• Animal Bioscience
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• 제35권8호
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• pp.1223-1234
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• 2022

Objective: The objectives of this study were to evaluate the effects of daily feed intake during the laying period on embryonic myogenic differentiation 1 (MYOD1), myogenic factor 5 (MYF5), and myogenic factor 6 (MYF6) gene expression in genetically fat and lean lines of chickens. Methods: An experiment in a 2×2 factorial design was conducted with two dietary intake levels (100% and 75% of nutrition recommendation) and two broiler chicken lines (fat and lean). Two lines of hens (n = 384 for each line) at 23th week of age were randomly divided into 4 treatments with 12 replicates of 16 birds. The experiment started at 27th week of age (5% egg rate) and ended at 54th week of age. Hatched eggs from the medium laying period were collected. Real time polymerase chain reaction analysis was used to analyse the MYOD1, MYF5, and MYF6 mRNA levels of E7, E9, E11, E13, and E15 body tissues and E17, E19, and E21 chest and thigh muscle samples. Results: The results indicated that there were significant effects of line, dietary intake, and interactions between them on MYOD1, MYF5, and MYF6 gene mRNA expression levels in embryonic tissues. Low daily feed intake did not change the expression trend of MYOD1 mRNA in either line, but changed the peak values, especially in lean line. Low daily feed intake altered the trend in MYF5 mRNA expression level in both lines and apparently delayed its onset. There was no apparent effect of low daily feed intake on the trends of MYF6 mRNA expression levels in either line, but it significantly changed the values on many embryonic days. Conclusion: Maternal nutrient restriction affects myogenesis and is manifested in the expression of embryonic MYOD1, MYF5, and MYF6 genes. Long term selection for fat deposition in broiler chickens changes the pattern and intensity of myogenesis.

• Journal of Korea Entertainment Industry Association
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• 제15권2호
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• pp.149-157
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• 2021

One year has passed since the pandemic of COVID-19, which occurred in Wuhan, China, in November 2019 began. Worldwide, as of January 2021, more than 95 million people have been infected, and the death toll is higher than 2 million. In Korea, there are 74,262 infected and 1,328 dead, and government policies such as social distancing to prevent infection are being implemented. Accordingly, many inconveniences occurred in the physical activity environment, such as the closure of various sports facilities. It was necessary to consider physical activities to maintain healthy life while cooperating with the national policy while preventing infection. This study investigated the benefits of physical activity to reduce the risk of trichomoniasis and diabetes, improve bone mineral density, prolong healthy lifespan, maintain activity performance with aging, and improve psychological anxiety and depression. In addition, the physiological changes that may occur in the situation of stopping exercise due to social distancing to prevent COVID-19 infection were reviewed. In addition, moderate-intensity exercise that helps strengthen immune function by activating natural killer cells, neutrophils, and antibody responses was investigated. In addition, it reduces the level and function of blood B-cells, T-cells, and natural killer cells for several hours, decreases phagocytosis of neutrophils in the nasal cavity, increases inflammatory cytokines, decreases immune function, and increases infection. High-intensity exercise was considered. Therefore, in the age of COVID-19, long-term high-intensity exercise such as marathon, which causes impaired immune function, should be refrained from. And you should do moderate-intensity regular aerobic exercise such as fast walking to help prevent infection. It is also recommended to participate in resistance exercises to prevent loss of muscle mass.

• Korean Journal of Remote Sensing
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• 제38권6_1호
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• pp.1301-1314
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• 2022

Normalized Difference Vegetation Index (NDVI) is utilized as an indicator to represent the vegetation condition on the land surface in various applications such as land cover, crop yield, agricultural drought, soil moisture, and forest disaster. However, satellite optical sensors for visible and infrared rays cannot see through the clouds, so the NDVI of the cloud pixel is not a valid value for the land surface. This study proposed a real-time correction of the underestimation noise for GEO-KOMPSAT-2A (GK2A) daily NDVI and made sure its feasibility through the quantitative comparisons with Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI and the qualitative interpretation of time-series changes. The underestimation noise was effectively corrected by the procedures such as the time-series correction considering vegetation phenology, the outlier removal using long-term climatology, and the gap filling using rigorous statistical methods. The correlation with MODIS NDVI was higher, and the difference was lower, showing a 32.7% improvement compared to the original NDVI product. The proposed method has an extensibility for use in other satellite products with some modification.

• Economic and Environmental Geology
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• 제55권3호
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• pp.219-229
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• 2022

Bentonite is being considered as a candidate for buffer material in geological disposal systems for high-level radioactive wastes. In this study, the effect of cement-bentonite interactions on bentonite alteration was investigated by reviewing the literature on studies of cement-bentonite interactions. The major bentonite alteration by hyperalkaline fluids produced by the interaction of cementitious materials with groundwater includes cation exchange, montmorillonite dissolution, secondary mineral precipitation, and illitization. When the hyperalkaline leachate from the reaction of the cementitious material with the groundwater comes into contact with bentonite, montmorillonite, the main component of bentonite, is dissolved and a small amount of secondary minerals such as zeolite, calcium silicate hydrate, and calcite is produced. When montmorillonite is continuously dissolved, the physicochemical properties of bentonite may change, which may ultimately causes changes in bentonite performance as a buffer material such as adsorption capacity, swelling capacity, and hydraulic conductivity. In addition, the bentonite alteration is affected by various factors such as temperature, reaction period, pressure, composition of pore water, bentonite constituent minerals, chemical composition of montmorillonite, and types of interlayer cations. This study can be used as basic information for the long-term stability verification study of the buffer material in the geological disposal system for high-level radioactive wastes.

• Korean Journal of Applied Biomechanics
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• 제32권3호
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• pp.94-102
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• 2022

Objective: The purpose of this study was to investigate the effect of acute transcranial direct current stimulation (tDCS) on the isokinetic muscular endurance of the lower extremity for young adults. Method: Thirteen young adults performed isokinetic fatigue tasks for two experimental conditions including real tDCS and sham stimulation protocols. Before and after the task, the tensiomyography was used for evaluating muscle contraction characteristics of vastus medialis and semitendinosus. Paired t-test was performed to compare the fatigue index, changes in maximum radial displacement (∆Dm), delay time (∆Tc), and velocity of contraction (∆Vc) between tDCS conditions. Results: We found no significant differences in the fatigue index between real and sham conditions. In addition, the analyses identified no significant different values of ∆Dm, ∆Tc, and ∆Vc in the vastus medialis and semitendinosus between real and sham conditions. Conclusion: These findings suggest that the tDCS protocols may have no acute effect on lower limb muscle endurance for young adults. Future studies should consider the long-term effects of repetitive tDCS sessions, various stimulation positions, exercise tasks, and participant characteristics to more clearly understand the effect of tDCS on muscle endurance of lower extremities.

• Journal of the Korean Chemical Society
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• 제65권4호
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• pp.279-295
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• 2021

The purpose of this study was to investigate the effect of Character-centered instruction model on pre-service science teachers' awareness of both character education and character education in science education. First of all, pre-questionnaires about the sixteen pre-service science teachers' awareness of character education and character education in science education were asked. Through the lectures during a semester, they received an education about CoProC(Collaborative Problem-Solving for Character competence) model using Character-centered instruction model and character education. After the implementation, their changes of awareness were inspected through post-questionnaires. As a result of the study, it was revealed that general pre-service science teachers' pre-awareness of character education was mostly negative. The pre-service science teachers were more aware of character education in science classes than general character education. Even that, there seemed to be a greater tendency to think in connection with specific content and subject matter and character education rather than developing competencies due to the nature of the science subject itself. However, the experiences of the CoProC model changed their perception about character into a competent point of view, and thus influenced the change in their perception of character education. Therefore, education on character education methods for pre-service science teachers at teacher training institutions will increase their expertise in character education and help establish effective character education in school in the long term.

• Korean small business review
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• 제42권4호
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• pp.173-212
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• 2020

Interest in sustainable management based on the stakeholder perspective is expanding not only within an organization but also across the supply chain. For large companies that have established networks, sustainability management of the supply chain is now a factor that not only determines the social performance of the company as a whole, but also determines its long-term competitive position. Despite these changes in the business world, especially the proliferation of the sustainable supply chain management (SSCM) system, systematic research on SSCM has been lacking. In particular, there was a lack of empirical analysis on which factors promoted the establishment of the SSCM system for large companies and what's the effects of SSCM. In this regard, this study analyzes i) the impact of the social responsibility pressure of customers as external stakeholders and the CSR orientation of purchasing managers as internal stakeholders on supply chain transparency and partnership cooperation respectively, and ii) whether supply chain transparency and partnership cooperation can enhance corporate reputation. The samples used in this study were 69 large companies representing Korea. The results showed that the social responsibility pressure of customers and the purchasing manager's CSR orientation were positively related to the transparency of the supply chain. However, for partnership cooperation, only the purchasing manager's CSR orientation was found to have a positive and significant effect. Meanwhile, both supply chain transparency and partnership cooperation were positively related to the corporate reputation. At the end of the study, discussions on the implications of the results and future research directions will be presented.

• Journal of Korea Entertainment Industry Association
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• 제15권8호
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• pp.117-130
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• 2021

The government's social distancing policy and concerns about COVID-19 are increasing restrictions on outdoor leisure activities. Based on the decrease in outdoor leisure activities and the increase in indoor leisure activities, The purpose of this study is to examine the correlation between the degree of new confirmed cases of COVID-19 and the number of VOD views. This study conducted a time series analysis for 348 days from February 18, 2020 to January 31, 2021. Data were collected from the number of daily VOD views provided by the Korean Film Council and the number of new confirmed cases of COVID-19 provided by the Korea Centers for Disease Control and Prevention. The analysis showed that the number of confirmed COVID-19 cases has a significantly positive effect on the number of daily movie VOD views at the 5% significance level. This results indicate that the more confirmed cases of COVID-10, the more people watch movie VOD as indoor leisure activities. While previous studies examined the relationship between the confirmed cases of COVID-19 and indoor leisure activities in general, this study tried to academically contribute by analyzing the impact on specific indoor leisure activities. The practical implications of this study are as follows. The results of this study show that efficient promotions are possible based on significant social issues, such as infectious diseases. According to the results, promotions that respond quickly to changes are more effective than long-term promotions considering the climate or seasons. Due to the limitations of the data, the current study was conducted based only on PPV, but future research should also consider various billing forms such as PPM and SVOD.

• Environmental and Resource Economics Review
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• 제31권3호
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• pp.419-449
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• 2022

This paper aims to quantify the potential economic burdens of EU's carbon border adjustment mechanisms faced by Korean domestic industries. In addition, this study tries to compare and analyzes changes in the burden of each industry resulted from the implementation of the domestic low-carbon policy. Based on the quantitative findings, we intend to suggest policy implications for establishing mid- to long-term strategies in response to climate change risks. Based on the environmentally extended input-output analysis, the total economic burdens of the domestic industries due to the EU's carbon border adjustment mechanisms are estimated to be approximately KRW 8,245.6 billion in 2030. Looking at the impacts by industry, it is found that major industries such as petrochemicals, petroleum refining, transportation equipment, steel, automobiles, and electric/electronic equipment industries are expected to account for 84.3% of the total potential burdens. In addition, in multiple policy scenarios assuming technological developments and energy transition following the implementation of domestic low-carbon policies, the total economic burden of carbon border adjustment is expected to decrease by about 11.7% to 15.0%. The main result of this study suggests that we should not view EU EU's carbon border adjustment mechanism as a trade regulation, but to use it as a momentum for more effective implementation of the low-carbon and energy transition strategies in the global carbon neural era.

• The Journal of Engineering Geology
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• 제32권4호
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• pp.643-659
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• 2022

Geologic sequestration technologies such as CCS (carbon capture and storage), EGS (enhanced geothermal systems), and EOR (enhanced oil recovery) have been widely implemented in recent years, prompting evaluation of the mechanical stability of storage sites. As fluid injection can stimulate mechanical instability in storage layers by perturbing the stress state and pore pressure, poroelastic models considering various injection scenarios are required. In this study, we calculate the pore pressure, stress distribution, and vertical displacement along a surface using commercial finite element software (COMSOL); fault slips are subsequently simulated using PyLith, an open-source finite element software. The displacement fields, are obtained from PyLith is transferred back to COMSOL to determine changes in coseismic stresses and surface displacements. Our sequential use of COMSOL-PyLith-COMSOL for poroelastic modeling of fluid-injection and induced-earthquakes reveals large variations of pore pressure, vertical displacement, and Coulomb failure stress change during injection periods. On the other hand, the residual stress diffuses into the remote field after injection stops. This flow pattern suggests the necessity of numerical modeling and long-term monitoring, even after injection has stopped. We found that the time at which the Coulomb failure stress reaches the critical point greatly varies with the hydraulic and poroelastic properties (e.g., permeability and Biot-Willis coefficient) of the fault and injection layer. We suggest that an understanding of the detailed physical properties of the surrounding layer is important in selecting the injection site. Our numerical results showing the surface displacement and deviatoric stress distribution with different amounts of fault slip highlight the need to test more variable fault slip scenarios.