• 한국발생생물학회지:발생과생식
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• 제24권4호
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• pp.307-316
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• 2020

The purpose of this study is to observe the early life history of Korean Lefua costata and use the result as basic taxonomic research data for balitorid fish. The fertilized eggs were light green color with completely circle shape and mean size was 1.21±0.06 mm (n=30). Immediately after hatching, the size of the larvae was 2.81±0.11 mm (n=5) in mean length, with egg yolk. On the 3rd day after hatching, the preflexion larvae had a mean length of 4.64±0.09 mm (n=5), and their mouth was opened to start feeding. On the 8th day after hatching, a mean length of the postflexion larvae was 9.43±0.46 mm (n=5), the distal part of the notochord was bent to 45°, and 16 fin rays were developed on the caudal fin. On the 31st day after hatching, a mean length of juveniles was 22.3±0.85 mm (n=5), and the number of fin rays was the same as that of adult fish with (iv8) dorsal fins and (iii8) anal fins.

• 한국작물학회지
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• 제64권4호
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• pp.323-335
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• 2019

벼 주요재배 품종의 온도 및 일장에 따른 출수반응을 구명한 내용은 다음과 같다. 1. 온도에 따른 출수반응은 일장 12:00, 평균기온 22℃에서 28℃까지의 범위에서 1℃ 상승에 따라 평균 약 3.5일 정도 단축 되는 것을 확인하였으며, 온도가 상승 할수록 그 차이는 감소하는 경향을 보였다. 또한 온도에 따른 출수까지의 소요일수는 생태형별로 뚜렷한 차이를 보이지 못하였다. 2. 14:30과 12:00의 일장조건에 따른 출수까지의 소요일수 차이는 조생종 9.5일, 중생종 18.3일, 중만생종 23.5일로 온도반응과 달리 생태형간 뚜렷한 반응 차이를 보였으며, 일장조건이 짧아질수록 모든 생태형에서 일장반응에 따른 차이가 감소하는 것을 확인하였다. 3. 벼 주요 재배 품종의 화아분화 시점은 32일이었으며, 각 품종별 한계일장은 조생종인 운광, 오대, 고시히카리, 조평은 각각 19:20, 18:14, 18:58, 17:30이었다. 중생종인 대보, 하이아미, 삼덕은 각각 16:08, 16:15 및 16:55이었고, 중만생종인 새누리, 신동진, 추청, 삼광, 일품, 새일미, 황금누리, 동진찰, 일미, 호품, 영호진미는 각각 15:58, 15:56, 16:36, 16:44, 15:35, 16:26, 15:33, 16:20, 16:29, 16:13, 15:41이었다.

• 한국임상수의학회지
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• 제25권6호
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• pp.501-505
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• 2008

Serial ultrasonographic examinations were performed on 9 Miniature Schnauzer bitches from day 15 of gestation until parturition to determine the ultrasonographic measurement of gestational structures. Ovulation was designated the day that plasma progesterone concentration exceeded 4.0 ng/ml (day 0). Extra-fetal structures were measured from day 17 or 18 to 60. Outer uterine diameter (OUD) increased from $6.50{\pm}1.06mm$ ($Mean{\pm}SD$) to $50.89{\pm}5.62mm$, inner chorionic cavity diameter (ICCD) increased from $2.10{\pm}0.15mm$ to $37.15{\pm}4.36mm$, and length of placenta (PL) increased from $7.50 {\pm}1.41mm$ to $40.62{\pm}3.27mm$. OUD and ICCD were significantly and linearly relative to gestational age especially through day 37, whereas PL was not significantly relative to gestational age. Of the extra-fetal structures, ICCD was the most accurate for estimation of gestational age before day 38 of gestation. Fetal structures increased at a linear rate to parturition. Fetal crown-rump length (CRL) increased from $2.55{\pm}0.07mm$ on day 22 to $85.25{\pm}9.89mm$ on day 48. Fetal head diameter (HD) increased from $3.43{\pm}0.64mm$ on day 27 to $25.06{\pm}0.41mm$ on day 63. Fetal body diameter (BD) increased from $ 5.96{\pm}0.84mm$ on day 30 to $43.76{\pm}3.36mm$ on day 63. Of the fetal structures, HD was the most accurate for estimation of gestational age after day 38 to parturition.

• Asian-Australasian Journal of Animal Sciences
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• 제15권3호
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• pp.315-320
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• 2002

Test-day records (n=13677) sampled from 896 ewes in 5-9 (${\mu}$=7.5) monthly test-days were used to estimate genetic and phenotypic parameters of test-day yields, lactation milk yield (TMY), length of the milking period (DAYS) and three measures of persistency of milk yield in Boutsico dairy sheep. Τhe measures of persistency were the slope of the regression line (${\beta}$), the coefficient of variation (CV) of the test-day milk yields and the maximum to average daily milk yield ratio (MA). The estimates of variance components were obtained under a linear mixed model by restricted maximum likelihood. The heritability of test-day yields ranged from 0.15 to 0.24. DAYS were found to be heritable ($h^2$=0.11). Heritability estimates of ${\beta}$, CV and MA were 0.15, 0.13, 0.10, respectively. Selection for maximum lactation yields is expected to result in prolonged milking periods, high rates of decline of yields after peak production, variable test-day yields and higher litter sizes. Selection for flatter lactation curves would reduce lactation yields, increase slightly the length of the milking period and decrease yield variation as well as litter size. The most accurate prediction of TMY was obtained with a linear regression model with the first five test-day records.

• 한국작물학회지
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• 제8권1호
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• pp.111-115
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• 1970

1) 본 실험은 Y.S.A. Gold leaf, oxford 1, Awha Yungzung, Samsun, Maruha, Hatano, 등 8개 품종을 온도와 일장 반응으로 본 것이다. 2) 온도는 저온을 야외(10~$20^{\circ}$) 고온을 온실($20^{\circ}C$~$35^{\circ}C$)에서 맞추었으며 일장은 8.10.12.14로 처리했다. 3) 이를 요약하면 1) 단일 조건에서는 고온보다 저온에서 장일조건에서는 저온보다 고온에서 개화가 촉진되었다. ii) 대체로 고온 장일에서 보다는 저온 단일에서 다소 개화가 촉진 되었다. iii) 그러나 위와 가튼 경향은 품종간에 많은 차이를 볼 수 있다.

• Journal of Plant Biology
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• 제26권4호
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• pp.181-190
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• 1983

Seasonal occurrence of benthic algae and changes of subtidal vegetation were studied for their species composition, diversity and biomass during 1982 and 1983 at several selected sites at Juckdo Island (38$^{\circ}$12'N, 128$^{\circ}$32'E), eastern coast of Korea. Three large brown algae which played a role in change of algal vegetation through their great biomass were investigated with regard to their seasonal growth. Large brown algae such as Undaria pinnatifida, Costaria costata, Laminaria japonica, Agarum cribrosum, Sargassum confusum and S. hornerii constitute the major portion of vegetation in this area throughout the year. Algal vegetation in spring time is characterized by dominance of species U. pinnatifida and C. costata, whereas the summer vegetation by S. confusum and S. hornerii. In autumn large brown algae are shedded and only small algae, such as Chondrus ocellatus and Grateloupia filicina, remain. The vegetation in winter is dominated by the growth of U. pinnatifida and C. costata. Monthly changes in mean length and weight of randomly collected U. pinnatifida, C. costata and S. confusum are as follows; U. pinnatifida occurs from December to June and shows their maximum growth during March (120 cm in length, 201 g/individual in wet weight), its maximum growth rate is 1.4 cm/day, 3.3 g/day in this month. The growth season of C. costata is very similar to U.pinnatifida, but their average maximum length(110 cm) and weight (106 g/ind.) are lower than U. pinnatifida. The greatest growth rate is during March (1.8 cm/day, 2.0g/day). S. confusum is present throughout the year and reaches the maximum growth (102 cm, 63g/ind.) in July. Maximum growth rate (1.5 cm/day, 1.2 g/day) occurs also during this month. U. pinnatifida and C. costata show different months of maximum growth evidently during the two year. This seems to be caused by a considerable damage to the local vegetation followed by heavy storm in February 1983.

• 대한치과교정학회지
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• 제53권3호
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• pp.205-216
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• 2023

Objective: To investigate changes in the immature teeth of Sprague-Dawley rats during orthodontic treatment and to explore the changes in the peri-radicular alveolar bone through micro-computed tomography (CT). Methods: Twenty-five 26-day-old male Sprague-Dawley rats were included. The maxillary left first molar was moved mesially under a continuous force of 30 cN, and the right first molar served as the control. After orthodontic treatment for 7, 14, 21, 28, and 42 days, the root length, tooth volume, and alveolar bone mineral density (BMD) around the mesial root were measured through micro-CT. Results: The immature teeth continued to elongate after application of orthodontic force. The root length on the force side was significantly smaller than that on the control side, whereas the differences in the volume change between both sides were not statistically significant. Alveolar bone in the coronal part of the compression and tension sides showed no difference in BMD between the experimental and control groups. The BMD of the experimental group decreased from day 14 to day 42 in the apical part of the compression side and increased from day 7 to day 42 in the apical part of the tension side. The BMD of the experimental group decreased in the root apex part on day 7. Conclusions: The root length and volume of immature teeth showed continued development under orthodontic forces. Alveolar bone resorption was observed on the compression side, and bone formation was observed on the tension side.

• 한국산림과학회지
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• 제101권3호
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• pp.344-355
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• 2012

임목수확작업시스템 구축과 효율적인 임목수확작업 기술을 보급하기 위해 타워야더 및 스윙야더 등에 의한 전목집재작업시스템과 굴삭기 그래플 등에 의한 단목집재작업시스템의 작업시간 및 공정을 분석하였다. 전체 조사작업시간을 기준으로 분석한 1 cycle당 작업시간은 전목집재작업시스템에서 체인톱에 의한 벌목 46.6초/cycle, 타워야더에 의한 집재 480.6초/cycle, 스윙야더에 의한 집재 287.4초/cycle, 체인톱에 의한 조재 155.14초/cycle로 나타났다. 또 한 단목집재작업시스템에서는 체인톱에 의한 벌목 및 조재 225.65초/cycle, 굴삭기 그래플에 의한 단목집재 4,972초/cycle, 지엽집재 3,143초/cycle로 나타났으며, 바퀴식 미니포워더에 의한 소운재 4,688초/cycle, 굴삭기 그래플 및 소형운재차에 의한 소운재 2,118초/cycle로 나타났다. 전목집재작업시스템의 작업공정에서 체인톱에 의한 평균 벌목공정이 $57.89m^3$/일, 타워야더에 의한 평균 집재공정이 $20.3m^3$/일, 스윙야더에 의한 평균 집재공정이 $31.55m^3$/일, 체인톱에 의한 평균 조재공정이 $20.3m^3$/일로 나타났다. 또한, 단목집재작업시스템의 작업공정에서 체인톱에 의한 평균 벌목 및 조재공정이 $11.96m^3$/일, 굴삭기 그래플에 의한 평균 단목집재공정이 $34.75m^3$/일, 굴삭기 그래플에 의한 평균지엽수집공정이 $37.66m^3$/일, 굴삭기 그래플에 의한 평균 작업로의 개설공정이 73.8 m/일로 나타났으며, 바퀴식 미니포워더와 굴삭기 그래플 및 소형 운재차에 의한 평균 소운재 작업공정이 각각 $15.73m^3$/일과 $65.03m^3$/일로 나타났다.

• 한국발생생물학회지:발생과생식
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• 제22권1호
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• pp.9-18
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• 2018

This study was conducted to investigate the skeletal development of bullhead torrent catfish, Liobagrus obesus larvae and to utilize them as basic data for the taxonomic study of Liobagrus larvae. Skeletal development was observed by being divided into cranium, visceral skeleton, shoulder girdle bone, pelvic girdle bone and vertebra. On the first day after hatching, the pre-larvae had an average total length of 7.92 mm, and a line-shaped parasphenoid ossified in the cranium. In the jaw bone, the dentary supporting the lower jaw and the maxillary supporting the upper jaw were ossified. In the anterior abdominal vertebrae of the vertebra, seven centrums began to ossify and five neural spines ossified simultaneously. On the 3 day after hatching, pre-larvae had an average total length of 8.95 mm, and the prefrontal ossified in cranium. The number of abdominal vertebrae was increased to 14, and three parapophysis developed from the front side. On the 24th day after hatching, post-larvae had an average total length of 15.2 mm and the epural bone ossified in coccyx. The parhypural bone was ossified, and ossification of coccyx and pelvic girdle bone was completed. On the 30th day after hatching, the average total length of the juvenile was 17.8 mm, and the ossification of cranium and visceral skeleton was all completed while the preorbital and three suborbitals were ossified in the orbital region of the cranium.

• 한국응용곤충학회지
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• 제60권2호
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• pp.175-183
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• 2021

식용 및 사료용 곤충으로 활용되는 풀무치에 대한 기초 연구로서 발육 단계별 난소 및 알 발육 특성을 조사하였다. 난소발육을 조사한 결과, 풀무치는 1쌍의 난소와 90개 이상의 무영양실형 난소소관을 가지고 있었다. 난소 길이는 5령 약충보다 성충시기가 더 길었다. 성충 1일째 난소길이는 5령 1일보다 약 2.5배 길었다. 난소 길이는 성충 30일까지 증가한 후, 성충 35일부터 감소되었다. 난소소관 길이는 난소 길이의 1/2 정도로, 역시 난소 길이와 같은 경향을 보였다. 난소 및 난소소관 길이는 체중과 비례적인 상관관계가 있었다. 난소소관의 수는 94-104개로 성충 30일이 총 104개로 가장 많았고 35일부터 감소하였다. 성숙란 수 역시 성충 15일부터 확인할 수 있었고, 성충 30일이 50.6개로 가장 많았다. 수정낭의 크기는 또한 발육 단계에 따라 영향을 받았다. 난괴에서 알을 분리하여 산란 후 일별로 발육 특성을 조사한 결과, 산란 4일부터 무게 및 알의 크기가 급격하게 증가하였고, 산란 후 7일부터는 변화의 폭이 거의 없었다. 산란 7일부터 몸체의 구분이 가능했으며, 산란 10일에 부화되었다. 이상의 결과로 볼 때, 풀무치의 난소발육은 성충 30일이 가장 좋았고, 산란 10일경에 풀무치 1령 약충이 우화하는 것으로 판단된다.