• Journal of Marine Life Science
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• v.5 no.1
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• pp.25-33
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• 2020

The Asan Bay, which has semi-diurnal tide with macro-tidal range, is affected by both freshwater discharge from the sluice gates in the sea dikes and tidal seawater inputs from the Yellow sea. Understanding water quality change in response to tides is important since tides can impact the short-term variations in physical and chemical water properties as well as the response of biological properties. The diel variations in water quality were seasonally investigated at 2 hour intervals from a fixed station in the Asan Bay. In the results, water temperature and salinity consistently fluctuated in phase or out of phase with tidal height. Especially salinity was positively correlated with tidal height. The concentrations of total suspended solids were higher in the bottom water than in the surface and fluctuated greatly over the tidal cycle recording higher values at low tide than at high tide. Nitrite+nitrate levels also fluctuated out of phase with tidal height and correlated negatively with tidal height. Other nutrients also showed a similar pattern. The pattern was distinct in July when freshwater was discharged before the field sampling. The concentrations of organic materials, total nitrogen and total phosphorus greatly fluctuated over the tidal cycle and were generally out of phase with tidal height. Most materials except particulate organic forms were correlated with salinity indicating that freshwater inputs were sources for the materials similarly to the dissolved inorganic nutrients. The results suggest that water quality (except dissolved oxygen and pH) and nutrients including organic materials was largely affected by tides in the Asan Bay.

• Journal of Korea Water Resources Association
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• v.51 no.spc
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• pp.1079-1089
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• 2018

The majority of existing studies for quantifying uncertainties in climate change impact assessments suggest only the uncertainties of each stage, and not the total uncertainty and its propagation in the whole procedure. Therefore, this study has proposed a new method, the Uncertainty Delta Method (UDM), which can quantify uncertainties using the variances of projections (as the UDM is derived from the first-order Taylor series expansion), to allow for a comprehensive quantification of uncertainty at each stage and also to provide the levels of uncertainty propagation, as follows: total uncertainty, the level of uncertainty increase at each stage, and the percentage of uncertainty at each stage. For quantifying uncertainties at each stage as well as the total uncertainty, all the stages - two emission scenarios (ES), three Global Climate Models (GCMs), two downscaling techniques, and two hydrological models - of the climate change assessment for water resources are conducted. The total uncertainty took 5.45, and the ESs had the largest uncertainty (4.45). Additionally, uncertainties are propagated stage by stage because of their gradual increase: 5.45 in total uncertainty consisted of 4.45 in emission scenarios, 0.45 in climate models, 0.27 in downscaling techniques, and 0.28 in hydrological models. These results indicate the projection of future water resources can be very different depending on which emission scenarios are selected. Moreover, using Fractional Uncertainty Method (FUM) by Hawkins and Sutton (2009), the major uncertainty contributor (emission scenario: FUM uncertainty 0.52) matched with the results of UDM. Therefore, the UDM proposed by this study can support comprehension and appropriate analysis of the uncertainty surrounding the climate change impact assessment, and make possible a better understanding of the water resources projection for future climate change.

• Korean Journal of Environmental Biology
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• v.37 no.1
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• pp.72-81
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• 2019

Bisphenol A (BPA), a representative endocrine disrupting chemicals, has adverse effects on growth, development and reproduction in aquatic organisms. The object of this study was to investigate the modulation of antioxidant enzyme-coding genes using quantitative real time RT-PCR (qRT-PCR), enzyme activity and total protein content, to understand oxidative stress responses after exposure to BPA for 48 h in brackish water flea Diaphanosoma celebensis. The BPA ($3mg\;L^{-1}$) significantly upregulated the expression of Cu/Zn-SOD, Mn-SOD, and catalase (CAT) mRNA. Three GST isoforms (GST-kappa, GST-mu, and GST-theta) mRNA levels significantly increased at the rate of $0.12mg\;L^{-1}$ of BPA. In particular, GST-mu showed the highest expression level, indicating its key role in antioxidant response to BPA. SOD activity was induced with a concentration-dependent manner, and total protein contents was reduced. These findings indicate that BPA can induce oxidative stress in this species, and these antioxidants may be involved in cellular protection against BPA exposure. This study will provide a better understanding of molecular mode of action of BPA toxicity in aquatic organisms.

• Korean Journal of Ecology and Environment
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• v.52 no.2
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• pp.94-104
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• 2019

In this study, we investigated the spatial variation in land use and topographic effects on water quality at the Geum river watershed in South Korea, using the ordinary least squares(OLS) and geographically weighted regression (GWR) models. Understanding the complex interactions between land use, slope, elevation, and water quality is essential for water pollution control and watershed management. We monitored four water quality indicators -total phosphorus, total nitrogen, biochemical oxygen demand, and dissolved oxygen levels - across three land use types (urban, agricultural, and forested) and two topographic features (elevation and mean slope). Results from GWR modeling revealed that land use and topography did not affect water quality consistently through space, but instead exhibited substantial spatial non-stationarity. The GWR model performed better than the OLS model as it produced a higher adjusted $R^2$ value. Spatial variation in interactions among variables could be visualized by mapping $R^2$ values from the GWR model at fine spatial resolution. Using the GWR model, we were able to identify local pollution sources, determine habitat status, and recommend appropriate land-use planning policies for watershed management.

• Management & Information Systems Review
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• v.38 no.1
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• pp.121-139
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• 2019

This study aims to identify the change of customer participation(CP) which is essential to the service industry as the relationship between the customer and the employee develops. The latent growth modeling analysis based on the longitudinal data is utilized to examine the pattern of the change. This is based on the fact that CP needs to be understood in the relationship and is to confirm the change in CP by the development of the relationship. Given the dynamics of the relationship, we intend to overcome the limitations of previous cross-sectional researches by revealing the trajectory of CP in the relationship through the longitudinal data. We also want to examine which variables in the relationship can facilitate changes of CP. Research has shown that CP is significantly changed with the development of the relationship when we analyzed it through latent growth modeling. This confirms that CP needs to be understood in the relationship. In addition, 'relationship proneness' variable and 'dependence to provider' variable have positive effects on the initial values of CP, but they have not been established to promote the changes of CP. Consequently, when considering the dynamics of relationships, it is important to recognize that CP is also dynamic. This study sought to get out of the cross-sectional and fragmented understanding of CP that is dynamic. Through this, we would like to propose the successful operation of the customer management program of service firms in relation to CP. This will lead to the success of service encounter where appropriate CP levels at each stage of relationship development can be achieved.

• Korean Journal of Plant Taxonomy
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• v.49 no.1
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• pp.28-69
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• 2019

We conducted taxonomical investigations based on morphological characteristics, fruit morphology, and literature research on the tribe Potentilleae (Rosaceae) in Korea covering seven genera and 24 species. The style position on the ovary and the shape of style were useful characteristics for the classification of subtribal and generic levels in the tribe Potentilleae. The subtribe Fragariinae is characterized by subbasal or lateral style on the ovary and anthers with one theca. The subtribe Potentillinae has a subterminal style on the ovary, except for Argentina, which presents a subterminal and lateral style and anthers with two thecae. These results support the recent taxonomic recognition that i) the tribe Potentilleae consists of two subtribes, and ii) genera such as Dasiphora, Comarum, and Sibbaldianthe sometimes included in Potentilla s.l. are treated as independent genus. In the subtribe Potentillinae, Argentina, which has been treated as Potentilla, is supported as a distinct genus according to the characteristics of the subterminal and lateral style position and the ventral stipular auricles. In Fragaria, F. nipponica subsp. chejuensis, which has generally small leaves and a limited distribution only on Hallasan Mt., is supported by treatment as an endemic species. Duchesnea chrysantha is distinguished from D. indica by the characteristics of light green or yellowish green leaves, thin and somewhat membranous leaflets, and broad ovate or obovate leaflets. Each complex of P. dickinsii and P. chinensis remains unresolved with regard to controversy over the taxonomic circumscription due to their external morphological variations. Additional taxonomical research and molecular population studies are required for a more in-depth understanding of the tribe Potentilleae in Korea.

• The Journal of the Korea Contents Association
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• v.19 no.5
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• pp.484-496
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• 2019

The purpose of this study is to identify the factors influencing conflict transition through the conflict transition process experienced by college graduates with early careers. The participants of this study were in-depth interviews with a total of 8 young people aged 25-34 who graduated from college and found their common subjects in all cases. As a result, the topics such as 'lack of recognition and compensation', 'unfairness of supervisor', 'characteristics of job (interdependence, autonomy)' were derived. 'Lack of recognition and compensation' brought about a sense of skepticism about the idea that even though they worked hard, they could not be recognized. And it caused a conflict transition. When the participants felt the 'unfairness of the supervisor', the task conflicts were further amplified and it transfer to relationship conflict. Among the characteristics of 'job characteristics', when highly interdependent occupations were carried out, conflict transition was shown and conflict levels were high. On the other hand, the work environment with job autonomy showed job satisfaction and did not show conflict transition. This study has an academic significance in that it revealed the types of conflicts and conflict transfer factors experienced in early career status of college graduates. In addition, this research have the practical implications to improves the participants' understanding of the conflict transfer through actual scene in the workplace.

• Animal Bioscience
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• v.34 no.4
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• pp.525-532
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• 2021

Objective: Old World camels are a valuable genetic resource for many countries around the world due to their adaptation to the desert environment. At present, Old World camels have encountered the challenge of unprecedented loss of genetic resources. Through our research, we would reveal the population structure and genetic variation in Old World camel populations, which provides a theoretical basis for understanding the germplasm resources and origin and evolution of different Old World camel populations. Methods: In the present study, we assessed mtDNA control region sequences of 182 individuals from Old World camels to unravel genetic diversity, phylogeography, and demographic dynamics. Results: Thirty-two haplotypes confirmed by 54 polymorphic sites were identified in the 156 sequences, which included 129 domestic and 27 wild Bactrian camels. Meanwhile, 14 haplotypes were defined by 47 polymorphic sites from 26 sequences in the dromedaries. The wild Bactrian camel population showed the lowest haplotype and nucleotide diversity, while the dromedaries investigated had the highest. The phylogenetic analysis suggests that there are several shared haplotypes in different Bactrian camel populations, and that there has been genetic introgression between domestic Bactrian camels and dromedaries. In addition, positive values of Tajima's D and Fu's Fs test demonstrated a decrease in population size and/or balancing selection in the wild Bactrian camel population. In contrast, the negative values of Tajima's D and Fu's Fs test in East Asian Bactrian camel populations explained the demographic expansion and/or positive selection. Conclusion: In summary, we report novel information regarding the genetic diversity, population structure and demographic dynamics of Old World camels. The findings obtained from the present study reveal that abundant genetic diversity occurs in domestic Bactrian camel populations and dromedaries, while there are low levels of haplotype and nucleotide diversity in the wild Bactrian camel population.

• Journal of Astronomy and Space Sciences
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• v.38 no.1
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• pp.31-38
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• 2021

In this paper, we present observations of the Space Radiation Detectors (SRDs) onboard the Next Generation Small Satellite-1 (NEXTSat-1) satellite. The SRDs, which are a part of the Instruments for the study of Stable/Storm-time Space (ISSS), consist of the Medium-Energy Particle Detector (MEPD) and the High-Energy Particle Detector (HEPD). The MEPD can detect electrons, ions, and neutrals with energies ranging from 20 to 400 keV, and the HEPD can detect electrons over an energy range from 0.35 to 2 MeV. In this paper, we report an event where particle flux enhancements due to substorm injections are clearly identified in the MEPD A observations at energies of tens of keV. Additionally, we report a specific example observation of the electron distributions over a wide energy range in which we identify electron spatial distributions with energies of tens to hundreds of keV from the MEPD and with energy ranging up to a few MeV from the HEPD in the slot region and outer radiation belts. In addition, for an ~1.5-year period, we confirm that the HEPD successfully observed the well-known outer radiation belt electron flux distributions and their variations in time and L shell in a way consistent with the geomagnetic disturbance levels. Last, we find that the inner edge of the outer radiation belt is mostly coincident with the plasmapause locations in L, somewhat more consistent at subrelativistic energies than at relativistic energies. Based on these example events, we conclude that the SRD observations are of reliable quality, so they are useful for understanding the dynamics of the inner magnetosphere, including substorms and radiation belt variations.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.1
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• pp.75-81
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• 2022

Given that China's resource research, exploration and development and resource economy policies are closely related to Korea's industrial competitiveness in the field of global mineral energy resources, it is important to establish the domestic and overseas resource development strategies. In 2020, China will revise and set standards for mineral resources to ensure efficiency in exploration and development and storage management. China's Ministry of Natural Resources has established the National Mineral Resources Plan (2021-2025), aiming to achieve national goals and strategies, and local governments at all levels are also establishing and implementing regional mineral resources plans. As a result, the supervision and management of geological mineral exploration activities have been strengthened, and the safety of industrial production management in the field of geological mineral exploration and development has been strengthened. China has developed guidelines for high-quality geological exploration, surveying and mapping, improved the level of geological mineral exploration and strengthened the mining supervision and management system. According to China's standardization of mineral resources such as solid mineral resources and petroleum gas mineral resources, a new standard system for resource management will be established in China to improve scientific understanding, rational management and utilization.