• Title/Summary/Keyword: Fish body

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Analysis of Effects of Multiple Environmental Factors on Early Life-history for Growth and Stress Accumulation Using a Dynamic-state-dependent Model (동적상태의존모델을 이용하여 복합적 환경영향이 어류의 초기 생활사에 미치는 영향 분석)

  • Lee, Who-Seung
    • Journal of Environmental Impact Assessment
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    • v.28 no.1
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    • pp.49-62
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    • 2019
  • Environmental changes can affect life-history traits, such as growth rate and reproduction, and organisms adapt on a given environmental condition to maximize ecological fitness. This study shows the effects of water temperature and dissolved oxygen level on early growth and accumulated damage in fish using a dynamic-state-dependent model. I have hypothesized that the level of foraging activity is related to growth and stress and so the optimal level can maximize reproductive success - ultimately, fitness. The critical temperature and dissolved oxygen (DO) is also defined as inducing the maximum growth rate at the level. So, the model predicts the highest growth rate at oxygen saturation and lower growth rate at lower or higher level of DO in water. Lower DO (i.e., hypoxia) causes slower growth rate through higher amount of accumulated stress whereas higher DO (i.e., hyperoxia) induces faster growth rate, but smaller body size. In addition, I show that there is lower impact when considering simple or independent environmental factors on environmental assessment. My findings suggest that multiple environmental factors as physiological ecology approach should be considered to improve impact assessment in environmental changes and a further study is needed to develop advanced assessment tools considering multiple environmental factors.

A Study on Quality Improvement through Analysis of Hub-reduction Failure Occurrence Mechanism for Military Vehicles (군용차량 허브리덕션 고장 메커니즘 분석을 통한 품질개선 연구)

  • Kim, Sung-Gon;Kim, Seon-Jin;Yun, Seong-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.6
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    • pp.188-196
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    • 2021
  • For the tactical vehicles operated by the Korean army, the hub-reduction portal axle was applied considering Korea's topographical characteristics. Hub-reduction was applied to a Korean military vehicle to increase the vehicle body to secure ground clearance and improve the driving capability on rough roads, such as unpaved and field land by increasing the torque. The Korean military is operating tactical vehicles after various performance tests, including durability driving, but wheel damage occurred in one of the vehicles operating in the front units. Failure analysis revealed many damaged parts, including the hub, making it difficult to determine the cause. Therefore, an analysis of the failure occurrence mechanism for each damaged part was conducted, which confirmed that the cause of wheel breakage was a hub. Furthermore, the root cause of the hub breakage was a crack due to internal pores and foreign matters. In addition, a realistic improvement plan that can be applied throughout the design, manufacture, and shipping stages was presented using the fishbone diagram analysis. The derived improvement plan was verified through unit performance tests, including CAE and actual vehicle tests, and by reflecting this, the driving safety of Korean tactical vehicles was improved. Finally, it is expected that the proposed method for analyzing the failure occurrence mechanism will be used as reference material when analyzing the quality problems of similar military vehicles in the future.

A comparison on health-related lifestyle, dietary habits, and depression by exercise frequency of college students

  • Kim, Jiwon;Choi, Onjeong;Lee, Yujin;Lee, Youngmi;Song, Kyunghee
    • Nutrition Research and Practice
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    • v.15 no.3
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    • pp.355-366
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    • 2021
  • BACKGROUND/OBJECTIVES: The study was performed to investigate health-related lifestyle, dietary habits, and depression according to exercise frequency to understand complex factors that affect effective health management. Thus, exercise frequency, health-related lifestyle, dietary habits, and depression were evaluated in college students in Seoul and Gyeonggi-do areas. SUBJECTS/METHODS: A survey was conducted on college students, aged 19-29, in Seoul and Gyeonggi-do areas from May 13 to May 31, 2020. A total of 594 questionnaires were collected and 566 (269 from males, 297 from females) were statistically analyzed, except 28 with incomplete responses. Collected data were analyzed using SPSS WIN 21.0 program. RESULTS: The sex distribution of the 3 groups according to exercise frequency was significantly different; the ratio of males in over 3 times/week group was significantly higher than those in 1-2 times/week group and no-exercise group (P < 0.001). The height (P < 0.001), weight (P < 0.001), and body mass index (P < 0.05) were significantly higher in over 3 times/week group compared to no-exercise group. The ratio of subjects who answered 'good' or 'very good' for subjective health condition was significantly high in the order of 'over 3 times/week' group (59.1%), '1-2 times/week' group (34.5%), and 'no-exercise' group (25.0%) (P < 0.001). The ratio for meal regularity was high as 56.6% in 'over 3 times/week' group and the ratio for irregular meals was significantly higher in 'no-exercise' group (67.2%) and '1-2 times/week' group (54.9%) (P < 0.001). Among questions on dietary habits, 'Eat meat, fish, egg or beans' (P < 0.01) and 'Eat fruit' (P < 0.01) were significantly higher in 'over 3 times/week' group compared to 'no-exercise' group. 'Drink more than 2 liters of water' (P < 0.001) was 0.70 in 'over 3 times/week' group, which was significantly higher than 0.54 in '1-2 times/week' group and 0.38 in 'no-exercise' group. Moderate depression and severe depression that need treatments were significantly lower in 'over 3 times/week' group (18.7%) compared to '1-2 times/week' group (26.0%) and 'no-exercise' group (29.7%) (P < 0.05). CONCLUSIONS: It is considered that combined intervention for exercise habits, proper dietary habits, and depression management is needed for effective health management.

Isolation and Characterization of Antibiotic Resistant Vibrio Strains from Japanese Eel (Anguilla Japonica) Cultured in Korea (국내산 양식 뱀장어에서 항생제 내성 비브리오 세균 분리 및 특성)

  • Park, S.Y.;Kim, J.H.;Jun, J.W.
    • Journal of Practical Agriculture & Fisheries Research
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    • v.22 no.2
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    • pp.51-58
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    • 2020
  • Continuous mortality in commercially cultured Japanese eel (Anguilla japonica), showing symptoms of dermal ulcerations and focal hemorrhages on the body, occurred on a private farm in November, 2019 in Korea. A series of mortality had been described in one local eel culture farm from November to December in 2019. From the three cases, three isolates of Vibrio spp. were recovered from the blood, ascitic fluid, and kidney of the dead fish, respectively. Based on the 16S rRNA sequence comparisons, the Vibrio isolates from the 1st and 3rd cases (strain named 1E1-2 and 3K1-2) were identified as V. fluvialis and the isolate from the 2nd case was identified as V. plantisponsor (strain named 2A3-1). Moreover, the 16S rRNA-based phylogenetic analysis revealed that strain 1E1-2 and 3K1-2 were most similar to V. fluvialis NBRC 103150T, and strain 2A3-1 was most similar to V. plantisponsor NBRC103148T. According to the results of the antibiotic resistance determination, V. fluvialis 1E1-2 showed intermediate resistance to tetracycline and chloramphenicol, and was resistant to trimethoprim-sulfamethoxazole. V. plantisponsor 2A3-1 showed intermediate resistance to ciprofloxacin and levofloxacin, and was resistant to trimethoprim-sulfamethoxazole. V. fluvialis 3K1-2 showed intermediate resistance to tetracycline, and was resistant to ampicillin and trimethoprim-sulfamethoxazole. These results have provided the evidences on the occurrence of antibiotic-resistant Vibrio infection in commercially cultured Japanese eels are present in Korea.

Microplastics in the Marine Environment and Their Impacts on Human Health (해양 환경의 미세 플라스틱과 인간의 건강에 미치는 영향)

  • Bak, Jia;Kang, Hyun Bon;Choi, Yun-Sik
    • Journal of Life Science
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    • v.31 no.4
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    • pp.442-451
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    • 2021
  • Microplastics are fragments of any type of plastic with a size less than 5 mm. Ocean pollution by microplastics is now a worldwide concern in relation to marine ecosystems and human health. The widespread contamination by microplastics means that they can be ingested by and accumulated in diverse species of wildlife, such as fish, mussels, oysters, clams, and scallops. Once ingested, the microplastics can be observed in the intestines, liver, and kidney, and even in the brain. Seafood is one of the major sources of protein intake in humans; therefore, seafood consumption could be pathway for human microplastics exposure. Accumulating evidence indicates that repeated oral exposure to microplastics induces pathologic and functional changes in the reproductive, cardiac, gastrointestinal, endocrine, and even nervous systems of rodents. Maternal exposure to microplastics during gestation and lactation alters metabolic homeostasis in the offspring. Given that seafood provides more than 20% of the total protein intake by over 310 million people worldwide, a reasonable assumption is that microplastics could be substantially accumulated in the human body and impair physiological function. In this review, we have summarized the current status of microplastics contamination in the ocean, their accumulation and toxicities in marine animals and rodents, their exposure to humans, and their potential impacts on human health.

Feeding Habits and Trophic Level of Blackthroat Seaperch, Doederleinia berycoides in the South Sea of Korea (한국 남해에서 출현하는 눈볼대(Doederleinia berycoides)의 식성과 영양단계)

  • Kim, Do-Gyun;Kim, Hyeon Ji;Lee, Seung-Jong;Baeck, Gun Wook
    • Korean Journal of Ichthyology
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    • v.34 no.3
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    • pp.172-178
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    • 2022
  • To investigate the feeding habits and trophic level of the blackthroat seaperch, Doederleinia berycoides in the South Sea of Korea, fish samples were collected by a bottom trawl net from fisheries resources survey vessels of NIFS in February, May, August and November 2021. The total length (TL) of these specimens was from 3.3 to 33.1 cm. D. berycoides fed majorly on Teleostei (especially Engraulis japonicus) based on index of relative importance (%IRI=64.4%). D. berycoides underwent an ontogenetic dietary shift. Smaller individuals (<10.0 cm TL) fed mainly on amphipods. The proportion of amphipods decreased as body size increased, whereas the consumption of Teleostei increased gradually. Examination of the feeding habits according to ontogentic feeding patterns in the diets of D. berycoides revealed that the mean weight of prey (mW/ST) continuously increased, while mean number of prey (mN/ST) decreased and then increased. The estimated average trophic level of the D. berycoides was 3.62±0.64, ranging from 3.31±0.52 to 3.79±0.70.

Blood Property and Biologger Attachment Efficiency of Spotted Sea bass Lateolabrax maculatus depending on External Biologger Attachment Methods (바이오로거 체외 부착방법이 점농어(Lateolabrax maculatus)의 혈액성상 및 바이오로거 부착효율에 미치는 영향)

  • Pil Jun Kang;Geun Su Lee;Sung-Yong Oh
    • Journal of Marine Life Science
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    • v.9 no.1
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    • pp.22-32
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    • 2024
  • The purpose of this study was to determine the effect of external biologger attachment methods on the blood parameters and attachment efficiency of spotted sea bass Lateolabrax maculatus (mean body weight 2630.8 g). The fish were tagged using four different external attachment methods with dummy biologgers: no attachment (control), anchor attachment (AA), monofilament attachment (MA), and silicon tube attachment (SA), each with triplicates. Blood indices and biologger attachment efficiency were assessed on days 1, 7, 14, 28, 56, and 84 after attachment. The concentrations of hematocrit, Na+, Cl-, glutamic pyruvic transaminase and total protein, and the activity of superoxide dismutase in blood were not affected by the external attachment method of biologger. The concentrations of glutamic oxaloacetic transaminase (day 1 of attachment), hemoglobin (day 56) and total cholesterol (day 56 and 84) in AA group, the concentrations of glucose and cortisol (day 14) and total cholesterol (day 84) in MA group showed significantly higher than those of control (p<0.05). During the experiment period, the SA group had no differences from the control in all blood properties. The biologger attachment efficiencies of the AA, MA, and SA groups after 84 days were 0.0%, 33.3%, and 100.0%, respectively. These results indicate that the optimum external biologger attachment method under our experimental conditions is SA type.

A Study on the Applicability of Acrylic Water Leak Repair Materials used to Repair Cracks in Conduits and Underground Structures (관거 및 지하구조물 균열 보수에 사용되는 아크릴 누수 보수재의 적용성에 대한 연구)

  • Eunmi Lee;Kyungik Gil
    • Journal of Wetlands Research
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    • v.26 no.2
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    • pp.139-146
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    • 2024
  • Various injection materials, such as asphalt-based injection materials, urethane-based injection materials, cement- based injection materials, and acrylic-based injection materials, are used for the repair of aged conduits and underground structures with cracks. In this study, research was conducted on an environmentally friendly acrylic- based leak repair material that exhibits good curing properties even in humid conditions and stability in temperature fluctuations. To compare the performance of the improved acrylic leak repair material with the existing acrylate injection material, experiments were conducted using KS standard methods, including underwater length change rate tests, underwater leakage resistance tests, and chemical performance tests. The comparative experiments revealed that the improved acrylic leak repair material showed no changes in shrinkage due to humidity, temperature variations, or chemical reactions compared to the existing acrylate injection material. In the underwater resistance test, the improved acrylic leak repair material did not show any leakage. Additionally, to assess the environmental impact of the improved acrylic leak repair material, acute fish toxicity tests and acute oral toxicity tests were conducted, and the results showed no mortality and no specific concerns with the test specimens. The experimental results led to the conclusion that the improved acrylic leak repair material is considered to be superior in performance, environmentally safe, and harmless to the human body. Based on various experimental results, it is inferred that the improved acrylic leak repair material is suitable for use as a repair material for cracks in manholes and underground structures compared to the existing acrylate repair material. This study aims to propose valuable data for future technological development by evaluating the applicability of acrylic leak repair materials.

Community development and parasite control (지역사회개발(地域社會開發)과 기생충(寄生虫))

  • Rim, Han-Jong
    • Journal of agricultural medicine and community health
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    • v.1 no.1
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    • pp.10-21
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    • 1976
  • The traditional application of night soil to vegetable gardens and rice paddies results in a most wide spread condition of parasitism, with a variety of helminths found in Korea. In addition to the above fact, the peculiar habit of the consumption of raw vegetables, fish, crustaceans and mammals provides a means of infestations of helminths. During the last sixty years numerous reports were found on the prevalence of helminths amongst the Korean population in different parts of the country, and it was generally recognized that ascariasis, hookworm disease, filariasis, clonorchiasis and paragonimiasis constitute the important helminthic disease in Korea. In practical measures of parasite control activities the main measures are summarized as mass-treatment, night-soil disposal and transmission control. Among the three, the mass-treatment has been commonly applied, however, no reduction of transmission has been obtained by treatment of a population. Therefore, the ultimate eradication of parasites will depend upon the application of comprehensive environmental sanitation measures. The basic environmental measures will be concerned with (a) the safe disposal of human excreta, (b) the provision of adequate and safe water supplies in such a way as to promote a higher standard of personal hygiene in the population, and (c) the prevention of food contamination by faecal material. Additional environmental measures will deal with the improvement of housing and housing hygiene and with general community development. Community development means social and cultural as well as economic development. The control measures on the parasitic endemic diseases, such as clonorchiasis and paragonimiasis are the good examples for community health development in Korea. The control of Clonorchis and Paragonimus infections are theoretically very simple, as the infection can only invade the human body by way of encysted metacercaria which are taken into the body when eating passive intermediate hosts(fishes, crabs and crayfishes). Although prophylactic measures in the case of the infections deal with above merely consist the fishes in cooking or submerging in hot water before eating them, it is exceedingly difficult to carry out such simple measures in face of century old traditions, to which the relatively primitive population clings with great tenacity. There is no one universally applicable method of control. The choice of methods must be dictated by the nature of the environment. the habit and custom of the people. the pattern of transmission and the resources of the country. There must exist a well organized public health infrastructure. Since a control programme is of necessity on a longterm basis and continuity in its implementation is essential. An investigation should be made on the prevalence of the diseases and its relationships to irrigation engineering, freshwater ecology, agricultural methods, hydro-electric schemes, and the development of communities in affected areas. In conclusion, however. the control of clonorchiasis and paragonimiasis in Korea is not an impossible task. A combination of efforts with major emphasis on health education and mass chemotherapy coupled with governmental aid in enforcing legislative public health measures could reduce the diseases. Health education in particular attempts following four things: (a) It supplies a person with enough general knowledge about a disease to make the preventive measures. (b) It makes a person feel sufficiently about the importance of his own health to make him alter his behavior and adopt these preventive measure. (c) It makes him concerned for the health others. (d) It tries to make him feel so strongly about the first three that be supports and even initiates preventive action by the community. Educational efforts should be directed primarily toward school children because it is during the early years that most persons become infected, and also because children are less entrenched in their food habits so that, the educational process should be involved at various levels in successive changes of knowledge, attitude, beha viour, habit and custom of their lives. The most parasitic endemic diseases are related to community diseases. In caring for a sick community. the first stage is to gather epidemiological data, the next is to make inferences from it-to make the community diagnosis. The third is to prescribe community treatment or community health action part of a community health action programme. The community health action is the sum of the steps decided upon to remedy the critical features revealed by the community diagnosis. Action takes various forms; health education is the most important.

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Changes of water Quality During the Seed Production Period of Dark-banded Rockfish Sebastes inermis in Large Scale Tanks (대형 수조에서 볼락 종묘 생산에 따른 수질 환경의 변화)

  • Oh, Sung-Yong;Noh, Choong-Hwan
    • Journal of Aquaculture
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    • v.19 no.1
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    • pp.25-32
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    • 2006
  • An experiment was carried out to investigate changing of water quality during the seed production of dark-banded rockfish Sebastes inermis in large scale tanks. Ten broodstock of dark-banded rockfish were held in three circular tanks (diameter 6.5 m; depth 2 m; water volume 50 ton) each (stocking density $0.061kg/m^3$). During the experiment the temperature ranged from 14.2 to $16.1^{\circ}C$. The fingerlings were 134 with rotifers only during 1 to 9 days after parturition, rotifers with Artemia nauplii during 10 to 20 days after parturition, Artemia nauplii only during 21 to 35 days after parturition, Artemia nauplii with commercial diet during 36 to 80 days after parturition and commercial diet only during 81 to 85 days after parturition. Water quality (dissolved oxygen, pH, $NH_4^+-N,\;NO_2^--N,\;NO_3^--N\;and\;PO_4^{3-}-P$) in rearing tanks measured every 5 days in long term monitoring investigation or every 2 hours in diurnal monitoring investigation. In 85 days after parturition, the body weight of fish grew up to 0.88 f and specific growth rate was 8.0%/day in body weight. In long term monitoring investigation, with the increase of the amount of supplied commercial diet, the concentration of dissolved oxygen (DO) and pH decreased, but the concentration of $NH_4^+-N\;(4.5\;to\;76.3{\mu}M),\;NO_2^--N\;(0.02\;to\;0.06{\mu}M),\;NO_3^--N\;(3.0\;to\;5.9{\mu}M)$, and $PO_4^{3-}-P\;(0.41\;to\;0.59{\mu}M)$ increased. In the diurnal monitoring investigation, the concentration of $NH_4^+-N$ showed great fluctuation and ranged from 3.0 to $9.1{\mu}M$ when fed rotifers, 16.3 to $45.8{\mu}M$ when fed Artemia nauplii and 36.5 to $120.1{\mu}M$ when fed commercial diet. After daily feeding with each of feed, the amount of dissolved inorganic nitrogen (DIN) and phosphorus (P) wastage were 7.0 g and 0.7 g when fed rotifers, 24.7 g and 0.7 g when fed Artemia nauplii and 140.9 g and 2.2 g when 134 commercial diet. The amount of DIN and phosphorous wastage during 134 commercial diet was significantly higher than that of fed rotifer and Artemia nauplii (P<0.05). Results will provide valuable information far water quality management and culture of dark-banded rockfish in commercial seed production systems.