• 수산경영론집
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• 제34권2호
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• pp.75-90
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• 2003

When we think of fundamental problems of the aquaculture industry, there are several strict conditions, and consequently the aquaculture industry is forced to change. Fish aquaculture has a structural supply surplus in production, aggravation of fishing grounds, stagnant low price due to recent recession, and drastic change of distribution circumstances. It is requested for us to initiate discussion on such issue as “how fish aquaculture establishes its status in the coastal fishery\ulcorner, will fish aquaculture grow in the future\ulcorner, and if so “how it will be restructured\ulcorner” The above issues can be observed in the mariculture of yellow tail, sea scallop and eel. But there have not been studied concerning seabream even though the production is over 30% of the total production of fish aquaculture in resent and it occupied an important status in the fish aquaculture. The objectives of this study is to forecast the future movement of sea bream aquaculture. The first goal of the study is to contribute to managerial and economic studies on the aquaculture industry. The second goal is to identify the factors influencing the competition between production areas and to identify the mechanisms involved. This study will examine the competitive power in individual producing area, its behavior, and its compulsory factors based on case study. Producing areas will be categorized according to following parameters : distance to market and availability of transportation, natural environment, the time of formation of producing areas (leaderㆍfollower), major production items, scale of business and producing areas, degree of organization in production and sales. As a factor in shaping the production area of sea bream aquaculture, natural conditions especially the water temperature is very important. Sea bream shows more active feeding and faster growth in areas located where the water temperature does not go below 13∼14$^{\circ}C$ during the winter. Also fish aquaculture is constrained by the transporting distance. Aquacultured yellowtail is a mass-produced and a mass-distributed item. It is sold a unit of cage and transported by ship. On the other hand, sea bream is sold in small amount in markets and transported by truck; so, the transportation cost is higher than yellow tail. Aquacultured sea bream has different product characteristics due to transport distance. We need to study live fish and fresh fish markets separately. Live fish was the original product form of aquacultured sea bream. Transportation of live fish has more constraints than the transportation of fresh fish. Death rate and distance are highly correlated. In addition, loading capacity of live fish is less than fresh fish. In the case of a 10 ton truck, live fish can only be loaded up to 1.5 tons. But, fresh fish which can be placed in a box can be loaded up to 5 to 6 tons. Because of this characteristics, live fish requires closer location to consumption area than fresh fish. In the consumption markets, the size of fresh fish is mainly 0.8 to 2kg.Live fish usually goes through auction, and quality is graded. Main purchaser comes from many small-sized restaurants, so a relatively small farmer and distributer can sell it. Aquacultured sea bream has been transacted as a fresh fish in GMS ,since 1993 when the price plummeted. Economies of scale works in case of fresh fish. The characteristics of fresh fish is as follows : As a large scale demander, General Merchandise Stores are the main purchasers of sea bream and the size of the fish is around 1.3kg. It mainly goes through negotiation. Aquacultured sea bream has been established as a representative food in General Merchandise Stores. GMS require stable and mass supply, consistent size, and low price. And Distribution of fresh fish is undertook by the large scale distributers, which can satisfy requirements of GMS. The market share in Tokyo Central Wholesale Market shows Mie Pref. is dominating in live fish. And Ehime Pref. is dominating in fresh fish. Ehime Pref. showed remarkable growth in 1990s. At present, the dealings of live fish is decreasing. However, the dealings of fresh fish is increasing in Tokyo Central Wholesale Market. The price of live fish is decreasing more than one of fresh fish. Even though Ehime Pref. has an ideal natural environment for sea bream aquaculture, its entry into sea bream aquaculture was late, because it was located at a further distance to consumers than the competing producing areas. However, Ehime Pref. became the number one producing areas through the sales of fresh fish in the 1990s. The production volume is almost 3 times the production volume of Mie Pref. which is the number two production area. More conversion from yellow tail aquaculture to sea bream aquaculture is taking place in Ehime Pref., because Kagosima Pref. has a better natural environment for yellow tail aquaculture. Transportation is worse than Mie Pref., but this region as a far-flung producing area makes up by increasing the business scale. Ehime Pref. increases the market share for fresh fish by creating demand from GMS. Ehime Pref. has developed market strategies such as a quick return at a small profit, a stable and mass supply and standardization in size. Ehime Pref. increases the market power by the capital of a large scale commission agent. Secondly Mie Pref. is close to markets and composed of small scale farmers. Mie Pref. switched to sea bream aquaculture early, because of the price decrease in aquacultured yellou tail and natural environmental problems. Mie Pref. had not changed until 1993 when the price of the sea bream plummeted. Because it had better natural environment and transportation. Mie Pref. has a suitable water temperature range required for sea bream aquaculture. However, the price of live sea bream continued to decline due to excessive production and economic recession. As a consequence, small scale farmers are faced with a market price below the average production cost in 1993. In such kind of situation, the small-sized and inefficient manager in Mie Pref. was obliged to withdraw from sea bream aquaculture. Kumamoto Pref. is located further from market sites and has an unsuitable nature environmental condition required for sea bream aquaculture. Although Kumamoto Pref. is trying to convert to the puffer fish aquaculture which requires different rearing techniques, aquaculture technique for puffer fish is not established yet.

• 대한기계학회논문집B
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• 제34권8호
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• pp.755-760
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• 2010

본 연구는 승용 디젤엔진의 입자상 물질 배출특성에 관한 것으로써, 엔진에서 배출된 입자상 물질이 배기관 및 후처리장치인 디젤산화촉매와 매연여과장치를 통과할 때의 특성 변화를 파악하기 위하여 후처리장치 각각 전 후단 및 배기관에서 직접 측정하였다. 또한 다양한 엔진회전속도 및 부하조건에서 측정함으로써 입자상 물질 배출 맵을 구축하였으며, 디젤산화촉매 및 매연여과장치의 입자상 물질 저감효과에 대해 평가하였다. 뿐만 아니라 배기재순환율과 연료분사시기를 변경시켜 입자상 물질의 배출특성 변화를 파악하였다. 모든 시험에서 입자상 물질을 5~1000nm 크기까지 측정할 수 있는 DMS500을 이용하였다.

• 한국어류학회지
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• 제34권1호
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• pp.57-63
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• 2022

2016년 4월, 경남 통영시 신봉천에서 채집한 어미 사백어(평균전장 4.6 mm, n=16)를 모래와 돌을 바닥에 깐 실험 수조(60 (L)×30 (W)×30 (H) cm)에 수용하고, 산란행동 및 수정난의 발생과 부화자어의 형태를 관찰하였다. 사백어 어미는 모래 위의 돌 아래에 구멍을 파고 들어가 산란하고, 부화할 때까지 수정난을 보호하는 행동을 보였다. 수정난은 곤봉형(장경 3.2~3.4 mm, 단경 0.6~0.8 mm, n=10)이며 지름이 2~3 cm (원형 또는 타원형)인 난괴를 이루어 돌의 천정에 매달려서 발생하였다. 수온 18~20℃하에서 눈이 생긴 수정난(eyed egg)은 168시간 후에 부화하였다. 부화자어는 투명하며 전장이 4.1~4.4 mm (n=5)이고, 배에는 투명한 난황을 가지고 있었으며 32~33개 (12~13+20)의 근절이 발달해 있었다. 부화 후 3일째, 전장 4.9 mm 자어는 머리의 아래쪽에 입이 열리며 직장이 발달하였다. 전장 난황을 흡수한 전장 5.2 mm 후기자어는 부레 등쪽과 직장 위에 흑색소포가 발달하며 꼬리의 아래 정중선을 따라서 흑색소포가 줄지어 발달하였다.

• Journal of Ginseng Research
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• 제46권1호
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• pp.62-70
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• 2022

Background: Maternal Toxoplasma gondii (T. gondii) infection during pregnancy has been associated with various mental illnesses in the offspring. Ginsenoside Rh2 (GRh2) is a major bioactive compound obtained from ginseng that has an anti-T. gondii effect and attenuates microglial activation through toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) signaling pathway. GRh2 also alleviated tumor-associated or lipopolysaccharide-induced depression. However, the effects and potential mechanisms of GRh2 on depression-like behavior in mouse offspring caused by maternal T. gondii infection during pregnancy have not been investigated. Methods: We examined GRh2 effects on the depression-like behavior in mouse offspring, caused by maternal T. gondii infection during pregnancy, by measuring depression-like behaviors and assaying parameters at the neuronal and molecular level. Results: We showed that GRh2 significantly improved behavioral measures: sucrose consumption, forced swim time and tail suspended immobility time of their offspring. These corresponded with increased tissue concentrations of 5-hydroxytryptamine and dopamine, and attenuated indoleamine 2,3-dioxygenase or enhanced tyrosine hydroxylase expression in the prefrontal cortex. GRh2 ameliorated neuronal damage in the prefrontal cortex. Molecular docking results revealed that GRh2 binds strongly to both TLR4 and high mobility group box 1 (HMGB1). Conclusion: This study demonstrated that GRh2 ameliorated the depression-like behavior in mouse offspring of maternal T. gondii infection during pregnancy by attenuating the excessive activation of microglia and neuroinflammation through the HMGB1/TLR4/NF-κB signaling pathway. It suggests that GRh2 could be considered a potential therapy in preventing and treating psychiatric disorders in the offspring mice of mothers with prenatal exposure to T. gondii infection.

• 한국환경생태학회지
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• 제31권2호
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• pp.152-165
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• 2017

중국 북부와 한국, 러시아 지역에 서식하는 비단털쥐(Tscherskia triton)의 분포를 제외한 생활사, 행동, 생태와 관련된 생물학적 특징에 대해서는 거의 연구된 바 없다. 이에 본 연구는 제주도에서 포획된 개체(n=9)를 대상으로 종 단위 연구의 기본이 되는 번식과 성장 및 발달에 대한 생물학적 정보를 밝히기 위하여 2015년 3월부터 2016년 12월까지 사육실에서 진행되었다. 연구결과, 임신률은 31.7%였고 좁은 케이지에서 보다 넓은 케이지에서 더 높게 나타났다(56.7 vs. 6.7%). 임신기간은 $22{\pm}1.6$일(범위 21-27일), 한배의 산자수(litter size)는 $4.26{\pm}1.37$마리(범위 2-7 마리)였다. 최소이유시기는 $19.2{\pm}1.4$일(범위 18-21일)이었다. 출생 직후 새끼의 체중과 외부형태의 크기는 성별로 차이가 없었으나, 이유시기부터 암수의 머리와 몸통길이(HBL)와 꼬리길이(TL)는 차이가 있는 것으로 나타났다(HBL-weaning, $106.50{\pm}6.02$ vs. $113.34{\pm}4.72mm$, p<0.05; HBL-4 months, $163.93{\pm}5.42$ vs. $182.83{\pm}4.32mm$, p<0.05; TL-4 months, $107.23{\pm}3.25$ vs. $93.95{\pm}2.15mm$, p<0.05). Gompertz 모형과 logistic 모형을 적용하였을 때, 머리-몸통길이에서는 수컷이 암컷보다 최대 성숙 길이가 길었고($164.840{\pm}7.453$ vs. $182.830{\pm}4.319mm$, p<0.0001; $163.936{\pm}5.415$ vs. $182.840{\pm}4.333mm$, p<0.0001), 성장률도 빨랐으나($1.351{\pm}0.065$ vs. $1.435{\pm}0.085$, p<0.05; $2.870{\pm}0.253$ vs. $3.211{\pm}0.635$, p<0.05), 성장곡선의 기울기가 최대가 되는 일령은 암컷보다 조금 늦었다($5.121{\pm}0.318$ vs. $5.520{\pm}0.333$, p<0.05; $6.884{\pm}0.336$ vs. $7.503{\pm}0.453$, p<0.05). 한편 꼬리의 최대길이($105.695{\pm}5.938$ vs. $94.150{\pm}2.507mm$, p<0.001; $111.609{\pm}14.881$ vs. $93.960{\pm}2.150mm$, p<0.05)와 변곡점에서의 길이($60.306{\pm}1.992$ vs. $67.859{\pm}1.330mm$, p<0.0001; $55.714{\pm}7.458$ vs. $46.975{\pm}1.074mm$, p<0.05)는 암컷이 수컷보다 긴 것으로 나타났다. 두 성장모형에서 암수의 체중과 외부형태형질에 대한 성장률은 비교 결과 유사하였다. 이러한 결과는 비단털쥐의 종적 특징을 밝히는데 필요한 자료로 이용될 것이다.

• 농업과학연구
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• 제43권4호
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• pp.595-602
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• 2016

In pigs, individuals in the same pen may show aggressive behavior toward each other, such as tail biting. Such social interactions among pen mates may considerably affect their welfare and performance, both in negative and positive ways. The present study was conducted to investigate social genetic effects on days to 90 kg using data from 12,208 Duroc and Yorkshire pigs that were born between 2008 and 2012. Heritability was estimated using the five following animal models: a basic model with direct heritable effects only (Model 1), a social model with direct and social heritable effects (Model 2), a model accounting for covariance between direct and social heritable effects (Model 3), and two models considering a dilution factor with direct and social heritable effects (Models 4 and 5). The optimal model to represent Duroc pigs was Model 1 which only uses direct heritable effects. Direct heritability (0.21) was higher than total heritability (0.09) and covariance was negative. Model 2 was evaluated as the optimum model for Yorkshire pigs. Yorkshire data showed that total heritability (0.5) was twice as high as direct heritability (0.25) and covariance was positive. Our results suggest that the efficiency of social effects differed among breeding lines. Further research on social effects related to breeds by group size would clarify which is the most efficient selection method that accounts for social genetic effects.

• 한국수산과학회지
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• 제15권4호
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• pp.317-322
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• 1982

꽁치를 통째로 미끼로 하는 다랑어 주낙으로 어획된 다랑어 위속에 들어있는 꽂치 토막의 어체부체별 빈도에서 다랑어의 섭취 습성을 추측하였다. 꽁치 토막을 머리와 꼬리의 유무에 따라 분류하여 꽁치 온마리(A토막) 머리 토막(B토막) 몸통 토막(C토막) 및 꼬리 토막(D토막)으로 구분하고 다랑어 위를 위속에 들어있는 꽁치 토막에 따라 독립적으로 구분하여 A위 , B 위 및 C, D위로 정하고이 호정별로 3개의 소표본을 얻은 다음 소표본마다 그 유의특성을 제거하기 위하여 위와 동-발인 꽁치 토막의 빈도에서 위와 동수만콤의 빈도를 제외한 나머지 빈도에서 위의 호정과 꽁치 토막의 부위와의 관련성을 $X^2$검정하여 다음의 결론을 얻었다. (1) 꽁치의 머리 토막을 삼키고 어획된 다랑어는 먼저 꼬리 토막을 떼어 삼킨 다음 그 꽁치의 머리토막을 삼킨 것으로 인정되는 것이 많다. (2) 꽁치의 머리 토막을 삼킨 다랑어의 조획률은 꽁치 온마리를 삼킨 다랑어의 조획률보다 높아.(3) 꽁치의 머리(A토막과 B토막)를 삼킨 다랑어가 낚시에 낚이지 아니한 것은 아마 꽁치의 꼬리부를 먼저 물어서 그 미끼의 머리가 낚시에서 연도된 것을 삼켰을 것이다.

• Toxicological Research
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• 제26권4호
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• pp.315-320
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• 2010

It has been clinically reported that toluene causes mental depression in humans. However, the detrimental effects of toluene exposure on brain function and the relation between features of mental depression and toluene exposure are poorly understood. This study evaluated depression-like behaviors in adult C57BL/6 mice after administration of toluene, and elucidated the effects of classical antidepressants on the depression-like behaviors. For the estimation of depression-like behaviors, tail suspension test (TST) and forcedswim test (FST) were performed 1, 4 and 16 days after toluene (0~1000 mg/kg bw) treatment. In addition, classical antidepressants such as fluoxetine (FLX, 20 mg/kg bw) and imipramine (IMI, 40 mg/kg bw) were administered 12 h and 1 h before the tests. In the TST and FST, toluene-treated mice exhibited a longer duration of immobility than vehicle-treated mice 1 and 4 days after toluene treatment. The depression-like behaviors were significantly reversed by FLX and IMI. The weight of the adrenal gland and the size of adrenocortical cells were significantly higher in toluene-treated mice compared to vehicle-treated controls. It is suggested that acute toluene exposure of adult mice is sufficiently detrimental to induce depression. In addition, this study has established a mouse model for a depressive state induced by toluene treatment.

• 한국안전학회지
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• 제28권4호
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• pp.14-18
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• 2013

Blades of horizontal axis are nowadays made of composite materials. Generally, composite materials satisfy design provides lower weight and good stiffness, while laminate composites have often damages as like the delamination and cracks at the interface of laminates. The box spar and tail parts of a blade are composed of the CFRP/GFRP hybrid laminate composites. However, delamination and the interfacial crack often occur in the interface of CFRP/GFRP hybrid laminate composites under the mixed mode fracture condition, especially mode I and mode II. Therefore, there is a need for the evaluation of the mixed mode fracture behavior during the delamination of CFRP/GFRP hybrid laminates. This study shows the experimental results for the delamination fracture toughness in CFRP/GFRP hybrid laminate composites. Fracture toughness experiments and estimation are performed by using DMMB(Dissimilar mixed mode bending) specimen. The materials used in the test are a commercial woven type CFRP(Carbon fiber reinforced plastic) prepreg(CF3327) and UD type GFRP(Glass fiber reinforced plastic) prepreg(HD224A). A CFRP/GFRP hybrid laminate composite is composed by the 10 plies CFRP and GFRP prepreg for DMMB. A thickness of CFRP and GFRP layer is 2.5mm and 3.0mm, respectively. Also the fulcrum location which is a loading parameter is changed from 80 to 100mm on the specimen of length 120mm because it defines the ratio of mode I to mode II. In this study, the effects of the fulcrum location are evaluated in the viewpoint of energy release rate in mode I and mode II contribution. The results show that the delamination crack initiates at higher displacement and lower load according to the increase of the fulcrum location ratio. And the variation of the energy release rate for mode I and II contributions for the mode mixity are shown.

• 수산해양기술연구
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• 제36권1호
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• pp.1-11
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• 2000

A low frequency, high power hydroacoustic transducer with 7 tonpilz piston elements assembled in a circular array suitable for marine application, such as the transmission of underwater information and the development of new fisheries resources in the deep sea zone was designed. A modified Mason's model was applied to monitor and to simulate the transducer behavior at each step during the fabrication. The in air, and in water constructed tonpilz transducer was tested experimentally and numerically by changing the size and the type of the material for head, tail and acoustic window. Also, the developed transducer was excited by pulse signals and the received waveform was analyzed. The resonance peaks in the transmitting voltage response(TVR) of a single tonpilz element without housing were observed at 11.33kHz in air and 10.93kHz in air and 10.93 kHz in water, respectively, with the overall electrical-acoustic efficiency of 43.7%. The value of TVR of single tonpilz element with aluminum housing in water was 129.87dB re 1 $\mu$Pa/V at 12.25 kHz with the frequency bandwith of 2.15 kHz and half beam angle of 30.2$^{\circ}$at -3dB.The resonance peaks in the transmitting voltage response of the 7 element circular transducer were observed at 11.50 kHz in air and 11.45 kHz in water, respectively. The value of TVR in water 144.84 dB re 1$\mu$Pa/V at 11.5kHz with the frequency bandwith of 4.25 kHz and the half beam angle of $22.3^{\circ} $ at -3dB.Reasonable agreement between the experimental measurements and the theoretical predictions for the directivity patterns, TVRs and the impedance characteristics of the designed transducer was achieved.