• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.13 no.4
• /
• pp.348-353
• /
• 2008

Oxygen isotope has not been used actively in water mass studies because of difficulties on the analysis though it has advantages as a water mass tracer. The most popular method to analysis the oxygen isotope ratio in water samples is equilibration method: isotopic equilibrium of water with $CO_2$ at constant temperature. The precision of oxygen isotope analysis using commercial automatic $H_2O/CO_2$ equilibrator is ${\pm}0.1%o$. This value is not sufficient for studies in open ocean. The object of this study is to improve the analytical precision enough to apply open ocean studies by modification of the instrument. When sample gas is transferred by the pressure difference, the fractionation which is preferential transportation of light isotope can be occurred since the long transportation path between the equilibrator and mass spectrometer. And the The biggest source of error during the analysis is long distance and large volume of the pathway of sample gas between. Therefore, liquid nitrogen trap and high vacuum system are introduced to the system. The precisions of 14 time analysis of same seawater sample are ${\pm}0.081%o$ and ${\pm}0.021%o$ by built-in system and by modified system in this study, respectively.

• Korean Journal of Ecology and Environment
• /
• v.57 no.1
• /
• pp.1-16
• /
• 2024

Most wetlands worldwide have suffered from extensive human exploitation. Unfortunately they have been less explored compared to river and lake ecosystems despite their ecological importance and economic values. This is the same case in Korea. This study was aimed to estimate the assemblage attributes and distribution characteristics of benthic macroinvertebrates for fifty wetlands distributed throughout subtropical Jeju Island in 2021. A total of 133 taxa were identified during survey periods belonging to 53 families, 19 orders, 5 classes and 3 phyla. Taxa richness ranged from 4 to 31 taxa per wetland with an average of 17.5 taxa. Taxa richness and abundance of predatory insect groups such as Odonata, Hemiptera and Coleoptera respectively accounted for 67.7% and 68.2% of the total. Among them Coleoptera were the most diverse and abundant. Taxa richness and abundance did not significantly differ from each wetland type classified in accordance with the National Wetland Classification System. There were three endangered species (Clithon retropictum, Lethocerus deyrolli and Cybister (Cybister) chinensis) and several restrictively distributed species only in Jeju Island. Cluster analysis based on the similarity in the benthic macroinvertebrate composition largely classified 50 wetlands into two major clusters: small wetlands located in lowland areas and medium-sized wetlands in middle mountainous regions. All cluster groups displayed significant differences in wetland area, long axis, percentage of fine particles and macrophyte composition ratio. Indicator Species Analysis selected 19 important indicators with the highest indicator value of Ceriagrion melanurum at 63%, followed by Noterus japonicus (59%) and Polypylis hemisphaerula (58%). Our results are expected to provide fundamental information on the biodiversity and habitat environments for benthic macroinvertebrates in wetland ecosystems, consequently helping to establish conservation and restoration plans for small wetlands relatively vulnerable to human disturbance.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.19 no.3
• /
• pp.27-40
• /
• 2024

This study empirically derives the factors affecting the practice of corporate social responsibility (CSR) of venture firms in Korea from the perspective of Slack Resource Theory and the company's growth strategy, and provides implications for future expansion of venture firm's CSR activities. In Korea, venture firms have grown into important players in the national economy since the late 1990s through social contributions such as economic value creation, job creation, and technological development. As venture companies grow in status, positive relationships with stakeholders and responsibility for environmental and social values are required. Now, CSR is becoming an important strategic choice for SMEs and venture firms. However, until now, CSR-related academic research has mainly focused on large or listed corporations, and there is not much research on SMEs or venture firms. In particular, research on the factors that lead venture companies to make important business decisions of participating in CSR activities is not there yet. This study applied logistic multiple regression analysis using the '2023 Survey on Venture Firms' conducted by the Ministry of SMEs and Startups. As a result of this study, operating profit, which is an available resources of venture companies, and government support, which is a potential resource, have a positive impact on venture firms's CSR activities. Also, business relationships with large corporations and expectation for future cooperation also have a positive impact on CSR activities as the determinants. On the other hand, it was analyzed that in venture firms where ownership and management are not separated, the higher the CEO's shareholding ratio, the more negatively it affects CSR activities. This study contributes academically as the first empirical study on the determinants of CSR activities of venture firms in Korea and provides implications that government policy support and collaboration between large corporations and venture firms are important in order to expand CSR activities of venture firms.

• Journal of Bio-Environment Control
• /
• v.32 no.4
• /
• pp.278-284
• /
• 2023

Recently, a closed-type plant factory has been receiving attention as a advanced agricultural method. It has diverse advantages such as climate-independence, high productivity and stable year-round production. However, high energy cost caused by environmental control system is considered as a challenges of a closed-type plant factory. In order to reduce the energy cost, investigation about energy load which is directly connected to energy consumption needs to be conducted. In this study, energy load changes of a plant factory have been analytically analyzed according to the environmental changes. The target plant factory was a lettuce growing container farm. Firstly, the impact of photoperiod, set temperature and relative humidity change were examined. Under the climate condition of Daejeon in South Korea, increase of photoperiod and set temperature rose a yearly energy demand of a container farm. However, increase of set relative humidity decreased a yearly energy demand. Secondly, the climate environment effect was compared by investigating the energy demand under 9 different climate conditions. As a result, the difference between maximum and minimum value of the yearly energy demand showed 21.7%. Lastly, sensitivity analysis of each parameter (photoperiod, set temperature and relative humidity) has been suggested under 3 different climate conditions. The ratio of heating and cooling demand was varied depending on the climate, so the effect of each parameter became different.

• Journal of Bio-Environment Control
• /
• v.32 no.4
• /
• pp.475-483
• /
• 2023

This study was conducted to determine the optimal irrigation starting point by analyzing tree growth, physiological responses, fruit quality, and productivity in peach orchards. Seven-year-old 'Kawanakajima Hakuto' peach trees were used in an experimental field (35°49'30.4"N, 127°01'33.2"E) located within the National Institute of Horticultural and Herbal Science located in Wanju-gun, Jeollabuk-do. The irrigation starting point was set with four levels of -20, -40, -60, and -80 kPa from June to September 2022. While there were no significant differences in increase of trunk cross-section area and leaf area among treatments, shoot length and diameter decreased in the -80 kPa and -20 kPa treatments. The photosynthetic rate measured in August was highest for -60 kPa (17.7 μmol·m^-2·s^-1), followed by -40 kPa (15.6 μmol·m^-2·s^-1), -20 kPa (14.5 μmol·m^-2·s^-1) and -80 kPa (14.0 μmol·m^-2·s^-1). SPAD value measured in May and August was lower in the -80 kPa and -20 kPa treatments than in the -60 kPa and -40 kPa treatments. The harvest date reached three days earlier in the -20 kPa treatment compared to other treatments. The fruit weight was highest in the -60 kPa (379.1 g), followed by -40 kPa (344.0 g), -80 kPa (321.0 g) and -20 kPa (274.9 g). Firmness was the lowest in the -20 kPa treatment. The soluble solid content was highest in the -60 kPa treatment (13.3°Bx).The ratio of marketable fruits was highest in the -60 kPa treatment (50.7%) and lowest in the -80 kPa treatment (23.4%). In conclusion, we suggest that setting the irrigation starting point at -60 kPa could improve the fruit quality and yield in peach orchards.

• Journal of Bio-Environment Control
• /
• v.33 no.1
• /
• pp.12-21
• /
• 2024

The aim of this research was to investigate the effect of gibberellin on improving seedling growth characteristics and enhancing strawberry quality in cutting propagation. Cuttings of the cultivar 'Seolhyang' were treated with GA₃ for 30 and 60 minutes at concentrations of 50, 100, and 150 mg·L^-1, with distilled water used for dipping as the control. Evaluation of seedling growth showed a positive correlation between the duration of gibberellin dipping and growth characteristics such as leaf number and SPAD value. Plant height, petiole length, leaf length and width, and leaf area varied significantly based on the interaction between dipping time and concentration. Crown diameter exhibited differences depending on the dipping time, with cuttings producing superior seedlings having a diameter of 8.0 mm or more for all treatments except the 30-minute, 100 mg·L^-1 treatment. The T/R ratio was significantly lower in the 30-minute, 50 mg·L^-1 treatment, indicating the highest plant vigor. Quantum yield was lower at a concentration of 150 mg·L^-1, showing a decreasing trend with increasing gibberellin concentration. Nonphotochemical quenching was significantly smaller in the 30-minute, 150 mg·L^-1 treatment, indicating an effective reduction of stress in the cuttings. Antioxidant content was highest in the 30-minute, 50 mg·L^-1 treatment and the 60-minute, 150 mg·L^-1 treatment. Moreover, the results of post-transplanting growth assessment showed no negative effect of gibberellin on flowering induction. Therefore, it was confirmed that gibberellin treatment during the cutting propagation of 'Seolhyang' strawberries had a positive effect on the production of high-quality seedlings. Dipping the cuttings in 50 mg·L^-1 gibberellin for 30 minutes is considered to be the most suitable method for improving growth and quality compared to the control.

• Journal of Bio-Environment Control
• /
• v.33 no.2
• /
• pp.79-87
• /
• 2024

This study confirmed the effects of seed shape, temperature, and light treatment on the germination of eight species of medicinal crops to produce high-value crops in vertical farms. Eight species of medicinal seeds were selected, and the seed shape, seed length, seed width, seed length/width ratio, and one hundred seed weight were measured. The seed moisture content was confirmed. Eight species of medicinal seeds were sown, and the germination rate, germination energy, mean daily germination, and mean germination time were investigated according to temperature (15, 20, 25, 25/15℃) and light treatment. Each of the eight medicinal seeds showed different seed shapes. The moisture content of the seeds showed a moisture content rate of over 20% in the five medicinal seeds. Medicinal seeds that showed a germination rate of over 50% were Angelica gigas Nakai, Codonopsis lanceolata (Siebold & Zucc.) Benth. & Hook.f. ex Trautv., and Achyranthes bidentata Blume var. japonica Miq. seeds. A. gigas seed showed a germination rate of 67.34 ± 4.38% under 25/15℃ light conditions, and C. lanceolata seed showed a germination rate of over 50% under both temperature and light treatment conditions, especially the highest germination rate of 82.67 ± 1.46% under 15℃ dark conditions. Peucedanum japonicum Thunb. seed showed a germination rate of 52.34 ± 1.77% under dark conditions at 20℃, and the highest germination rate was 51.67 ± 3.79% under dark conditions at 15℃. The maximum germination energy was 74.00 ± 4.94% in C. lanceolata seed. The maximum mean daily germination was 14.94 ± 0.15 days in P. japonicum seed. Astragalus penduliflorus Lam. var. dahuricus (DC.) X.Y.Zhu seed showed the highest mean germination time of 34.19 ± 4.71. Through this study, it was determined that A. gigas, C. lanceolata, and A. penduliflours seeds would be suitable for production in vertical farms based on the characteristics of each medicinal seed through analysis of seed germination characteristics.

• Korean Journal of Soil Science and Fertilizer
• /
• v.21 no.4
• /
• pp.386-408
• /
• 1988

A study was conducted to develop a model for estimating evapotranspiration and yield of Chinese cabbages from meteorological factors from 1981 to 1986 in Suweon, Korea. Lysimeters with water table maintained at 50cm depth were used to measure the potential evapotranspiration and the maximum evapotranspiration in situ. The actual evapotranspiration and the yield were measured in the field plots irrigated with different soil moisture regimes of -0.2, -0.5, and -1.0 bars, respectively. The soil water content throughout the profile was monitored by a neutron moisture depth gauge and the soil water potentials were measured using gypsum block and tensiometer. The fresh weight of Chinese cabbages at harvest was measured as yield. The data collected in situ were analyzed to obtain parameters related to modeling. The results were summarized as followings: 1. The 5-year mean of potential evapotranspiration (PET) gradually increased from 2.38 mm/day in early April to 3.98 mm/day in mid-June, and thereafter, decreased to 1.06 mm/day in mid-November. The estimated PET by Penman, Radiation or Blanney-Criddle methods were overestimated in comparison with the measured PET, while those by Pan-evaporation method were underestimated. The correlation between the estimated and the measured PET, however, showed high significance except for July and August by Blanney-Criddle method, which implied that the coefficients should be adjusted to the Korean conditions. 2. The meteorological factors which showed hgih correlation with the measured PET were temperature, vapour pressure deficit, sunshine hours, solar radiation and pan-evaporation. Several multiple regression equations using meteorological factors were formulated to estimate PET. The equation with pan-evaporation (Eo) was the simplest but highly accurate. PET = 0.712 + 0.705Eo 3. The crop coefficient of Chinese cabbages (Kc), the ratio of the maximum evapotranspiration (ETm) to PET, ranged from 0.5 to 0.7 at early growth stage and from 0.9 to 1.2 at mid and late growth stages. The regression equation with respect to the growth progress degree (G), ranging from 0.0 at transplanting day to 1.0 at the harvesting day, were: $$Kc=0.598+0.959G-0.501G^2$$ for spring cabbages $$Kc=0.402+1.887G-1.432G^2$$ for autumn cabbages 4. The soil factor (Kf), the ratio of the actual evapotranspiration to the maximum evapotranspiration, showed 1.0 when the available soil water fraction (f) was higher than a threshold value (fp) and decreased linearly with decreasing f below fp. The relationships were: Kf=1.0 for $$f{\geq}fp$$ Kf=a+bf for f$$I{\leq}Esm$$ Es = Esm for I > Esm 6. The model for estimating actual evapotranspiration (ETa) was based on the water balance neglecting capillary rise as: ETa=PET. Kc. Kf+Es 7. The model for estimating relative yield (Y/Ym) was selected among the regression equations with the measured ETa as: Y/Ym=a+bln(ETa) The coefficients and b were 0.07 and 0.73 for spring Chinese cabbages and 0.37 and 0.66 for autumn Chinese cabbages, respectively. 8. The estimated ETa and Y/Ym were compared with the measured values to verify the model established above. The estimated ETa showed disparities within 0.29mm/day for spring Chinese cabbages and 0.19mm/day for autumn Chinese cabbages. The average deviation of the estimated relative yield were 0.14 and 0.09, respectively. 9. The deviations between the estimated values by the model and the actual values obtained from three cropping field experiments after the completion of the model calibration were within reasonable confidence range. Therefore, this model was validated to be used in practical purpose.

• Journal of Gastric Cancer
• /
• v.6 no.1
• /
• pp.36-42
• /
• 2006

Purpose: The $p21^{Waf1/Cip1}$ protein Inhibits the cell cycle by Inhibiting the phosphorylation at the $G1{\rightarrow}S$ check point, and the $p27^{kip1}$ protein similarly performs the suppressor function by controlling the p27-mediated G1 arrest. In this study, we analysed the clinical status and survival rates in correlations with p21 and p27 expression patterns in gastric cancer. Materials and Methods: Between 1993 and 1997, 192 patients who underwent surgeries in Catholic Medical Center were analysed retrospectively in this study. Immunohistochemical staining was performed and if the nuclei of the tumor cells were stained, we assumed those as positive results. Statistical analysis was based on clinicopathological findings and differences in survival rates. Results: The expression rate of p27 was 28.1% and 15.6% in p21 each. The ratio of T1-2(80.0%) was significantly high in p21 (+), but the ratio of T3-4 (50.6%) was slightly high in p21 (-). There was no statistical significance regarding other factors. The results in p27 was not much different from expression rate of p21 in T-stage. In addition, p27 expression in diffuse type (91.3%) was higher than in intestinal type (62.7%) by Lauren's classification (P<0.05). Also, there was no statistical significance in other factors. In the correlation of p21 and p27, p27 was positive when p21 was positive (53.5%). Conversely, p27 was negative when p21 was negative (76.5%, p<0.05). In the p21 and p27 combination test, there was higher rate of T1-2 (87.5%) in p21 (+)/p27 (+), and higher rate of T3-4 (58.1%) in p21 (-)/p27 (-) (P<0.05). Results showed higher rate of intestinal type (100%) in p21 (+)/p27 (+), and diffuse type (87.0%) was dominant in p21 (-)/p27 (-) (P<0.05) by Lauren's classification. Moreover, there was no statistical significance in the 5-year survival rate in the expression of p21 and p27, and the 5-year survival rate was highest in the case of p21 (+)/p27 (+) without statistical significance. Conclusion: In our study, $p21^{Waf1/Cip1}\;and\;p27^{kip1}$ expressed similar patterns. The expression of $p21^{Waf1/Cip1}\;and\;p27^{kip1}$ affected the degree of invasiveness of the tumor, and. Combined examination result revealed the correlation of $p21^{Waf1/Cip1}\;and\;p27^{kip1}$ with Lauren's classification and depth of invasion of the tumor. However, we assumed that little difference between the survival rates depending on expression of $p21^{Waf1/Cip1}\;and\;p27^{kip1}$ has limited their value as predictable prognostic indicators.

• Journal of Korean Society of Forest Science
• /
• v.80 no.1
• /
• pp.72-81
• /
• 1991

This study was carried out to provide necessary information for improving quarrying industry management in Korea. The results of the study are summarized as follows : 1. In aggregate and building-stone quarrying firms the managers over 40 years of age are 97% and 89.1%, the ones above education level of high school are 90% and 85% and the ones not more than 10 years of quarrying experience are 70% and 52%, respectively. Accordingly it can be pointed out that most of the managers of two types of firms are relatively old, have high educational background, while quarrying experiences of building-stone firm managers are longer than that of aggregate firm managers. 2. Most of the management forms are social corporation(60%) for aggregate quarry firms and private management(76%) for building-stone firms. Average areas of permitted stone-pits of aggregate and building-stone quarries are about 2.86ha and 1.66ha respectively. That is, aggregate quarrying firms are carried on a larger scale than building-stone quarrying firms. 3. The yearly average product of aggregate quarrying firms has increased steadily from $88.961m^3$ in 1985 to $144.028m^3$ in 1988, while, in case of building-stone quarry firms, it has significantly increased from $4.155m^3$ to $19.462m^3$ from 1985 to 1987, but reduced to $13.400m^3$ in 1988. Unstable production activities of building-stone quarrying firms may require continuous government support. 4. Major cost items are equipment rental, depreciation, salaries, repair, maintenance for aggregate quarrying firms, and salaries, depreciation, fuel, tax for building-stone quarrying firms. The yearly average rate of return is about 9.7% for aggregate quarry firms and 2.6% for building-stone quarry firms. It can be pointed out that aggregate quarrying firms is better managed than building-stone quarrying firms. 5. The production elasticity of salary for aggregate quarrying firms is 0.495, that of employees is 0.559, and that of capital service is 0.513. The sum of the elasticities is 1.257>1. Fur building-stone quarrying firms, that of employees is 0.492, that of variable costs is 0.192, and that of capital service is 0.498. The sum of elasticities is 1.172>1, thus denotes the increasing returns to scale for both types quarrying firms. 6. The ratio of marginal value product to opportunity cost of empolyees is 2.54, that of variable costs is 3.62, and that of capital service is 1.45, in aggregate quarrying firms. That of employees is 2.47, that is variable costs was 2.34, and that of capital service is 19.67 in building-stone quarrying firms. Therefore the critical factors for more expansion of management scale in aggregate quarrying firms are variable cost and employees, and are capital service in building-stone quarry ing firms. 7. The break-even points of stone sales are about 0.587 billion won and 0.22 billion won in aggregate and building-stone quarrying firms respectively. The optimum sales Level for profit maximization are about 2.0 billion and 0.5 billion in aggregate and building-stone quarry firms respectively.