ in Korean infants. Methods : Seventy-three healthy infants(43 male infants) were recruited for this study after parental informed consent was obtained. Each infant was vaccinated at 2, 4 and 6 months of age with the study vaccine. At each visit, infants were also immunized with DTaP, trivalent oral polio vaccine and hepatitis B vaccine when indicated. The serum anti-PRP antibody was measured at prevaccination, 2 month later after the 2nd dose, and 1 month later after the 3rd dose by the ELISA method. The local and systemic adverse reactions of vaccination were monitored for 3 consecutive days after each immunization. Immunogenicity of vaccine was evaluated in infants who received all the scheduled immunization and the adverse reactions were evaluated for infants who received at least one dose of the study vaccine. Results : Among seventy three infants, enrolled in this study; sixty three(37 male infants) completed all the scheduled immunizations. The geometric mean titer(GMT) of anti-PRP antibodies at prevaccination was 0.17 ${\mu}g/mL$(95% confidence interval[CI]; 0.13~0.22). The GMT of anti-PRP antibodies increased to 4.14 ${\mu}g/mL$(95% CI; 2.65~6.48) at 2 month later after the 2nd dose of PRP-T and 14.65 ${\mu}g/mL$(95% CI; 10.83~19.81) at 1 month later after the 3rd dose. Anti-PRP antibody ${\geq}0.15$ ${\mu}g/mL$, was observed in 98.4%(95% CI; 91.8~100) after 2 doses and 100%(95% CI; 100~100) after 3 doses. Anti-PRP antibody ${\geq}1.0$ ${\mu}g/mL$, was obtained in 77.8%(95% CI; 67.5~88.0) after 2 doses, and 98.4%(95% CI; 95.3~100) after 3 doses. Most of the adverse reaction after vaccination were mild. Irritability, the most common systemic reaction, was observed in 45.5%, followed by drowsiness(30.5%), poor feeding(26.7%) and fever(5.6%). Among the local reactions tenderness was observed in 7.9%, redness(${\geq}5$ mm) in 2.8% and swelling(${\geq}5$ mm) in 1.8%. Conclusion : The PRP-T vaccine used in this study was highly immunogenic and safe in Korean young infants. The finding that high GMT and high frequency of infants with a protective titer achieved after 2 doses is consistent with the previous studies which were done with a PRP-T vaccine of other manufacturer. This study suggests that the immunization schedule of PRP-T vaccine for Korean infants may need re-evaluation.

• The Journal of Engineering Geology
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• v.28 no.2
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• pp.217-246
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• 2018

During the selection and characterization of target formations in the Small-scale Offshore $CO_2$ Storage Demonstration Project in the Pohang Basin, we have carefully investigated the possibility of induced earthquakes and leakage of $CO_2$ during the injection, and have designed the storage processes to minimize these effects. However, people in Pohang city have a great concern on $CO_2$-injection-intrigued seismicity, since they have greatly suffered from the 5.4 magnitude earthquake on Nov. 15, 2017. The research team of the project performed an extensive self-investigation on the safety issues, especially on the possible $CO_2$ leakage from the target formation and induced earthquakes. The target formation is 10 km apart from the epicenter of the Pohang earthquake and the depth is also quite shallow, only 750 to 800 m from the sea bottom. The project performed a pilot injection in the target formation from Jan. 12 to Mar. 12, 2017, which implies that there are no direct correlation of the Pohang earthquake on Nov. 15, 2017. In addition, the $CO_2$ injection of the storage project does not fracture rock formations, instead, the supercritical $CO_2$ fluid replaces formation water in the pore space gradually. The self-investigation results show that there is almost no chance for the injection to induce significant earthquakes unless injection lasts for a very long time to build a very high pore pressure, which can be easily monitored. The amount of injected $CO_2$ in the project was around 100 metric-tonne that is irrelevant to the Pohang earthquake. The investigation result on long-term safety also shows that the induced earthquakes or the reactivation of existing faults can be prevented successfully when the injection pressure is controlled not to demage cap-rock formation nor exceed Coulomb stresses of existing faults. The project has been performing extensive studies on critical stress for fracturing neighboring formations, reactivation stress of existing faults, well-completion processes to minimize possible leakage, transport/leakage monitoring of injected $CO_2$, and operation procedures for ensuring the storage safety. These extensive studies showed that there will be little chance in $CO_2$ leakage that affects human life. In conclusion, the Small-scale Offshore $CO_2$ Storage Demonstration Project in the Pohang Basin would not cause any induced earthquakes nor signifiant $CO_2$ leakage that people can sense. The research team will give every effort to secure the safety of the storage site.