• Title/Summary/Keyword: Multi-objectives

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A Study on Occupational Environment Assessment Strategies for Respirable Particulate Matter at Coal-Fired Power Plants (석탄화력발전소 호흡성분진 작업환경 평가 전략 사례에 관한 연구)

  • Eun-Seung Lee;Yun-Keun Lee;Dong-Il Shin
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.33 no.3
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    • pp.375-383
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    • 2023
  • Objectives: Coal-fired power plants feature diverse working conditions, including multi-layered employment structures and irregular work cycles due to outsourcing and non-standardized tasks. The current uniform occupational environment measurement systems have limitations in accurately assessing and evaluating these varied conditions. This study aims to propose alternative measurement and assessment strategies to supplement existing methods. Methods: Major domestic coal-fired power plants were selected as the study targets. To prepare for the study and establish strategies, work processes were identified and existing occupational environment measurement results were compared and analyzed. The study proceeded by employing three strategies: specific exposure groups (SEGs) measurement, continuous monitoring, and supplementary measurements, which were then compared and discussed. Results: Previous exposure index evaluations (5,268 cases) indicated that crystalline silica, a type of respirable particulate matter, had detection limits below the threshold (non-detectable) in 82.6% (4,349 cases) of instances. Exposures below 10% of the exposure limit were observed at a very low concentration of 96.1%. Similar exposure group measurements yielded results where detection limits were below the threshold in 38.2% of cases, and exposures below 10% of the limit were observed in 70.6%. Continuous monitoring indicated detection limits below the threshold in 12.6% of cases, and exposures below 10% of the limit were observed in 75.6%. Instances requiring active workplace management accounted for more than 30% of cases, with SEGs at 11.8% (four cases), showing a higher proportion compared to 3.0% (four cases) in continuous monitoring. For coal dust, exposures below 10% of the limit were highest in legal measurements at 90.2% (113 cases), followed by 74.0% (91 cases) in continuous monitoring, and 47.0% (16 cases) in SEGs. Instances exceeding 30% were most prevalent in SEGs at 14.7% (five cases), followed by legal measurements at 5.0% (eight cases), and continuous monitoring at 2.4% (three cases). When examining exposure levels through arithmetic means, crystalline silica was found to be 104.7% higher in SEGs at 0.0088 mg/m3 compared to 0.0043 mg/m3 in continuous monitoring. Coal dust measurements were highest in SEGs at 0.1247 mg/m3, followed by 0.1224 mg/m3 in legal measurements, and 0.0935 mg/m3 in continuous monitoring. Conclusions: Strategies involving SEGs measurement and continuous monitoring can enhance measurement reliability in environments with irregular work processes and frequent fluctuations in working conditions, as observed in coal-fired power plants. These strategies reduce the likelihood of omitting or underestimating processes and enhance measurement accuracy. In particular, a significant reduction in detection limits below the threshold for crystalline silica was observed. Supplementary measurements can identify worker exposure characteristics, uncover potential risks in blind spots of management, and provide a complementary method for legal measurements.

Spatial Analysis of Carbon Storage in Satellite Radar Imagery Utilizing Sentinel-1: A Case Study of the Ungok Wetlands (위성 레이더 영상 중 Sentinel-1을 활용한 탄소 흡수원 공간분석 - 운곡습지를 대상으로 -)

  • Ha-Eun Yu;Young-Il Cho;Shin-Woo Lee;Moung-Jin Lee
    • Korean Journal of Remote Sensing
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    • v.39 no.6_3
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    • pp.1731-1745
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    • 2023
  • Within the framework of the post-2020 climate regime, the Paris Agreement's emphasis on Nationally Determined Contributions and Biennial Transparency Reporting is paramount in addressing its long-term temperature goal. A salient issue is the treatment of wetland ecosystems within the context of Land Use, Land-Use Change, and Forestry, as defined by the Intergovernmental Panel on Climate Change. In the 2019 National Inventory Report, wetlands were recategorized as emission sources due to their designation as inundated areas. This study employs C-band radar imagery to discriminate between inundated and non-inundated regions of wetlands, enabling the quantification of their spatial dynamics. The research capitalizes on 24-period Sentinel-1 satellite data to cover both the inundation and desiccation phases while centering its attention on Ungok Wetland, a Ramsar-designated inland wetland conservation area in Korea. The inundated area is quantitatively assessed through the integration of multi-temporal Sentinel-1 Single-Look Complex (SLC) data, aerial orthophotography, and inland wetland spatial information. Furthermore, the study scrutinizes fluctuations in the maximum and minimum inundated areas, with substantial changes corroborated via drone aerial reconnaissance. The outcomes of this investigation hold the potential to make substantive contributions to the refinement of national greenhouse gas absorption and emission factors, thereby informing the development of comprehensive greenhouse gas inventories. These efforts align directly with the overarching objectives of the Paris Agreement.

An Exploratory Study on the Trustworthiness Analysis of Generative AI (생성형 AI의 신뢰도에 대한 탐색적 연구)

  • Soyon Kim;Ji Yeon Cho;Bong Gyou Lee
    • Journal of Internet Computing and Services
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    • v.25 no.1
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    • pp.79-90
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    • 2024
  • This study focused on user trust in ChatGPT, a generative AI technology, and explored the factors that affect usage status and intention to continue using, and whether the influence of trust varies depending on the purpose. For this purpose, the survey was conducted targeting people in their 20s and 30s who use ChatGPT the most. The statistical analysis deploying IBM SPSS 27 and SmartPLS 4.0. A structural equation model was formulated on the foundation of Bhattacherjee's Expectation-Confirmation Model (ECM), employing path analysis and Multi-Group Analysis (MGA) for hypothesis validation. The main findings are as follows: Firstly, ChatGPT is mainly used for specific needs or objectives rather than as a daily tool. The majority of users are cognizant of its hallucination effects; however, this did not hinder its use. Secondly, the hypothesis testing indicated that independent variables such as expectation- confirmation, perceived usefulness, and user satisfaction all exert a positive influence on the dependent variable, the intention for continuance intention. Thirdly, the influence of trust varied depending on the user's purpose in utilizing ChatGPT. trust was significant when ChatGPT is used for information retrieval but not for creative purposes. This study will be used to solve reliability problems in the process of introducing generative AI in society and companies in the future and to establish policies and derive improvement measures for successful employment.

The Effect of Community- and Individual-Level Factors on Suicidal Ideation and Attempts: A Multilevel Analysis (2021년 지역사회건강조사를 활용한 지역사회 및 개인 수준의 요인이 자살 생각과 자살 시도에 미치는 영향: 다수준 분석)

  • So Young Ha;Jinhwan Kim;Haegyun Park;Youngsoo Kim
    • Korean Journal of Psychosomatic Medicine
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    • v.32 no.1
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    • pp.24-33
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    • 2024
  • Objectives : The purpose of this study was to investigate individual- and community-level factors on suicidal ideation and suicide attempt among Korean adults. Methods : This study was conducted on 225,965 adults collected through data from the 2021 Community Health Survey and the Korean Statistical Information Service (KOSIS). The general characteristics, suicidal behavior (e.g., suicidal ideation, and suicide attempts), and community-level characteristics of the study subjects were analyzed using frequency (%) and mean (standard deviation). The effects on individual- and community-level factors on suicidal ideation and suicide attempts was analyzed using multilevel logistic regression models. Results : The community-level factor associated with suicidal ideation was unmet health care (Odds Ratio [OR]=1.053, 95% CI=1.035-1.071), and the community-level factor associated with suicide attempt was the aging rate (OR=1.015, 95% CI=1.001-1.030). Regarding health-related variables, the individual-level factors associated with suicidal ideation were stress status (OR=9.388, 95% CI=8.629-10.213), depressive experience in the past year (OR=6.737, 95% CI=6.454-7.032), and the predominantly individual-level factors associated with suicide attempt were also stress status (OR=5.213, 95% CI=3.699-7.347), and depressive experience in the last one year (OR=13.433, 95% CI: 11.247-16.044). Conclusions : We confirmed individual-level and community-level factors influencing suicidal ideation and suicide attempt. Through these findings, we need to establish suicide prevention policies, considering managing individual-level factors such as stress and depression as well as community-level factors such as unmet health care.

Optimal Dose of Edoxaban for Very Elderly Atrial Fibrillation Patients at High Risk of Bleeding: The LEDIOS Registry

  • Ju Youn Kim;Juwon Kim;Seung-Jung Park;Kyoung-Min Park;Sang-Jin Han;Dae Kyeong Kim;Yae Min Park;Sung Ho Lee;Jong Sung Park;Young Keun On
    • Korean Circulation Journal
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    • v.54 no.7
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    • pp.398-406
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    • 2024
  • Background and Objectives: Optimal anticoagulation in very elderly patients is challenging due to the high risk of anticoagulant-induced bleeding. The aim of this study was to assess outcomes of on-label reduced-dose edoxaban (30 mg) in very elderly patients who had additional risk factors for bleeding. Methods: This was a multi-center, prospective, non-interventional observational study to evaluate the efficacy and safety of on-label reduced-dose edoxaban in atrial fibrillation (AF) patients 80 years of age or older and who had more than 1 risk factor for bleeding. Results: A total of 2448 patients (mean age 75.0±8.3 years, 801 [32.7%] males) was included in the present study, and 586 (23.9%) were 80 years of age or older with additional risk factors for bleeding. Major bleeding events occurred frequently among very elderly AF patients who had additional bleeding risk factors compared to other patients (unadjusted hazard ratio [HR], 2.16; 95% confidence interval [CI], 1.16-4.02); however, there were no significant differences in stroke incidence (HR, 1.86; 95% CI, 0.98-3.55). There were no significant differences for either factor after adjusting for age and sex (adjusted HR, 1.65; 95% CI, 0.75-3.62 for major bleeding; adjusted HR, 1.13; 95% CI, 0.51-2.50 for stroke). Conclusions: In very elderly AF patients with comorbidities associated with greater risk of bleeding, the incidence of major bleeding events was significantly increased. In addition, risk of stroke showed tendency to increase in same population. Effective anticoagulation therapy might be important in these high-risk population, and close observation of bleeding events might also be required.

In Vitro Antioxidant Activity and Anticonvulsant Properties on Zebrafish PTZ-Induced Seizure Model of a Tilia viridis Aqueous Extract

  • Elina Malen Saint Martin;Ayelen Morena Sosa;Carolina Soledad Martinez;Jimena Prieto;Carla Marrassini;Cecilia Beatriz Dobrecky;Maria Rosario Alonso;Claudia Anesini
    • Journal of Pharmacopuncture
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    • v.27 no.3
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    • pp.211-222
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    • 2024
  • Objectives: Tilia viridis (Bayer) Simonk. (Malvaceae) is widely distributed in Argentina and employed for its tranquilizing properties. Other species of the genus (Tilia europaea L., Tilia cordata Mill., Tilia platyphyllos Scop.) have been traditionally used for the treatment of epilepsy. Epilepsy affects approximately 65 million people worldwide and is characterized by an imbalance between excitatory and inhibitory processes in the brain, leading to unpredictable, unprovoked, recurrent seizures. Current pharmacological interventions often present mild to moderately severe side effects. Epilepsy has been associated with oxidative and nitrative stress as well as neuroinflammation. Herbal medicine therapies may offer new treatment options with multi-target antioxidant and anticonvulsant effects for patients whose seizures remain uncontrolled, potentially providing cost-effective solutions for individuals worldwide suffering from uncontrolled epilepsy.The aim of this study was to demonstrate the anticonvulsant activity of a standardized T. viridis aqueous extract (TE). Methods: Study of the constituents of TE, TE's antioxidant and anticonvulsant activities and toxicity, and analysis of the possible relation between the potential activities and the compounds present in the extract. In order to demonstrate TE's anticonvulsant activity a zebrafish model was used. The study also assessed TE's toxicity and antioxidant activity. To standardize the extract, total polyphenols and flavonoids were quantified and specific flavonoids were identified and quantified using HPLC-MS/MS and HPLC-UV. Results: TE exhibited anticonvulsant activity at low concentrations and demonstrated antioxidant effects by scavenging free radicals, exhibiting superoxide dismutase and peroxidase-like activities, as well as inhibiting lipoperoxidation. These actions can be attributed to the presence of polyphenols, particularly flavonoids. Conclusion: TE holds promise as a complementary herbal medicine in the treatment of epilepsy and may also offer benefits for other neuropathies associated with oxidative stress, such as Parkinson's disease and Alzheimer's disease.

A Study on Teaching-Learning and Evaluation Methods of Environmental Studies in the Middle School (중학교 "환경" 교과의 교수.학습 및 평가 방법 연구)

  • 남상준
    • Hwankyungkyoyuk
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    • v.7 no.1
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    • pp.1-17
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    • 1994
  • This study was performed to determine appropriate teaching-learning and evaluation methods for Environmental Studies. To promote the relevance of our study to the needs of the schools and concerned educational communities of environmental education, we reviewed related literature, conducted questionnaire surveys, interviewed related teachers and administrator, held meetings with experts, and field-tested our findings. For selecting and developing teaching-learning methods of Environmental Studies, findings of educational research in general are considered. moreover, principles of environmental education, general aim of environmental education, orientations of environmental education, and developmental stages of middle school students in educational psychology were attended. In addition, relevance to the purpose of the Environmental Studies curriculum, appropriateness for value inquiry as well as knowledge inquiry, small group centered class organization, social interaction centered teaching-learning process, regional environmental situation, significance of personal environment, evaluation methods of Environmental Studies, multi- and inter-disciplinary contents of the Environmental Studies textbook, suitability to the evaluation methods of Environmental Studies, and emphasis on the social interaction in teaching-learning process were regarded. It was learned the Environmental Studies can be taught most effectively in via of holding discussion sessions, conducting actual investigation, doing experiment-practice, doing games and plate, role-playing and carrying out simulation activities, and doing inquiry. These teaching-learning methods were field-tested and proved appropriate methods for the subject. For selecting and developing evaluation method of Environmental Studies, such principles and characteristics of Environmental Studies as objective domains stated in the Environmental Studies curriculum, diversity of teaching-learning organization, were appreciated. We categorized nine evaluation methods: the teacher may conduct questionnaire surveys, testings, interviews, non-participatory observations; they may evaluate student's experiment-practice performances, reports preparation ability, ability to establish a research project, the teacher may ask the students to conduct a self-evaluation, or reciprocal evaluation. To maximize the effect of these methods, we further developed an application system. It considered three variables, that is, evaluates, evaluation objectives domains, and evaluation agent, and showed how to choose the most appropriate methods and, when necessary, how to combine uses of different methods depending on these variables. A sample evaluation instrument made on the basis of this application system was developed and tested in the classes. The system proved effective. Pilot applications of the teaching-learning methods and evaluation method were made simultaneously; and the results and their implications are as follows. Discussion program was applied in a lesson dealing with the problems of waste disposal, in which students showed active participation and creative thinking. The evaluation method used in this lesson was a multiple-choice written test for knowledge and skills. It was shown that this evaluation method and device are effective in helping students' revision of the lesson and in stimulating their creative interpretations and responces. Pupils showed great interests in the actual investigation program, and this programme was proved to be effective in enhancing students' participation. However, it was also turned out that there must be pre-arranged plans for the objects, contents and procedures of survey if this program is to effective. In this lesson, non-participatory observation methods were used with a focus on the attitudes of students. A scaled reported in general description rather than in grade. Experiment-practice programme was adopted in a lesson for purifying contaminated water and in this lesson, instruction objectives were properly established, the teaching-learning process was clearly specified and students were highly motivated. On the other hand, however, it was difficult to control the class when some groups of students require more times to complete their experiment, and sometimes different results. As regards to evaluation, performance observation test were used for assessing skills and attitudes. If teachers use well-prepared Likert scale, evaluation of all groups within a reasonablely short period of time will be possible. The most effective and successful programme in therms of students' participation and enjoyment, was the 'ah-nah-bah-dah-market' program, which is kind of game of the flea market. For better organized program of this kind, however, are essential, In this program, students appraise their own attitudes and behavior by responding to a written questionnaire. In addition, students were asked to record any anecdotes relating to self-appraisal of changes on one's own attitudes and behaviours. Even after the lesson, students keep recording those changes on letters to herself. Role-playing and simulation game programme was applied to a case of 'NIMBY', in which students should decide where to located a refuse dumping ground. For this kind of programme to e successful, concepts and words used in the script should be appropriate for students' intellectual levels, and students should by adequately introduced into the objective and the procedures of the lessons. Written questionnaire was used to assess individual students' attitudes after the lesson, but in order to acquire information on the changes of students' attitudes and skills, pre-test may have to be made. Doing inquiry programme, in which advantages in which students actually investigated the environmental influence of the areas where school os located, had advantages in developing students' ability to study the environmental problems and to present the results of their studies. For this programme to be more efficient, areas of investigation should be clearly divided and alloted to each group so that repetition or overlap in areas of study and presentation be avoided, and complementary wok between groups bee enhanced. In this programme, teacher assessed students' knowledge and attitudes on the basis of reports prepared by each group. However, there were found some difficults in assessing students' attitudes and behaviours solely on the grounds of written report. Perhaps, using a scaled checklist assessing students' attitudes while their presentation could help to relieve the difficulties.

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The Effects of CEO's Narcissism on Diversification Strategy and Performance in an Economic Downturn: The Moderating Role of Corporate Governance System (경기침체기의 다각화전략과 성과에 대한 최고경영자 나르시시즘의 영향과 기업지배구조의 조절효과에 대한 연구)

  • Yoo, Jae-Wook
    • Management & Information Systems Review
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    • v.35 no.4
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    • pp.1-19
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    • 2016
  • The researchers in strategic management have focused on identifying the effects of CEO's demographic characteristics and experience on the strategic choices and performance of firms. On the other hand, they have failed to identifying the effects of CEO's psychological characteristics on them because of the difficulties over data collection and measurement for variables. To overcome this limitation of prior researches, this study is designed to achieve two specific objectives. The first is to examine the effect of CEO narcissism on diversification strategy and performance of listed corporations on Korean securities market in an economic downturn. The other is to examine the moderating effects of various corporate governance systems that are related to board and/or ownership structures on those relationships. The empirical setting for this study was drawn from a multi-year(2011~2014) sample of large listed corporations in Korean securities market. To achieve the objectives, the hypotheses of research are analyzed by implementing multiple regression analyses in two separate models. The results of these analyses show that CEO narcissism is positively related to the diversification of listed large corporations in Korean securities market. Regrading the moderating effects, the stake of institutional investors weakens the positive relationship between CEO narcissism and firm's diversification. The findings of this research imply that CEO narcissism can intensify the tendency of Korean corporations to adopt high-risk and high return strategy in an economic downturn. Thus, firms might be able to use CEO narcissism to drastically restructure the business portfolio in an economic downturn. However, Korean corporations should be very cautions to maximize the positive effect of CEO narcissism. They might be use the institutional investors as their corporate governance system to monitor and control the opportunism of CEO in the decision for diversification in an economic downturn.

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Effect of Cardiotonic Pills$^{(R)}$ on Chest Pain and Discomfort: A Multi-center Double-blind Randomized Controlled Trial. (심적환$^{(R)}$이 흉통 흉민에 대하여 미치는 영향에 대한 다기관 무작위배정 이중맹검 임상연구)

  • Jang Insoo;Ko Changnam;Lee In;Park Jung-mi;Kim Sehyun;Kim Sangwoo
    • The Journal of Korean Medicine
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    • v.26 no.2 s.62
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    • pp.95-104
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    • 2005
  • Objectives: This was a double blinded, randomized, placebo-controlled clinical study for evaluation of safety and effective dose finding of Cardiotonic Pills$^{(R)}$ in patients with chest pain and discomfort. Cardiotonic Pills$^{(R)}$ are composed of Salviae Miltiorrhizae Radix (丹蔘), Notoginseng Radix (三七根) and Borneolum (龍腦). Major effects of Salviae Miltiorrhizae Radix and Notoginseng Radix are vasodilatation, sedation and analgesic action. Borneolum has an antibacterial effect, and can stimulate the central nervous system. All of these substances are oriental herbs that have been used for a long time in east Asia. Cardiotonic Pills fi received Investigational New Drug (IND) approval from the Food and Drug Administration (FDA) in the USA and 40 million people in the world take this pill. We performed a phase IV clinical study to confirm its efficacy and safety in patients who have probable cardiogenic or psychogenic chest pain or chest stifling. Methods: This study was planned for a multi-center clinical trial including four university hospitals of oriental medicine in Korea. This was the first time to evaluate the 'planning treatment according to diagnosis (辨證施治)' of chest pain or chest discomfort according to oriental medical guidelines. The patients who were included in this trial were adult volunteers from 20 to 70 years old who had chest pain or chest discomfort more than twice during a recent month, and we received written consent to participate in this study from all of them. After administration of Cardiotonic Pills$^{(R)}$ for 8 weeks, number of occurrences, duration, appearance and degree of chest pain or chest discomfort was observed and degree of symptoms (severity of illness, global improvement) were measured using a patient's global assessment composite scale. Results: In the patient's global assessment scale, the severity of illness of the Cardiotonic Pills$^{(R)}$ group (n=25) was 14/25=0.56 but of the placebo group (n=25) was 7/25=0.28 (p-value=0.0449). This result indicates Cardiotonic Pills$^{(R)}$have a positive effect on the symptoms of chest pain and discomfort. However, the global improvement of the Cardiotonic Pills$^{(R)}$group was 23/25=0.92, and of the placebo group was 22/25=0.88 (p-value=0.6374). The total symptom score of the Cardiotonic Pills$^{(R)}$ group was $1.68\pm20.06$, and of the placebo group was $16.76\pm72.l4$(p-value=0.2285). The number of symptom events of the Cardiotonic Pills$^{(R)}$ group was $72\pm29.78$, and of the placebo group (n=25) was $10.80\pm38.42$ (p­value=0.3660). We could not find any effects on the other factors examined besides the severity of illness, beyond the difference of standard deviations. Conclusions: Cardiotonic Pills$^{(R)}$ significantly reduced chest pain and chest discomfort in patients. Therefore, we expect that Cardiotonic Pills$^{(R)}$ will be helpful for patients with chest pain and chest discomfort not only caused by heart disease but also by other diseases.

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Preliminary Environmental Impact Assessments on Fish Compositions and the Ecological Health of Jeokbyeok River on the Road Construction of Muju-Geumsan Region (무주-금산간 도로건설에 따른 적벽강의 어류 종 조성 분석 및 생태건강도 사전환경성평가)

  • Lee, Sang-Jae;Park, Hee-Sung;An, Kwang-Guk
    • Journal of Environmental Impact Assessment
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    • v.26 no.1
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    • pp.27-43
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    • 2017
  • The objectives of the study were to evaluate fish compositions, endangered species, community structure, physical habitat, and general water quality for a preliminary environmental impact assessment of Jeokbyeok River on the road construction between two regions. Total number of species and total number of individuals, based on CPUE, were 23 and 1186, respectively. The endangered species (I, II) as the legal protection species were Pseudopungtungia nigra (79 samples) Gobiobotia brevibarba) (5) Gobiobotia macrocephala (2), indicating a requiring of endangered species conservation. In the meantime, exotic species and ecological disturbing species such as Micropterus salmoides and Lepomis macrochirus, were not present, indicating a well conserved area. According to fish community analysis, values of species diversity index were high (range: 0.788 - 1.030), and the dominance index were low (range: 0.097 - 0.183), indicating that the fish community in this area was maintained well without high dominacne by specific species. Also, fish analysis on tolerance guilds and trophic guilds showed that the proportions of sensitive species were largely exceeded the proportions of the tolerant species, while the proportions of insectivore species were largely exceeded the proportions of the omnivore species. This outcome suggests that the ecosystem was well maintained in terms of tolerance and trophic compositions (food chain). Ecological health, based on the multi-metric fish model of Fish Assessment Integrity (FAI), reflected those fish conditions. In other words, values of FAI model averaged 82.4, which means a "good condition" in the criteria of ecological health by the Minstry of Environment, Korea. In addition, general water quality and physical habitat analyses showed that the system was in good condition. Under these conditions, if the road constructions between the two regions happen in the future, inorganic suspended solids may increase in the waterbody, and this may result in indirect or direct influences on the physical habitats and food chain as well as fish compositions, so the ecological protections and prevention strategy from the soil erosion are required in the system.