• Title/Summary/Keyword: Clam

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Age and Growth of the Hard Clam, Meretrix lusoria (Bivalvia: Veneridae) on the West Coast of Korea (한국 서해산 백합, Meretrix lusoria의 연령과 성장)

  • Ryu, Dong-Ki;Chung, Ee-Yung;Kim, Yong-Min
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.11 no.4
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    • pp.152-157
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    • 2006
  • Samples of Meretrix lusoria were collected monthly from the tidal flat of Simpo, Puan-gun, Chollabuk-do, west coast of Korea from April 2004 to March 2005. Age of M. lusoria was determined from the rings on the shell. The relationship between shell length and ring radius in each ring group was expressed as a regression line. Therefore, there is a correspondence in each ring formation. Based on the monthly variations in the marginal index (MI') of the shell, it is assumed that the ring of this species was formed once a year during the period of February to April. The relationship between shell length (SL) and shell height (SH; mm) was highly correlated with shell height as the following equation: SH = 0.8103 SL + 0.5145 $(r^2=0.991)$. The shell length (SL) - shell width (SW) relation was also expressed by the following equation: SW = 0.4897 SL + 0.0315 $(r^2=0.976)$. Shell length (SL; mm) and total weight (TW; g) was expressed by the following equation: $TW=2.9195\times10^{-4}\;SL^{2.9547}\;(R^2=0.991)$. Shell length (SL) and shell height (SH; mm) was highly correlated with shell height as the following equation: $SH=0.8103\;SL+0.5145\;(R^2=0.991)$ The shell length (SL) - shell width (SW) relation was also expressed by the following equation: $SW=0.4897\;SL+0.0315\;(R^2=0.976)$. Growth curves for shell length and total weight fitted to the von Bertalanffy's growth curve were expressed respectively as: $SL_t=104.9[l-e^{-0.2235(t+0.7677)}],\;TW_t=280.8[l-e^{-0.2235(t+0.7677)}]^{2.9547}$.

Induction of Intersex and Masculinization of the Equilateral Venus, Gomphina veneriformis (Bivalvia: Veneridae) by Zinc

  • Ju, Sun-Mi;Park, Jung-Jun;Lee, Jung-Sick
    • Animal cells and systems
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    • v.13 no.3
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    • pp.339-344
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    • 2009
  • This study aims to find out the effect of heavy metals, as is the case of EDCs (endocrine disrupting chemicals), on reproductive endocrine disruption of aquatic animals. In the present experiment zinc, which is a heavy metal well known for its androgenous activity, was used. The experimental period was 24 weeks, starting in November during the inactive stage of the clam's reproductive cycle. The experimental groups were composed of one control condition and three zinc exposure conditions (0.64, 1.07, and 1.79 mg/L). The sex ratio (F:M) was 1:1.06 in the control group and 1:1.70 in all the exposed group, illustrating the tendency for higher proportion of males with increases in zinc concentration. Gonad maturity was higher in 1.07, and 1.79 mg/L groups compared to the control group, with higher maturity observed in males than females. Intersex individuals made up 24.7% of the exposed group, while females exhibited a higher ratio than the males with increasing zinc concentration. The results of this study indicate that zinc functions as an androgenic effector on the reproduction of Gomphina veneriformis.

A study on the ecosystem-based resource management system of self-regulatory community fisheries (자율관리 마을어업의 생태계 기반 자원관리시스템 연구)

  • Park, Hee-Won;Zhang, Chang-Ik
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.44 no.4
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    • pp.345-352
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    • 2008
  • A self-regulatory community fisheries management program in Korea is designed to enhance fisheries resources, to protect fishing grounds of self-regulatory communities, and to manage their fisheries resources by their own regulations and knowledge. This study explored an applicable ecosystem-based management plan based on the scientific investigation and analysis. This study suggested objectives, indicators and reference points of the ecosystem-based resource management system which are applicable to selfregulatory community fisheries. The objectives of the management system are to maintain sustainable fisheries production, to maintain optimum fishing intensity, to reduce by-catch, to conserve spawning ground and habitat, to maintain optimum habitat environment, to increase/maintain abundance of prey species, to increase/maintain stock biomass, and to conduct stock enhancement on the basis of scientific assessment. The improved methods for the assessment and management are introduced by demonstrating a self-regulatory fishery which targets on hen clam in Dong-li fishing village in Busan.

Food allergy knowledge, perception of food allergy labeling, and level of dietary practice: A comparison between children with and without food allergy experience

  • Choi, Yongmi;Ju, Seyoung;Chang, Hyeja
    • Nutrition Research and Practice
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    • v.9 no.1
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    • pp.92-98
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    • 2015
  • BACKGROUND/OBJECTIVES: The prevalence of food allergies in Korean children aged 6 to 12 years increased from 10.9% in 1995 to 12.6% in 2012 according to nationwide population studies. Treatment for food allergies is avoidance of allergenic-related foods and epinephrine auto-injector (EPI) for accidental allergic reactions. This study compared knowledge and perception of food allergy labeling and dietary practices of students. SUBJECTS/METHODS: The study was conducted with the fourth to sixth grade students from an elementary school in Yongin. A total of 437 response rate (95%) questionnaires were collected and statistically analyzed. RESULTS: The prevalence of food allergy among respondents was 19.7%, and the most common food allergy-related symptoms were urticaria, followed by itching, vomiting and nausea. Food allergens, other than 12 statutory food allergens, included cheese, cucumber, kiwi, melon, clam, green tea, walnut, grape, apricot and pineapple. Children with and without food allergy experience had a similar level of knowledge on food allergies. Children with food allergy experience thought that food allergy-related labeling on school menus was not clear or informative. CONCLUSION: To understand food allergies and prevent allergic reactions to school foodservice among children, schools must provide more concrete and customized food allergy education.

An analysis of ground supported farm silo with variable thickness (I) -Part I mechanical characteristics of shell with Variable thickness- (지반과 구조물사이의 상호작용을 고려한 변단면 도통형쉘의 해석 (I) -변단면 쉘의 역학적 특성 (I)-)

  • 조진구;조현영
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.31 no.4
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    • pp.58-71
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    • 1989
  • This study aims to develop a computerized program for analysis of the ground-supported cylindrical shell structure with step varied section and to find out its mechanical characteri- stics through application of the developed program to the analysis of a ensiled farm silo as a model structure. The thickness of wall and bottom-plate of farm silo is assumed to be step-varied and its detailed structural dimensions are presented in Tab. 1 and 2. Several numerical case studies show that sectional stresses of the sample structures are largely reduced by adopting "varied section" design technique. And, other major results ob- tained from this study are summarize4 as follows ; 1. The variation of wall-thickness has a great influence on bending stresses of wall. Ho- wever, the larger the relative thickness of bottom-plate is, the smaller the influence is. 2. The magnitude of thickness of projecting toe of bottom-plate has negligible effect on sectional stresses 3. The conventional design methodology, which assumes the bottom edge of wall as clam- ped on ground, is proved to be discarded through the numerical analysis. 4. It is found that the "varied section" design technique should get similar effects as in the case of thick bott6m-plate having uniform thickness. 5. The variation of wall-thickness has a considerable effect on the bending stresses of bo- ttom-plate. Especially, this phenomenon is very remarkable in its projecting toe. In some cases. the negative bending moment may be acted on.

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Studies on the Population Dynamics of Surf Clam, Mactra veneriformis Reeve ( Bivalvia ) in the Coast of Kunsan, Korea I. Growth (군산연안 동죽 개체군의 동태에 관한 연구 I. 성장)

  • 류동기;김용호
    • The Korean Journal of Malacology
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    • v.13 no.2
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    • pp.185-192
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    • 1997
  • 1990젼 3월부터 1991년 2월까지 전라북도 군산시 내초도 연안에 서식하는 동죽의 성장을 조사하였다. 1.조사해역의 연간 수온분포는 2.0-26.3$^{\circ}C$이고, 간석지 온도는 0.7-36.2$^{\circ}C$이었다. 2. 동죽의 패각에 나타나는 윤문은 연 1회 형성되며 윤문 형성시기는 3-4월로 조사되었다. 3. 초륜 형성기간은 9개월(0.75년)로 나타났다. 4. 각장(SL: mm)과 체중(TW: G)간의 관계는 TW=1.090 x $10^{-4}$ S $L^{3.2798}$( $r^{2}$=0.99)이었으며, 각장과 각고(SH:mm)간의 관계는 SH=0.865 SL + 0.250( $r^{2}$=0.99)이고, 각장과 각폭(SW: mm) 간의 관계는 SW=0.599 SL - 0.203 ( $r^{2}$=0.98; 각장 22 mm미만), SW=0.724 SL - 2.796( $r^{2}$=0.91; 각장 22 mm이상)이었다.5. 연령(t)에 대한 각장(S $L_{t}$ )의 Bertalanffy성장식은 $L_{t}$ =51.399(1- $e^{0.585}$8(t+0.064)이고, 연령(t)에 대한 체중 (T $W_{t}$ )의 Bertalanffy성장식은 $W_{t}$ =44.467(1- $e^{0.585}$8(t+0.064)$^{3}$로 나타났다.타났다.

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Prediction of Water Quality and Water Treatment in Saemankeum Lake 1. Effects of Environmental Pollutants on Filtration and Oxygen Consumption of the Marsh clam, Corbicula leana (새만금호의 수질예측과 그에 따른 대책 1. 환경 오염원이 참재첩 ( Corbicula Leana ) 의 여수작용 및 산소소비에 미치는 영향)

  • 정의영;신윤경;최문술
    • The Korean Journal of Malacology
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    • v.13 no.2
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    • pp.203-210
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    • 1997
  • As a prioiminary study on usage of metabolic charateristics of the indicator species for indirect estimation of environmental water quality, effects of environmental pollutants on survival, filtration and oxygen consumption rates in Corbicula aeana were investigated at 17$^{\circ}C$ and $25^{\circ}C$ in 10 day afrer treatmint of pollutants. In case of glucose and complex fertilizer, the survival rates of the clams were 100% without any relation to individual sizes and water temperatures. In small sizes at $25^{\circ}C$, the survival rates of the clams by NH$_{4}$CI concentration were shown 95% at 10 mg/1 and 15mg/1, and 90% at 20mg/1, respectively. But the survival rate was 95%at 20 mg/1 of NH$_{4}$CI concentration in small size at 17$^{\circ}C$. The higher filtration and oxygin consumption rates were shown in small size at higher water timperatures(over $25^{\circ}C$), and generally filtration and oxygen consumption rates decreased with increase of glucose, complex fertilizer and NH$_{4}$CI concentrations, respectively. In general, effects of filtration and oxygen consumption rates at NH$_{4}$CI concentrations were shown slightly larger than those of glucose and complex fertilizer.

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Bacteriological Characteristic of Atrina pectinata and Ruditapes philippinarum under Non-refrigerated and Refrigerated Storage Conditions

  • Kang, Kyoung-Ho;Kim, Byeong-Hak;Kim, Young-Hun
    • The Korean Journal of Malacology
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    • v.24 no.1
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    • pp.25-32
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    • 2008
  • In order to estimate the necessity of refrigerated storage of fresh seafood for short-term storage, and evaluate the effect of refrigerated storage on pen shell Atrina pectinata and clam Ruditapes philippinarum collected from Jang-su of Deukryang Bay and I-mok of Sunchen Bay in South Korea, the counts of coliform, Escherichia coli and total aerobic bacteria in A. pectinata and R. philippinarum under non-refrigerated $(28{\pm}1^{\circ}C)$ and refrigerated storage conditions $(4{\pm}1^{\circ}C)$ were determined. The results indicated that the storage at temperature of $4^{\circ}C$ possessed significant effects on inhibiting bacterial growth in live seafood. And refrigerated storage had different effect on A. pectinata and R. philippinarum. Different species and culture environments significantly influenced the initial and ultima bacteria counts. This study confirmed that refrigerated storage for short-term storage of live seafood was necessary, and indicated that the effect of refrigerated storage was influenced by comprehensive effectors.

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Bilateral Sequential Lung Transplantation for a case with Respiratory Failure due to Lymphagioleiomyomatosis (림프관평활근종증에 의한 호흡부전 환자에서의 순차적양측 폐이식 치험)

  • 성숙환;김주현;김영태;서정욱;유철규;김영환;한성구;심영수;오용석
    • Journal of Chest Surgery
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    • v.33 no.1
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    • pp.88-95
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    • 2000
  • Pulmonary lymphangioleiomyomatosis is a chronic destruct8ive disease of the lung affecting women of childbearing ages which eventually leads to respiratory failure. Lung transplantation is the only conclusive therapeutic measure because this disease responds poorly to other therapies, To date only a few reports in the literature describes the clinical experience of the bilateral sequential lung transplantation of this rare condition. We performed a bilateral sequential lung transplantation on a 32-year-old woman suffering from lymphangioleiomyo-matosisw. The heart-lung block was harvested from a 51-year-old donor. We transplanted the left lung first through the clam-shell incision. As the hemodynamics deteriorated suddenly during the dissection of the right lung the right lung was transplanted under the cardio-pulmonary bypass. Although the patient's lung function was initially satisfactory the patient died of sepsis and subsequent cardiogenic shock at the postoperative 18th day. Autopsy findings showed infection of Candida albicans on the pericardium and the left lung which had been initiated possibly from the left bronchial anastomosis site,. Through detailed review of the clinical course we concluded that lung transplantation could have been performed safely on this disease provided that early diagnosis and proper management or the oppor-tunistic infection have been carried out.

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Influence of Water Temperature and Salinity on Sand Ejection of Manila Clam, Ruditapes philippinarum

  • Kang, Kyoung-Ho;Kim, Jae-Min;Kim, Young-Hun
    • The Korean Journal of Malacology
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    • v.21 no.1
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    • pp.13-17
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    • 2005
  • In this study, the influence of water temperature and salinity on sand ejection of Manila clams, Ruditapes philippinarum, was investigated. The result showed that, under different water temperature, the highest quantity of sand ejection was at $20^{\circ}C$, the value of which was 0.091 g, while the smallest one was only 0.058 g at 0$^{\circ}C$. The highest releasing rate, 95.79%, could be seen in $20^{\circ}C$ group, while $0^{\circ}C$ group was the lowest one, 85.29%. Under different salinity, 30 psu group had the highest value, 0.057 g, and 0 psu (freshwater) group was the lowest one, only 0.026 g. At the same time, the highest releasing rate appeared at 25 psu, which was 90%. 0 psu group was the lowest one in releasing rate, 60.47%. According to these results, we recommend that the clams should be placed into the clear seawater with about 25 psu of salinity at near $20^{\circ}C$ to let the clams perform the self-depuration. Better quality of clams containing less impurity in the aquaculture and commerce could be obtained from this pre-treatment.

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