• Journal of Dental Anesthesia and Pain Medicine
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• v.16 no.1
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• pp.25-29
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• 2016

Background: The most important reason for pre-operative administration of medication is to reduce anxiety. Alleviation of fear and anxiety about surgery enables patients to remain comfortable during treatment. Dexmedetomidine (DEX) is a fast-acting drug that is used as a premedication in different circumstances because it has sedative and anti-anxiolytic effects, and stable hemodynamics. It also has the advantage of intranasal administration. The aim of this study was to investigate the effects and hemodynamic stability of DEX by retrospectively analyzing cases in which DEX was administered nasally as a premedication. Methods: Ten patients treated at Dankook University Dental Hospital, recruited between February and April 2015, received intranasal delivery of $2{\mu}g/kg$ DEX, 30 minutes prior to general anesthesia. Anesthesia records of anxiety, blood pressure, respiration, pulse, estimated arterial oxygen saturation ($SpO_2$), and partial pressure, or maximum concentration, of carbon dioxide ($ETCO_2$) were analyzed. Results: Administration of DEX prior to a general anesthetic effectively relieved anxiety. Respiratory depression, the most severe adverse effect of other sedatives, was not observed. Hemodynamic stability under general anesthesia was maintained during treatment and a reduction in emergence delirium was observed upon completion of treatment. Conclusions: Premedication administration of DEX is safe for pediatric patients undergoing dental treatment under general anesthesia.

• Journal of Animal Science and Technology
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• v.53 no.5
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• pp.475-480
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• 2011

This study was conducted to investigate the effects of different feeding level of TDN (Total Digestible Nutrients) on the generation of main greenhouse gases such as carbon dioxide and methane in Hanwoo cows. The diet TDN (kg) adjusted to achieve ADG of 0 g/day (Control), 200 g/day (T1), and 400 g/day (T2) of the maintenance level TMR (Total Mixed Ration) delivered twice a day at 08:30 and 17:30. Cow are housed in a respiration chamber and the environmental temperature was maintained at $20^{\circ}C$. The gases were measured for 24 hours using the multi-detector instrument Mamos-300. The analyzed methane emissions of T1 and T2 were 33.5% and 69.6% higher than control, respectively, and the carbon dioxide emissions were 21.1% and 40.6% higher than control. Also, the hourly pattern of carbon dioxide and methane production were showed very similar emission. Gas production showed peak after 1 hour of feeding and this gap was wider in the afternoon than in the morning hours. It is clearly conducted that $CO_2$ and $CH_4$ emissions were different by limited intake levels of feed.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.242-252
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• 2016

A process-based ecosystem model, BIOME-BGC, was applied to simulate seasonal and inter-annual dynamics of carbon and water processes for potential evergreen needleleaf forest (ENF) biome in Korea. Two simulation sites, Milyang and Unljin, were selected to reflect warm-and-dry and cool-and-wet climate regimes, where massive diebacks of pines including Pinus densiflora, P. koraiensis and P thunbergii, were observed in 2009 and 2014, respectively. Standard Precipitation Index (SPI) showed periodic drought occurrence at every 5 years or so for both sites. Since mid-2000s, droughts occurred with hotter climate condition. Among many model variables, Cpool (i.e., a temporary carbon pool reserving photosynthetic compounds before allocations for new tissue production) was identified as a useful proxy variable of tree carbon starvation caused by reduction of gross primary production (GPP) and/or increase of maintenance respiration (Rm). Temporal Cpool variation agreed well with timings of pine tree diebacks for both sites. Though water stress was important, winter- and spring-time warmer temperature also played critical roles in reduction of Cpool, especially for the cool-and-wet Uljin. Shallow soil depth intensified the drought effect, which was, however, marginal for soil depth shallower than 0.5 m. Our modeling analysis implicates seasonal drought and warmer climate can intensify vulnerability of ENF dieback in Korea, especially for shallower soils, in which multi-year continued stress is of concern more than short-term episodic stress.

• Korean Journal of Environmental Agriculture
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• v.39 no.4
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• pp.334-342
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• 2020

BACKGROUND: To quantify carbon exchange at agricultural ecosystems in South Korea, net ecosystem exchange (NEE) at three croplands including a rice paddy, a bean field and an apple orchard was measured on the basis of the eddy covariance technique. METHODS AND RESULTS: NEE of CO2 during the growing season (June to September) averaged over the recent two years (2018-2019) was the highest at rice (-4.49 g C m-2 day-1), followed by the bean (-3.12 g C m-2 day-1) and apple (-0.93 g C m-2 day-1). The diurnal variation of NEE was the highest at the rice, while the seasonal variation of it was the highest at the bean than others. In terms of yearly variation, the rice paddy and the bean field absorbed more CO2 in 2019 compared to 2018, while the apple orchard absorbed less. CONCLUSION: Our results confirmed that these croplands consistently acted as net sinks for CO2 during the growing season because an amount of CO2 uptake from photosynthesis was larger than one of its emissions from respiration. The quantification of net CO2 exchange at agricultural ecosystems may help to better understand the local carbon cycle over various time scales.

• Journal of Science Education
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• v.45 no.3
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• pp.275-291
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• 2021

The purpose of this study is to analyze the level and characteristics of system thinking of middle and high school students on cycle of matter in the Earth system considering the impact of human activities on the cycle. For this purpose, we developed items for assessment and assessment rubric through the analysis of 2015 revised curriculum and applying systems thinking, respectively. Middle and high school students who participated in the Korea Earth Science Olympiad were the subjects of this study. The level of system thinking was determined using the assessment rubric for student responses collected using items for assessment. The characteristics of system thinking were identified using word analysis. Based on these, the improvement of the curriculum considering the impact of human activities was discussed. The results of the study are as follows: first, the system thinking level of most secondary school students was low in identifying or classifying system elements for matter cycle, and high levels, such as system relationship or generalization of patterns, were found to be relatively small. It was found that students had a higher level of system thinking in the carbon cycle than in the water cycle. Second, in terms of the characteristics of system thinking about water cycle, water was recognized as a major system element and mainly related with evaporation between atmosphere and other system elements. Whereas, in the carbon cycle, carbon dioxide was regarded as a major system element, and photosynthesis and respiration were represented in relation with the biosphere. Third, for education considering the impact of human activities on the matter cycle in the Earth system, it is proposed improving the curriculum considering the socio-ecological system by extending the existing earth system.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.675-686
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• 2015

Asparagus (Asparagus officinalis L.) needs proper post-harvest treatment to prolong its storage life. This study investigated the effect of 1-methylcyclopropene (1-MCP) on the quality and storage life of asparagus. Fresh-harvested asparagus was treated with 1-MCP ($1mg{\cdot}L^{-1}$), CEPA($10mg{\cdot}L^{-1}$), and 1-MCP($1mg{\cdot}L^{-1}$) + CEPA($10mg{\cdot}L^{-1}$) and compared with an untreated control. The carbon dioxide ($CO_2$) production, ethylene production, and morphological characteristics of the preserved asparagus were observed. The flow-system and the static-type measurement methods for ethylene and $CO_2$ production (respiration rate) were used. Weight loss, respiration rate, degree of freshness, and ethylene production were monitored during storage at $7^{\circ}C$. The results further showed that CEPA (2-chloroethylphosphonic acid) treatment had greater effects on $CO_2$ and ethylene production than using the 1-MCP process. The asparagus treated with CEPA or 1-MCP + CEPA had significantly increased the ethylene production rate compared to the control or using only 1-MCP during storage. There were no evident changes in the respiration rate of asparagus under 1-MCP treatment as compared with the control. Using the flow-system, slight differences in the rates of $CO_2$ and ethylene production were noted as compared to using the static type. Findings showed that in using the flow-system, asparagus manifested clearer results as compared with the static type. Weight loss in asparagus was significantly lower in control and 1-MCP treated samples than in those treated with CEPA. Likewise, the $CO_2$ and ethylene production of the CEPA treated samples significantly increased. The 1-MCP treatment reduced the effects of CEPA on weight loss, soluble solids content, and osmolality. The effect was not observed with exogenous ethylene as CEPA treatment had no visible effect as compared to the untreated group. Thus, 1-MCP treatment of asparagus could slightly reduce damage to the quality of asparagus during its distribution where ethylene gas is produced. Therefore, this study suggests that 1-MCP treatment can reduce the damage induced by ethylene gas on asparagus in poor distribution environments.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.2
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• pp.107-121
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• 2010

We conducted a sensitivity test of Joint UK Land Environment Simulator (JULES), in which the influence of biophysical parameters on the simulation of gross primary productivity (GPP) and ecosystem respiration (RE) was investigated for two typical ecosystems in Korea. For this test, we employed the whole-year observation of eddy-covariance fluxes measured in 2006 at two KoFlux sites: (1) a deciduous forest in complex terrain in Gwangneung and (2) a farmland with heterogeneous mosaic patches in Haenam. Our analysis showed that the simulated GPP was most sensitive to the maximum rate of RuBP carboxylation and leaf nitrogen concentration for both ecosystems. RE was sensitive to wood biomass parameter for the deciduous forest in Gwangneung. For the mixed farmland in Haenam, however, RE was most sensitive to the maximum rate of RuBP carboxylation and leaf nitrogen concentration like the simulated GPP. For both sites, the JULES model overestimated both GPP and RE when the default values of input parameters were adopted. Considering the fact that the leaf nitrogen concentration observed at the deciduous forest site was only about 60% of its default value, the significant portion of the model's overestimation can be attributed to such a discrepancy in the input parameters. Our finding demonstrates that the abovementioned key biophysical parameters of the two ecosystems should be evaluated carefully prior to any simulation and interpretation of ecosystem carbon exchange in Korea.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.2
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• pp.149-160
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• 2007

KoFlux Gwangneung Supersite comprises complex topography and diverse vegetation types (and structures), which necessitate complementary multi-disciplinary measurements to understand energy and matter exchange. Here, we report the results of this ongoing research with special focuses on carbon/water budgets in Gwangneung forest, implications of inter-dependency between water and carbon cycles, and the importance of hydrology in carbon cycling under monsoon climate. Comprehensive biometric and chamber measurements indicated the mean annual net ecosystem productivity (NEP) of this forest to be ${\sim}2.6\;t\;C\;ha^{-1}y^{-1}$. In conjunction with the tower flux measurement, the preliminary carbon budget suggests the Gwangneung forest to be an important sink for atmospheric $CO_2$. The catchment scale water budget indicated that $30\sim40%$ of annual precipitation was apportioned to evapotranspiration (ET). The growing season average of the water use efficiency (WUE), determined from leaf carbon isotope ratios of representative tree species, was about $12{\mu}mol\;CO_2/mmol\;H_2O$ with noticeable seasonal variations. Such information on ET and WUE can be used to constrain the catchment scale carbon uptake. Inter-annual variations in tree ring growth and soil respiration rates correlated with the magnitude and the pattern of precipitation during the growing season, which requires further investigation of the effect of a monsoon climate on the catchment carbon cycle. Additionally, we examine whether structural and functional units exist in this catchment by characterizing the spatial heterogeneity of the study site, which will provide the linkage between different spatial and temporal scale measurements.

• Journal of Bio-Environment Control
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• v.30 no.1
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• pp.77-84
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• 2021

This study attempted to find a way to maintain the quality of mixing baby wild leaf vegetables with existing baby leaf vegetables in various ratios. The crops for mixing baby leaf vegetables were Peucedanum japoincum Thunberg and Ligularia stenocephala, as wild vegetables, and red romaine, which is widely used in young leafy vegetables. The mixing ratio of red romaine and wild vegetables was red romaine 0: mantilla oil 5: L. stenocephala ratio 5 (R0: P5: L5), red romaine 3.3: P. japoincum 3.3: L. stenocephala ratio 3.3 (R3.3: P3.3: L3.3), red romaine 5: P. japoincum 2.5: L. stenocephala 2.5 (R5: P2.5: L2.5), red romaine 8: P. japoincum 1: L. stenocephala 1 (R8: P1: L1), red romaine 10: P. japoincum 0: L. stenocephala 0 (R10: P0: L0). All treatments were packaged in OTR (oxygen transmittance) 10,000 cc m-2·day-1·atm-1 film and stored for 27 days at 2℃/85% RH conditions. Fresh weight, carbon dioxide, oxygen, and ethylene concentrations of the baby leaf packages were examined approximately every 3 days, and visual quality, chlorophyll content, and chromaticity were examined on the 27th day of storage. The oxygen and carbon dioxide concentration in the packages were affected by the respiration rate of the crop. As the mixing ratio of lettuce, which had a low respiration rate, increased, the oxygen concentration in the packages was higher and the carbon dioxide concentration was lower. Oxygen concentration decreased significantly after 15 days, but was remained above 16%, and on the contrary, carbon dioxide concentration was kept at 1-4% until the 15th, and then gradually increased to 2-5% on the 27th day. The concentration of ethylene was maintained at 3-6 µL·L-1 until the end of storage (27th day). Visual quality score measured at the end of storage was slightly less than 3.0, which is the limit of marketability of all treatments. Although there was no significant difference, the chlorophyll content (SPAD) of red romaine and P. japoincum were most similar with an initial value in R8:P1:1 treatment, and L. stenocephala was higher value in R8:P1:L1 and R5:P2.5:L2.5 treatments at the end of storage. The leaf color (L∗, a∗, b∗, chroma) of the three crops at end of storage compared with the heat map showed the least change in the R5:P2.5:L2.5 and R8:P1:L1 treatments at the end of storage. Among them, R8:P1:L1 treatment maintained the highest chlorophyll content, the second lowest ethylene concentration, and adequate carbon dioxide concentration of 2-3%. Therefore, it is judged that the mixed ratio of red romaine 8: P. japoincum 1: L. stenocephala 1 (R8: P1: L1) is most suitable for the mixed package of baby leaf vegetables of these three crops.

• Journal of Animal Environmental Science
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• v.18 no.1
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• pp.19-24
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• 2012

The first objective of this study is to estimate emission coefficient of organic carbon regarding its inflow and discharge for dairy farm through reviewing domestic and foreign literature published or reported previously. Its second objective is to provide fundamental data to establish carbon cycle system related to livestock production. Based on literature review, emission coefficients by inflow of organic carbon into dairy farm were 5.9 ton C/head/year for feedstuff ingestion by milk cow, 2.3 ton C/head/year for recycling manure compost of milk cow to grassland, 318 g C/$m^2$/year for contents in grassland, 145 g C/$m^2$/year for contents in fodder crop, and 17 g C/$m^2$/year for $CO_2$ uptake by fodder crop, respectively. on the other hand, emission coefficients by discharge of organic carbon from dairy farm were 2,9 ton C/head/year for emission of $CO_2$ and $CH_4$ by respiration and burp of milk cow, 0.4 ton C/head/year for emission of $CO_2$ and $CH_4$ by decomposition of organic carbon in manure of milk cow, 440 g C/$m^2$/year for emission of $CO_2$ from grassland, and 0 for elution of organic carbon in grassland into underground water, respectively.