• Journal of Aquaculture
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• v.16 no.2
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• pp.94-98
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• 2003

Effect of temperature (5, 10, 15, 18, 21$^{\circ}C$) on pre-and post-embryonic development of the sea urchin Strongylocentrotus intermedius was studied. The egg, which measured 122.5 ${\mu}{\textrm}{m}$, became globular. At 18$^{\circ}C$, it attained 4 celled stage at 3 hours after fertilization, hatched after 15 hours, 4-armed larval stage after 3 days and 8- armed larval stage after 20 days. The relationships between temperature (WT) and time (1, hour) required for each of the selected developmental stages are: Hatching: 1/t=0.0036WT+0.0088 Pyramid: 1/t=0.0014Wl-0.0016 4- armed: 1/t=0.0009WT-0.0020 6- armed: 1/t=0.0004WT-0.0005 8-armed : 1/t=0.0002WT+0.0002 Biological minimum temperature for the egg and larval development is calculated as 1.61$^{\circ}C$.

• Journal of Aquaculture
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• v.3 no.1
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• pp.1-11
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• 1990

To induce an early spawning, the adult red sea bream, Pagrus major, were exposed to predesignated condition of photoperiod and water temperature during February 21 to June 30, 1988. Spawning began from April 20, a month earlier than that in the natural condition, when the photoperiod and water temperature were controlled at 14L: l0D and $17.0^{\circ}C$, respectively, and the spawning continued until June 15, 1988. There were no particular differences between fish under the controlled condition and those in natural condition in terms of the fertilization rate, surface floating rate, the number of oil glouble and the hatching rate.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.62-62
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• 2003

최근 연안 자원이 급격하게 감소하고 있고 새로운 양식 대상종으로 평가되고 있는 말쥐치의 대량 종묘생산을 위해서는 수정난 대량확보와 자어기 먹이생물 구명 등의 문제점이 해결되어야 한다. 본 연구자들은 우선 호르몬 처리에 의한 산란유도, 조기성숙유도에 의한 조기산란유도 및 수정난 확보방법을 개발하고, 위내용물 분석을 통한 자어의 초기먹이생물을 구명하고자 하였다. 산란유도를 위하여 hCG, LHRH-a 및 hCG+LHRH-a를 다양한 농도로 처리하여 실험한 결과 모든 실험구에서 67~76%의 수정률을 나타내었으나, 대량의 성숙란을 얻지는 못하였다. 따라서 본 종의 산란특성이 다회성인 점을 감안한다면 500 g 전후의 친어 200~300마리를 1개의 수조에 수용하여 자연산란된 수정란을 수거하는 것이 좋을 것으로 판단되었다. 평균 450 g 정도의 말쥐치 친어를 12월부터 6개월동안 천천히 수온을 상승시켜 자연산란을 유도한 결과, 자연산란기 (6월)보다 2개월 빠른 4월 15일(17$^{\circ}C$로 가온한 지 15일)에 첫 산란이 이루어졌고 1개월간 지속되었다. 초기 사육환경을 구명하기 위한 실험에서는 일반적으로 해산어 종묘 생산에 이용하는 클로렐라＋rotifer 실험군이 클로렐라 단독, 규조류 단독, 규조＋rotifer, 녹조＋copepods등이 번식된 환경보다 생존율에 있어 월등히 높은 결과를 나타내었다. 위 내용물 분석에 의한 사육기간 중 섭식한 주요 먹이생물종은 부화 후 5일부터 20일째까지는 rotifer egg, 부화 10일째는 rotifer egg와 small rotifer, 부화 20일째는 rotifer, Artemia sp., copepods, 부화 25일째부터는 copepods였다. 초기성장은 부화직후 전장 1.95 mm였던 것이 10일째는 2.96 mm, 20일째는 3.89 mm, 30일째는 12.9 mm, 50일째는 35.1 mm를 나타내었다. 그러나 말쥐치 자ㆍ치어가 성장함에 따라 발생하는 지속적인 폐사와 종묘의 수송시 발생하는 폐사를 줄일 수 있는 방법이 추후에 해결되어야 할 것으로 사료된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.5
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• pp.390-399
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• 1988

A conventional BTC has the merit of real time processing and simple computation, but has the problem that its compression rate is low. In this paper, a modified BTC using the Quad Tree which is frequently used in binary image is proposed. The method results in the low compression rate by decreasing the total number of subblocks by mean of making the size of a subblock large in the small variation area of graty level and the size af a subblock small in the large variation area of gary level. For the effective transmission of bit plane, the Huffman run-lengh code for the large size of a subblock and the lookup table for tha small size of a subblock are used. The proposed BTC method show the result of coding 256 level image at the average data rate of about 0.8 bit/pixel.

• Journal of Aquaculture
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• v.13 no.4
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• pp.277-284
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• 2000

Rabbitfish hatchlings were given a mixed food of rotifers (Brachionus rotundiformis) and trochophore larvae of oyster. Only the oyster-trochophore larvae were found in the gut of 62-h old fish larvae. The fish larvae, fed on rotifer and ciliate alone did not survive. However, their survival increased to 3.3 % on the 10th day after hatching, when trochophore was supplemented. Corresponding with the accelerated growth, the number of rotifers consumed increased from 11 in a 5-day old fish to 165 in a IS-day old fish. In a field ecosystem containing live diatom, Nannochloropsis oculata, rotifers and copepods, fish larvae were shocked and the oyster's trochophore larvae were fed from 2 to 7 days after hatching. A total of 76,000 seedling were produced after 50 days of hatching with 12.7 % survival. Mean total length and body weight were 65.6 mm and 3.4 g, respectively. Growth of body length (BL), body height (BH), body weight (BW) and head length (HL) as a function of the total length (TL) showed regressional relationships as follows; BL=0.8565 TL+0.0852 ($t^2$=0.9996); BH=0.3207 TL - 0.5052 (($t^2$=0.9641) BW=0.0652 TL2.3508 (($t^2$=0.9925); HL=0.2595 TL - 0.1898 (($t^2$=0.9901)

• Journal of Aquaculture
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• v.18 no.2
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• pp.107-114
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• 2005

Clownfish are important and very popular fish in the ornamental aquarium industry. Demand for the fish is increasing dramatically. The present study was conducted to verify methods of broodstock management, patterns of spawning, rates of egg hatching and estimates of larval growth fur the saddleback clownfish, Amphiprion polymnus. Spawning occurred 8 times between August 2002 to June 2004 with 2 females and 1 male participating. Fertilized eggs were separated by an adhesive matrix and were oval in shape. The eggs were $2.46{\pm}0.13mm$ in size as measured along the longest axis. The percentage of fertilized eggs was 96.7%. Hatching was observed seven days post-spawning and hatching rate was 85.5%. The sizes of the newly-hatched larvae were $4.58{\pm}0.21mm$ TL (total length). Larvae had an open mouth and anus, and an oval yolk sac. At the 1 st day after hatching, the sizes of the larvae were $4.90{\pm}0.35mm$ TL. The larvae began to eat rotifers after complete yolk absorption. On the 5th day post-hatch, larvae were $5.88{\pm}0.31mm$ TL with complete fins and the survival rate was 48.6%. At 8 days after hatching, a band began to appear on head and back of the larvae indicating the beginning of metamorphosis. Metamorphosis was completed at an average TL of $15.00{\pm}2.12mm$ on the 23rd day after hatching. By the 45th day after hatching, juveniles averaged $22.76{\pm}3.22mm$ TL and survival rate was 28.4%.

• Clinical and Experimental Reproductive Medicine
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• v.35 no.1
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• pp.49-60
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• 2008

Objective: This study was carried out to investigate the effects of 3-dimensional co-culture of human endometrial cells decidualized with progesterone and TGF-${\beta}1$ on the development of 2-cell mouse embryos. Methods: Stromal and epithelial cells isolated from human endometrial tissue were immunostained for cytokeratin and vimentin. Expression of TGF-${\beta}1$, its receptor-1, -2, integrin-${\beta}3$ and prolactin in mono or co-culture according to three different hormone conditions was investigated by RT-PCR. Differential staining was used to investigate the number of ICM and trophectoderm of hatched mouse blastocysts in different three conditions. Results: The immunohistochemical study was positive for cytokeratin or vimentin and confirmed that epithelial and stromal cells were isolated from endometrial tissue successfully. In co-culture, TGF-${\beta}1$, its receptor-1, integrin-${\beta}3$ and prolactin except TGF-${\beta}1$-r2 were expressed in progesterone dominant condition. The hatching and attaching rate were higher in the co-culture with decidualized cells (p<0.05). However, we observed that lots of the incomplete hatched blactocysts attached on non-decidualized cells. The ICM number of hatched mouse blastocysts was higher in co-culture with decidualized and non decidualized cells than media only culture (p<0.05). The trophectoderm number of hatched blastocyst was higher in the co-culture with decidualized cells than non-decidualized cells or media only culture (p<0.05). Conclusion: The administration of progesterone, estrogen and TGF-$\beta$ could induce decidualization of stromal and epithelial cells isolated from human endometrial tissue using 3-dimensional co-culture, and the decidualization of human endometrial cells could increase the hatching and attaching rate of 2-cell mouse embryos.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.3
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• pp.233-237
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• 2000

The complete postembryonic development of nauplius stages of Paramphiascella vararensis T. Scotf (Copepoda: Harpacticoida) is described and illustrated based on specimens cultured in laboratory. The nauplii of P. vararensis feed on powder of a green algae, Ulva perusa. This species is metamorphosed to the stages of nauplius. Development from the nauplius stage to the nauplius stage take about 12 days under culture conditions of 33-34 ppt of salinity, 22-23$^{\circ}$C of temperature and feed on the algal powder. In the nauplius stages of P. vararensis, the rudiment of maxillule appeares at the third nauplius stage, and maxilla appeares at the fifth nauplius stage.

• Animal Systematics, Evolution and Diversity
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• v.5 no.2
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• pp.89-105
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• 1989

농게(Ura arcuata) (달랑게과, 달랑게아과) 의 유생을 부화에서부터 첫 번째 게기까지 수온 $25^{\circ}C$ , 염분농도 33.3$\textperthousand$의 해수에서 사육하고, 각 유생기이 형태적인 특징을 기술 및 도식하였다. 이 종은 5기의 zoea와 1기의 megalopa 유생을 거쳐 첫 번째 게기로 변태하였다. 제 1 zoea 유생기는 제 1 소악의 내지에 4개의 말단강모와 제 2 악각의 기절과 내지에 각각 3개의 우상강모와 0, 0, 5 강모식을 가지고 촉각은 B형이었다. 이러한 특징들은 이미 보고된 같은 과의 유생들의 특징들과 잘 일치하고 있다.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.10a
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• pp.287-287
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• 2000

전북 식도 연안 정치망에서 1996년 6월에서 11월 사이 월별로 채집된 멸치 유어 이석의 일륜과 그 폭을 광학현미경과 주사전자현미경으로 관찰하여 산란기를 추정하고, 일일 성장률을 역추산하여 산란기에 따른 일일 성장률을 비교 분석하였다. 시상면 (sagittal plane)을 지나는 이석에는 부화 성장 정지선(hatch check)이 형성되었고, 그 외부를 둘러싼 난황 자어기에 형성된 것으로 추정되는 평균 4개의 불분명한 미세성장선이 관찰되었으며, 난황흡수성장정지선(yolk-absorption mark)이후에는 비교적 명확한 일륜이 형성되었다. (중략)