• Journal of Mushroom
• /
• v.21 no.4
• /
• pp.254-260
• /
• 2023

The characteristics and spore production of Gonji7ho, Bunhong, and Sunjung fruiting bodies were assessed at different growth stages. The shape of the Pleurotus species fruiting body starts out short and small, then takes on a typical mushroom shape as it grows. Gonji7ho has a long stalk, Bunhong has a short stalk and a wide cap, and Sunjung's cap and stalk dimensions are intermediate. Each variety displayed deep color at the beginning of growth but became steadily lighter with continued growth. The shape of the linkage between the mushroom stalk and cap changed from an initial central position to a lateral position after the growing stage. Gonji7ho cap diameter increased 7-fold from 15.5 mm (5 days of growth) to 37.9 mm (9 days of growth). Growth rates for each growth day measured using the growth percentage of the previous day were 285.5% (5 → 6th day), 182.2% (6 → 7th day), 129.4% (7 → 8th day), and 103.8% (8 → 9th day). This trend was also observed in Bunhong and Sunjung, but Bunhong's growth rate was more rapid (4.9 fold on day 6, 2.7 fold on day 7) and continued to increase through day 9. Harvest yield, which is of greatest interest to farmers, displayed a similar trend spanning the growth period, as did cap diameter. Gonji7ho harvest yield increased rapidly until day 7 of growth (more than 177%), then growth slowed down beginning around day 8, and further decreased on day 9 (98%). Similar trends were observed in Bunhong and Sunjung. Bunhong showed characteristic rapid growth in harvest yield (4.9 fold compared to the previous day on day 6 and 2.7 fold on day 7), and the increase continued through day 9. A decrease in mushroom harvest yield commonly seen in the late growth stage is thought to be due to the death of some mushrooms and decomposition of cap tissue. Basidiospore content increased with number of growth days but decreased after day 8. Gonji7ho yielded the highest production on day 7 of growth, coinciding with harvest time, with 209,000,000 spores. This trend was also observed in Bunhong and Sunjung. These results will provide researchers with basal data and guide farmers in selecting the optimal harvest day.

• Journal of Korea Water Resources Association
• /
• v.56 no.12
• /
• pp.993-1003
• /
• 2023

Due to the increasing greenhouse gas emissions, the global mean temperature has risen by 1.1℃ compared to pre-industrial levels, and significant changes are expected in functioning of water supply systems. In this study, we assessed impacts of climate change and instreamflow management on water supply reliability in the Geum River basin, Korea. We proposed univariate climate response functions, where mean precipitation and potential evaporation were coupled as an explanatory variable, to assess impacts of climate stress on multiple water supply reliabilities. To this end, natural streamflows were generated in the 19 sub-basins with the conceptual GR6J model. Then, the simulated streamflows were input into the Water Evaluation And Planning (WEAP) model. The dynamic optimization by WEAP allowed us to assess water supply reliability against the 2020 water demand projections. Results showed that when minimizing the water shortage of the entire river basin under the 1991-2020 climate, water supply reliability was lowest in the Bocheongcheon among the sub-basins. In a scenario where the priority of instreamflow maintenance is adjusted to be the same as municipal and industrial water use, water supply reliability in the Bocheongcheon, Chogang, and Nonsancheon sub-basins significantly decreased. The stress tests with 325 sets of climate perturbations showed that water supply reliability in the three sub-basins considerably decreased under all the climate stresses, while the sub-basins connected to large infrastructures did not change significantly. When using the 2021-2050 climate projections with the stress test results, water supply reliability in the Geum River basin was expected to generally improve, but if the priority of instreamflow maintenance is increased, water shortage is expected to worsen in geographically isolated sub-basins. Here, we suggest that the climate response function can be established by a single explanatory variable to assess climate change impacts of many sub-basin's performance simultaneously.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.18 no.4
• /
• pp.131-148
• /
• 2023

The purpose of this study is to investigate the effects of entrepreneurial environment and entrepreneurial competency on entrepreneurial intention by setting degree of self-determination as a moderating variable for pre-entrepreneur of agriculture industry. The entrepreneurial environment was divided into perceived support and perceived barriers, and the sub-variables of entrepreneurial competence were set as creativity, problem solving, communication, marketing, and business plan. 253 questionnaires were used for empirical analysis. The results of the analysis using SPSS v25.0 and Process macro v4.2 are as follows. First, the perceived support and perceived barriers of the entrepreneurial environment have a significant effect on entrepreneurial intention. Creativity, problem solving, marketing and business plan of entrepreneurial competency have a significant effect on entrepreneurial intention, but the effect of communication was non-significant. Second, the degree of self-determination did not moderate the relationship between perceived support, barriers and entrepreneurial intention. This means that the level of self-determination may not have a significant effect on the relationship between entrepreneurial environment and entrepreneurial intention. Third, the degree of self-determination was found to moderate the relationship between creativity, problem solving, communication, marketing and business plan of entrepreneurial competency and entrepreneurial intention. Specifically, as the degree of self-determination increases, the size of the influence of creativity, problem solving, marketing, and business plan on entrepreneurial intention plays a role of strengthening in a positive direction. On the other hand, as the degree of self-determination increases, the degree of self-determination, which weakens the relationship between communication and entrepreneurial intention. Future research will require exploration of other factors that can explain entrepreneurial environment and entrepreneurial capacity, and follow-up studies are needed to analyze the moderated mediating effects through conditional process models that include new mediating and moderating variables.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.17 no.4
• /
• pp.87-100
• /
• 2022

Early start-up companies have an inherent limitation of lack of resources. Despite these limitations, in order to survive, the entrepreneur's personal ability to efficiently use limited resources is required. In the marketing field, various studies are needed to reduce the business failure rate through establishing growth strategies and innovation. Accordingly, it is necessary to apply the concept of entrepreneurial marketing, which has been researched and developed overseas for 30 years, to fit the domestic reality. According to the flow of this study, an empirical study should be preceded to clarify the influence relationship between entrepreneurial marketing orientation, marketing competency, and management performance, along with a theoretical theorem on entrepreneurial marketing that is suitable for early start-ups and small and medium-sized enterprises(SMEs) and can respond innovatively to changes. The establishment of entrepreneurial marketing orientation and the processes from which this concept leads to business performance through the organization's marketing capabilities and its effects will be empirically verified. For an empirical survey, a survey was conducted on founders of 220 companies, and path analysis using structural equations was used for hypothesis verification. The findings are as follows. First, it was found that the entrepreneurial marketing orientation had a positive effect on both the organization's marketing capabilities and management performance. Second, it was found that the organization's marketing capabilities also had a positive effect on management performance. Third, as a result of empirical analysis of the mediating effect of the organization's marketing capabilities on the relationship between entrepreneurial marketing orientation and management performance, it was found that marketing capabilities showed a greater mediating effect on non-financial performance than financial performance. On the other hand, it was confirmed that marketing performance had a stronger mediating effect on financial performance than non-financial performance. By confirming and presenting the concept and constituent factors of entrepreneurial marketing orientation of domestic start-ups, which were academic gaps for the purpose of this paper, the academic research is differentiated in that they were verified as six components of entrepreneurial marketing. The practical implications of the research results will be that the entrepreneurial marketing-oriented mindset of small and medium-sized companies will optimize market analysis capabilities, network with various stakeholders, and increase the organization's ability to demonstrate marketing capabilities.

• Pediatric Infection and Vaccine
• /
• v.31 no.1
• /
• pp.113-121
• /
• 2024

Purpose: In response to the surge in coronavirus disease 2019 (COVID-19) omicron variant cases, we have implemented preemptive testing for preschool and school. The purpose is to quickly detect COVID-19 cases using a rapid antigen test (RAT) kit so that normal school activities can continue. Methods: The results entered in The Healthcare Self-Test App were merged with the information on the status of confirmed cases in the COVID-19 Information Management System by Korea Disease Control and Prevention Agency (KDCA) for preschool and school of students and staffs March 2 to May 1, 2022 to analyze the RAT positive rate and positive predictive value of RAT. Results: In preschool and school 19,458,575 people were tested, weekly RAT positive rate ranged from 1.10% to 5.90%, positive predictive value of RAT ranged from 86.42% to 93.18%. By status, RAT positive rate ranged from 1.13% to 6.16% for students, 0.99% to 3.93% for staffs, positive predictive value of RAT ranged from 87.19% to 94.03% for students, 77.55% to 83.10% for staffs. RAT positive rate by symptoms ranged from 76.32% to 88.02% for those with symptoms and 0.34% to 1.11% for those without symptoms. As a result of preschool and school RAT, 943,342 confirmed cases were preemptively detected, before infection spread in preschool and school. Conclusions: RAT was well utilized to detect confirmed cases at an early stage, reducing the risk of transmission to minimize the educational gap in preschool and school. To compensate for the limitations of RAT, further research should continue to reevaluate the performance of RAT as new strains of viruses continue to emerge. We will have to come up with various ways to utilize it, such as performing periodic and repeated RAT and parallel polymerase chain reaction.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.14 no.4
• /
• pp.195-204
• /
• 2009

In order to estimate sea surface current fields in the East Sea, we examined characteristics of mean dynamic topography (MDT) fields (or mean surface current field, MSC) generated from three different methods. This preliminary investigation evaluates the accuracy of surface currents estimated from satellite-derived sea level anomaly (SLA) data and three MDT fields in the East Sea. AVISO (Archiving, Validation and Interpretation of Satellite Oceanographic data) provides a MDT field derived from satellite observation and numerical models with $0.25^{\circ}$ horizontal resolution. Steric height field relative to 500 dbar from temperature and salinity profiles in the East Sea supplies another MDT field. Trajectory data of surface drifters (ARGOS) in the East Sea for 14 years provide another MSC field. Absolute dynamic topography (ADT) field is calculated by adding SLA to each MDT. Application of geostrophic equation to three different ADT fields yields three surface geostrophic current fields. Comparisons were made between the estimated surface currents from the three different methods and in-situ current measurements from a ship-mounted ADCP (Acoustic Doppler Current Profiler) in the southwestern East Sea in 2005. For offshore areas more than 50 km away from the land, the correlation coefficients (R) between the estimated versus the measured currents range from 0.58 to 0.73, with 17.1 to $21.7\;cm\;s^{-1}$ root mean square deviation (RMSD). For coastal ocean within 50 km from the land, however, R ranges from 0.06 to 0.46 and RMSD ranges from 15.5 to $28.0\;cm\;s^{-1}$. Results from this study reveal that a new approach in producing MDT and SLA is required to improve the accuracy of surface current estimations for the shallow costal zones of the East Sea.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.13 no.3
• /
• pp.210-221
• /
• 2008

The mesoscale environmental surveys were conducted between $5^{\circ}N\;and\;17^{\circ}N$ mainly along the $131.5^{\circ}W$ meridian from 1997 to 2002 to investigate controlling factors of carbon and nitrogen contents in bottom sediments. Sediments of the study area showed zonal distribution pattern depending on latitudinal position and can be classified into four types; calcareous ooze($5{\sim}6^{\circ}N$), siliceous sediments($8{\sim}12^{\circ}N$), pelagic red clay($16{\sim}17^{\circ}N$), and mixed sediments($7^{\circ}N$). Inorganic carbon(IC) contents varied depending on water depth and carbonate compensation depth(CCD). Carbonate materials were well preserved in the low latitude region, where water depths are shallower than CCD. In contrast, the higher latitude region dominated by siliceous sediment and pelagic red clays has low productivity in water column as well as the water depths deeper than CCD. Thus, most of carbonate materials were dissolved, which resulted in IC contents of less than 0.05% in the sediments. Organic carbon(OC) and total nitrogen contents(TN) in siliceous sediments were higher than in pelagic red clay sediments simply because of higher primary productivity in the siliceous sediment dominated area. The contents of OC and TN were lower in the calcareous ooze than in the siliceous sediments. It is attributed to the high input of calcareous material to the bottom due to relatively shallow water depth of the area, which diluted organic matter contents in the sediment. Overall results indicated that water depth relative to CCD, primary production in water column, and sedimentation rate largely controls the large-scale distribution of carbon and nitrogen contents in the study area.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.14 no.4
• /
• pp.213-228
• /
• 2009

This study was conducted to investigate spatio-temporal changes in macrobenthic community structure and benthic environmental conditions in Geoje-Hansa Bay, which is the greatest oyster producing site in Korea. Field survey for benthic environment and macrobenthos was seasonally carried out at 15 stations covering oyster farming sites and non-farming sites from February to November, 2008. The grain size of surface sediments was dominated by very fine silt with the mean phi of about $9\;{\Phi}$ and TOC was 1.9% on average. Mean dissolved oxygen content was 8.1 mg/L and lowest in August corresponding to the 2nd degree in seawater quality criteria. Total species number was 351 and mean density was $3,675\;ind./m^2$, both of which were dominated by polychaete worms. Spatio-temporal variation in above two biological variables was great with higher values seasonally in spring and spatially in channels rather than inner bay. Dominant species were Lumbrineris longifolia (21.3%), Aphelochaeta monilaris (17.8%) and Ericthonius pugnax(6.1%), all of which are typical species of organically enriched area. From the multivariate analyses, the whole macrobenthic community was distinguished into two groups of channel and inner bay group. Spatio-temporal changes of macrobenthic community in Geoje-Hansan Bay were related to those of TOC and acid volatile sulfide (AVS). Our results showed that Geoje-Hansan Bay should be intermediately affected by organic pollution, and that such organic enrichment was more remarkable at farming stations in the inner bay.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.12 no.3
• /
• pp.191-199
• /
• 2007

Seasonal variation in species composition of fish in the Saemangeum Reservoir was determined using seasonal samples collected by an otter trawl from April 2006 to February 2007 after the dike construction, and compared with the data obtained during the dike construction in 2001-2002. A total of 35 species, 8,960 individuals and 53,084.4 g of fish were collected during the study. Of the fish collected, brackish and coastal fishes such as Konosirus punctatus, Synechogobius hasta and Repomucenus lunatus, and migrant fishes such as Engraulis japonicus and Scomberomorus niphonius predominated in abundance accounting for 95% in the total number of individuals. Fish species composition and abundance showed a similar seasonal trend to those in the other western coastal waters of Korea. The resident species were mainly collected in spring and in autumn. The number of species and biomass were high in summer by the large amount of catch of migrating species. Catch was low in winter and only 2 species were collected. A brackish and coastal fish, K. punctatus and two migrant fishes, E. japonicus and S. niphonius were abundantly collected after the dike construction. However, the dominant fishes during the dike construction such as Leiognathus nuchalis, Neosalanx jordani and Chaeturichthys stigmatias were rarely collected. Fish density was $1,149\;inds./10,000m^2\;and\;12,644g/10,000m^2$ during the dike construction, and increased 6 times in the number of individuals ($7,467\;inds./10,000m^2$) and 3 times in biomass ($44,237g/10,000m^2$) after the dike construction. Annual species richness (R) and species diversity (H') decreased from R=0.0160 and H'=2.47 during the dike construction in 2001-2002 to R=0.0038 and H'=1.11 after dike construction in 2006-2006, respectively. These changes seemed to be related to the reduction of the saline area and degradation of water quality in Semangeum Reservoir after the dike construction.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.12 no.3
• /
• pp.159-169
• /
• 2007

Excessive input of organic matters from fish cage farms to the coastal waters has been considered as one of the major factors disturbing their benthic ecosystem. Sediment samples were taken from around the two fish cage zones (A and B) in Tongyeong coast in June and August 2003, to evaluate the ecological impacts of fish cage farming activity on the macrobenthic polychaete communities. Polychaete accounted for $81{\sim}87%$ of the total macrofauna individuals from each of the sampling stations. The number of species, abundance, diversity and dominant species of polychaete were rapidly changed with the distance from the fish cages. Within 10 m from the fish cages, Capitella capitata, which is a bio-indicator for the highly enriched sediments, was a dominant species and the lowest diversity was recorded. In particular, the maximum density (${\sim}18,410\;ind.m^2$) of C. capitata was found at Farm A where fish cages were more densely established within a semi-enclosed bay system. The sampling zone between 10 m and 15 m showed a rapid decrease of C. capitata with a rapid increase of the numbers of species, implying that this zone may be an ecotone point from a highly to a slightly enriched area. In the sampling zone between 15 m and 60 m, a transitional zone, which represents slightly enriched condition before normal one, was observed with additional increase and maintenance of the number of species and density of polychaete. In addition, the potential bio-indicators of organic enrichment, such as Lumbrineris longifolia and Aphelochaeta monilaris were the predominant species in the sampling zone. Multidimensional scaling (MDS) ordination plots and k-dominance curves confirmed the above results on the gradual changes in the macrobenthic polychaete communities. Our findings suggest that the magnitude of impact of fish cage farming activity on polychaete communities is probably governed by a distance from fish cage, density of fish cage and geomorphological characteristics around fish cage farm.