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A Study on the Formation of River Sandbar and Management of River Forestation & Aggradation - Focusing on the Jang-Hang Wetland on the Han River - (하천의 사주 형성과 하도 수림화 및 육역화 관리방안에 관한 연구 - 한강 장항습지를 중심으로 -)

  • Hong Kyu Ahn;Dong Jin Lee
    • Ecology and Resilient Infrastructure
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    • v.11 no.2
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    • pp.43-54
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    • 2024
  • Recently, most of the rivers in Korea are experiencing various problems in dimension and river environment, such as expansion of stable area where disturbance does not occur during flood, increase of excessive trees in river channel, fixation of river channel, reduction of sand bar. When the soil supplied by the flood is deposited in the river, the plant is settled in the formed terrain, and when another disturbance of the scale that does not erode there occurs after the plant is settled, the river gradually grows and the vegetation zone is formed there. In particular, in terms of river management, river forestation and river aggradation are objects that must be managed because they are disadvantageous in terms of flood control by lowering the flow rate and raising the water level. Therefore, in this study, the area of vegetation occupied by the year of sandbar was analyzed in the process of river aggradation in Jang-Hang wetland. In addition, the correlation between the growth of Jang-Hang wetland was analyzed through the analysis of the flow rate and the flooding frequency that directly affect the growth of Jang-Hang wetland. Through this, the management plan of Jang-Hang wetland, which is registered in Ramsar Wetland but has been river forestation and is undergoing river aggradation, was proposed.

A Study on Determinants of Venture Capital Investments During Economic Booms and Busts (경제 호황과 후퇴의 시기에 벤처캐피탈 투자 의사결정요인 비교연구)

  • Kim, Jinsoo;Park, Ji-Hoon;Lee, Sang-Myung
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.19 no.1
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    • pp.1-21
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    • 2024
  • Recently, venture capital investment has been shrinking globally due to high interest rates and economic slowdown. Korea is no exception. Due to the downturn in the M&A and public markets, increasing economic uncertainty, and the aftermath of corporate bankruptcies, venture capitalists are facing many difficulties in raising funds. In the changed economic environment, the investment decision factors of venture capitalists have also changed. However, studies on VCs' investment decisions have focused on the general economic environment. This study examines how VCs' investment decision-making factors change during economic recessions and booms. To this end, we interviewed active investors who have experienced both economic recessions and booms to compare how VCs' investment decision factors change: 1) personal characteristics of founders, 2) experience of founders, 3) product/service, 4) market, 5) financial situation, 6) contract terms and 7) venture capital co-investment. The results showed that founder's personal characteristics, experience, and product/service were more important during the economic recession. Market is slightly more important during economic booms. The importance of financial situation and investment conditions increased sharply during the recession compared to the boom. Finally, venture capital co-investment did not differ significantly between recessions and booms. By understanding the investment decision-making factors of venture capitalists in the recent difficult venture investment environment, this study aims to help startups raise funds and survive in a difficult market.

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Field and laboratory investigation of highly pathogenic avian influenza H5N6 and H5N8 in Quang Ninh province, Vietnam, 2020 to 2021

  • Trong Duc Tran;Suwicha Kasemsuwan;Manakorn Sukmak;Waraphon Phimpraphai;Tippawon Prarakamawongsa;Long Thanh Pham;Tuyet Bach Hoang;Phuong Thi Nguyen;Thang Minh Nguyen;Minh Van Truong;Tuan Pham Dao;Pawin Padungtod
    • Journal of Veterinary Science
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    • v.25 no.2
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    • pp.20.1-20.15
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    • 2024
  • Background: Avian influenza (AI) is a contagious disease that causes illness and death in poultry and humans. High pathogenicity AI (HPAI) H5N6 outbreaks commonly occur in Quang Ninh province bordering China. In June 2021, the first HPAI H5N8 outbreak occurred at a Quang Ninh chicken farm. Objectives: This study examined the risk factors associated with HPAI H5N6 and H5N8 outbreaks in Quang Ninh. Methods: A retrospective case-control study was conducted in Quang Ninh from Nov 2021 to Jan 2022. The cases were households with susceptible poultry with two or more clinical signs and tested positive by real-time reverse transcription polymerase chain reaction. The controls were households in the same village as the cases but did not show clinical symptoms of the disease. Logistic regression models were constructed to assess the risk factors associated with HPAI outbreaks at the household level. Results: There were 38 cases with H5N6 clade 2.3.4.4h viruses (n = 35) and H5N8 clade 2.3.4.4b viruses (n = 3). Compared to the 112 controls, raising poultry in uncovered or partially covered ponds (odds ratio [OR], 7.52; 95% confidence interval [CI], 1.44-39.27), poultry traders visiting the farm (OR, 8.66; 95% CI, 2.7-27.69), farms with 50-2,000 birds (OR, 3.00; 95% CI, 1.06-8-51), and farms with ≥ 2,000 birds (OR, 11.35; 95% CI, 3.07-41.94) were significantly associated with HPAI outbreaks. Conclusions: Combining biosecurity measures, such as restricting visitor entry and vaccination in farms with more than 50 birds, can enhance the control and prevention of HPAI in Quang Ninh and its spread across borders.

Placement of a Subclavian Tunneled Hemodialysis Catheter with the Patient's Arm Raised May Reduce the Risk of Complications: Two Cases Report (쇄골하정맥을 통한 매립혈액투석카테터 삽입시 상지 거상법의 유용성: 2예 보고)

  • Jimin Yoo;Dong Jae Shim;Doyoung Kim;Seung Hwan Baek;Chang Suk Park;Jeong Whee Lee
    • Journal of the Korean Society of Radiology
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    • v.84 no.2
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    • pp.477-482
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    • 2023
  • The subclavian vein is an uncommon route for tunneled hemodialysis catheter (tHDC) placement because of its potency for future dialysis access. However, when favored access routes have been exhausted because of repeated catheterization or limited life expectancy, the subclavian vein can be used for urgent hemodialysis. A subclavian catheterization has a technical problem. The subclavian vein often forms a right angle with the vena cava, and advancing stiff peel-away sheath can cause a vascular injury. However, raising the patient's arm can alter the position of the guidewire and, therefore, change the angle of the vein favorable for tHDC placement. Herein, we report two patients who underwent subclavian catheterization; one experienced an injury to the superior vena cava after undergoing the conventional procedure, whereas the other patient with raised arm during the catheterization procedure had safe catheter placement.

Voice range differences in vowels by voice classification among male students of popular music vocals (대중가요 보컬 전공 남학생의 성종에 따른 모음 간 음역 차이)

  • Il-Song Ji;Jaeock Kim
    • Phonetics and Speech Sciences
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    • v.16 no.2
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    • pp.37-47
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    • 2024
  • This study was conducted on 27 male students majoring in or preparing for popular music vocals to determine whether they were aware of their voice classification and vocal range. Additionally, differences in the fundamental frequency and average speaking fundamental frequency were compared among the voice classifications. Moreover, considering that they may differ in their ability to produce high frequencies depending on the vowel, differences in voice ranges among the cardinal vowels, /a/, /i/, and /u/, were examined, and differences in voice ranges between vowels were compared by voice classification. The results showed that more than half of the male students majoring in or preparing for popular music vocals were not accurately aware of their voice types. In addition, statistically significant differences were found in the maximum fundamental frequency and frequency range among vowels, indicating differences in the voice range that can be produced depending on the vowel type. In particular, the voice range decreased in the following order: /a/>/u/>/i/. This suggests that while the vowel /a/ is easier to articulate in the high register compared to other vowels, vowels /u/ and /i/ as high vowels involve narrowing of the oral cavity due to the raised position of the tongue, accompanied by raising of the larynx, resulting in a decrease in voice range and difficulty in vocalizing in the high register.

The Effect of Rice Straw and Tall Fescue Hay for Holstein Heifers on the Productivity and Economics of Lactating Cow (홀스타인 육성기에 볏짚 및 톨페스큐 건초 급여가 착유우의 생산성 및 경제성에 미치는 영향)

  • Jin Su Ryu;Shin Ja Lee;Hyun Jin Kim;Sung Sill Lee
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.44 no.2
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    • pp.83-91
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    • 2024
  • We compared the reproductive performance, non-productive performance, and milk composition performance of two groups of lactating cows that were either rice straw or tall fescue. We also compared and analyzed these parameters after the first parturition during the breeding period. The calving interval, artificial insemination, and duration from calving to conception were longer in the rice straw group than in the tall fescue group. The 305-day and peak milk yields were significantly higher in the tall fescue group than in the rice straw group (p<0.01). Milk fat content was significantly higher in the tall fescue group than in the rice straw group (p<0.001), but milk protein content was the same between the feeding groups. The difference in raw milk sales income between rice straw and tall fescue groups tended to increase as the number of lactations increased, but there was no effect of reduced feed costs. Analysis of the milk production and raw milk sales income of the surveyed farms revealed that the average milk production per head was significantly (p<0.05) higher in the tall fescue group than in the rice straw group, and raw milk sales income showed a similar tendency. Overall, these results provide important details to be considered when selecting feed as a way to reduce milk production and heifer raising costs. However, there remains a need for future follow-up studies exploring the relationship between feed choice and the management of heifers.

Assessment of wetland ecosystem services for ecological management in the border area of the Han River Estuary (한강하구 접경지역 습지 생태계 서비스 평가를 통한 생태적 관리 방안 분석)

  • Hyun-Ah Choi;Donguk Han;Woo-Kyun Lee;Cholho Song
    • Korean Journal of Environmental Biology
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    • v.41 no.4
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    • pp.683-696
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    • 2023
  • The conservation of wetland ecosystems has a significant role in climate change. Notably, the Han River Protected Area, including the Siam-ri wetland and Janghang wetland, provides high biodiversity value. Thus, it is necessary to comprehensively evaluate the function and value of wetland ecosystems. This study evaluated the ecosystem services of Siam-ri and Janghang Wetlands located in the Han River Protected Area using the Rapid Assessment Wetland Ecosystem Services approach, a function-oriented ecosystem analysis. The results were calculated using the Ecosystem Services Index formula to analyze wetland ecosystem services. We also assessed the key ecosystem services based on a focus group interview. We identified that the supporting and cultural services index scores were relatively high in the study area. The results can provide helpful information for sustainable wetland conservation, conservation planning as primary data, and raising awareness for the Han River Protected Area.

First Record of the Invasive Alien Mollusk Melanoides tuberculata (Müller, 1774) (Gastropoda, Thiaridae) in South Korea (침입성 외래연체동물 서양다슬기(Melanoides tuberculata)에 대한 국내 최초 기록)

  • Youngjun Park;Soon Jae Eum;Youngho Cho;Yonglak Jeon;Yungchul Jun;InChul Hwang;Soon Jik Kwon
    • Korean Journal of Ecology and Environment
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    • v.57 no.3
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    • pp.162-168
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    • 2024
  • The purpose of this study was to record for the first time in Korea the presence of Melanoides tuberculata (an invasive alien species), which was confirmed during the "National Survey on the Status of Alien Species" in Jukdang stream (also known as Guppy Stream, located in Icheon, Gyeonggi Province), which is affected by the year-round discharge of heated effluent from a large semiconductor factory and where various tropical organisms, including ornamental fish, appear due to artificial release. A Total of 52 specimens were collected, and they can be visually distinguished from native melanian snails by their reddish-brown flames and spots. Genetic analysis further confirmed the species as Melanoides tuberculate. Melanoides tuberculata typically inhabits tropical climates, but its presence has been confirmed in altered aquatic environments such as Jukdang stream, where the water temperature remains warm even in a temperate climate. This indicates the need for further monitoring of domestic streams with similar conditions, particularly those receiving heated effluent, like Jukdang stream. Additionally, due to its strong reproductive capacity, including parthenogenesis, and its adaptability to various environments, there have been cases where the populations of Pomacea lineata and Aylacostoma tenuilabris have declined. This suggests that Melanoides tuberculata may have a competitive advantage in interspecific competition, potentially suppressing native species populations if it spreads within the domestic ecosystem. Melanoides tuberculata serves as an intermediate host for parasites that can cause diseases in both humans and animals, raising public health concerns in many countries. There is also a significant risk that it could be mistaken for native melanian snail species and consumed, which necessitates a high level of caution.

A Study on the Development of AI Utilization Guide Components at a Christian University (기독교대학의 AI활용가이드 구성요소 개발 연구)

  • Sungwon Kam;Minho Kim
    • Journal of Christian Education in Korea
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    • v.77
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    • pp.171-201
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    • 2024
  • Purpose of Research : Since ChatGPT's 2022 release, the educational sector faces mixed reactions to generative AI, sparking innovation but raising concerns about student cognition and communication. While Christian colleges employ AI reflecting their values, secular institutions stress ethical usage. This study explores ethical AI use in these settings, aiming to integrate findings into educational practices. Research content and method : Analyzing AI use and ethics guidelines from 50 domestic and international universities, differences between Christian and secular institutions were explored. Data was categorized, conceptualized via open coding, and components were identified through axial coding. The importance of components for Christian colleges' AI guides was assessed based on the initial data and previous research, leading to the development of tailored AI utilization components for Christian universities. Conclusion : Studies revealed secular institutions have six AI guide components, while Christian colleges found seven in both utilization and ethics guides, focusing on truthfulness, responsibility, and diversity. Emphasizing the need for ethical AI use in Christian colleges, the findings advocate developing AI ethics guidelines to aid marginalized groups and establish a new educational paradigm through further research.

Review of No Net Loss(NLL) of Wetland and Suggestion of Appropriate NLL in Korea (내륙습지 총량관리제도의 고찰 및 도입 방안 제안)

  • Yujin Kang;Junhyeong Lee;Taewoo Lee;Duckgil Kim;Jaeseung Seo;Soojun Kim;Hung Soo Kim
    • Journal of Wetlands Research
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    • v.26 no.3
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    • pp.227-235
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    • 2024
  • Inland wetlands provide important ecosystem services or functions, including biodiversity conservation, water purification, flood control, and carbon sequestration. However, many inland wetlands are being degraded by urbanization and industrialization, raising the need for conservation and restoration. This study proposes the adoption of No Net Loss(NLL) of Wetland for wetland conservation and restoration in Korea by the review of the literatures. To this end,, we analyzed the wetland conservation and management systems of the United States, Canada, Germany, Japan, and Australia, and identified institutional features and success factors of each country, and sought ways to adapt them to domestic conditions of Korea. The case of the United States highlights the importance of legal frameworks and public-private collaboration, Canada demonstrates systematic management approaches, Germany maintains a balance between development and conservation, Japan underscores the need for cooperative conservation efforts, and Australia emphasizes the efficiency of offset markets. The introduction and operation of these schemes are expected to contribute to climate change mitigation, biodiversity conservation, and water quality improvement, but ongoing research and policy efforts are needed to ensure that the schemes are well established.