• Journal of Sericultural and Entomological Science
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• v.32 no.1
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• pp.17-30
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• 1990

A 6${\times}$4 top-cross set was made from the ten silkworm parental lines selected by the first principal component scores. They were also analysed for the relationship between the combining ability and the first principal component score. The highest general combining ability effects were detected in the parental lines of Japanese, N39 and chinese, C46, for the most quantitative characters in the study. The first principal component score of factors related to silk productivity in the parents was significantly and positively correlated to the general combining ability of the twelve characters such as cocoon yield, cocoon weight, cocoon shell weight, cocoon shell percentage, duration of the 5th instar larvae, total larval period, length of a bave, weight of a have, non-breaking length of a bave, non-breaking weight of a have, raw silk percentage, and neatness. Similarity distance (D$^2$) was related to the specific combining ability of the characters such as cocoon yield, non-breaking length of a bave, non-breaking weight of a have, non-breaking ratio of a bave, raw silk percentage, neatness. From the results, it is possible to predict the general combining ability effects by the principal component scores for the 12 characters of the parents related to silk productivity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.4
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• pp.529-534
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• 1998

Age and growth of the yellow goosefish, Lophius litulon, were studied using samples collected from the southwestern waters of Korea. Vertebrae of the fish had relatively clear annuli on their surface. The opaque zone of vertebrae was formed once a year between March and April. The oldest fish observed in this study was 8 years old for females and 5 years old for males. The relationship between the radius (R) of vertebral centrum and total length (L) was as follows: L=12.7+4.8R for females and L=9.8+5.6R for males. The relationship between total length and body weight (W) was as follows : $W=0.0089L^{3.0311}$ for females and $W=0.0329L^{2.7752}$ for males. Growth in length of the fish was expressed by the von Bertalanffy's equation as $L_t=127.60(1-e^{-0.1228(t+0.3851)})$ for females and $L_t=82.23(1-e^{-0.1832(t+0.6431)})$ for males.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.7
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• pp.922-925
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• 2015

This study was conducted to estimate the genetic parameters for pork belly traits and muscles in Yorkshire pigs. Each pork belly was cut into nine parts perpendicular to the thoracic vertebrae (6th to 14th). Traits of belly muscles including the deep pectoral, latissimus dorsi, cutaneous trunci, rectus abdominis, external and internal abdominal oblique from 382 purebred pigs were recorded and analyzed using SAS Package (9.1) and Derivative-free restricted maximum likelihood methods. Heritability estimates for belly traits ranged from 0.27 to 0.49, while they were 0.12 to 0.66 for belly muscles. Moderate to high heritability estimates were noted in belly weight (0.33), belly length (0.28), and belly width (0.49). In belly muscles, the latissimus dorsi and deep pectoral, which are located only in the 6th to 9th vertebrae sections, were found to have heritability estimates ranging from 0.21 to 0.29 and 0.23 to 0.35, respectively. Strong heritability estimates were observed in the 7th to 13th sections of cutaneous trunci muscle ranging from 0.42 to 0.66. Genetic correlations of latissimus dorsi m. with belly length were positive (0.50), while cutaneous trunci m. with belly weight also revealed a positive relationship that ranged from 0.35 to 0.47. The estimated genetic parameters indicate that belly weight can be improved by genetic selection. Differences in the levels of heritability occurred among various parameters of Yorkshire pork belly, which should be considered when performing selection to improve pork belly quality. Moreover, these results can provide valuable information that can be used as the basis for further investigations to improve pork belly.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.757-761
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• 1995

The relationship between the molecular structure of rice starch and the texture of cooked rice was investigated using hot-water soluble rice starch. The structure of hot-water soluble starch bound amylose which was composed of small molecular weight and amylopectin which was composed of chain length of $\overline{DP}\;10{\sim}20$, and the average composition of amylose : amylopectin was 7 : 3. The molecular weight of amylose was the smaller and super long chain of amylopectin was the fewer, the extractable ratio of hot-water soluble rice starch was the higher. And hot-water solubility of rice starch be responsible for molecular structure of starch. On the texture of cooked rice, the extractable ratio of hot-water soluble rice starch was the higher, the hardness was the lower and the adhesiveness was the higher. The results suggest that the molecular structure of rice starch could be responsible for the texture of cooked rice.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.2
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• pp.113-120
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• 2022

The purpose of this study is to provide information about annual variations in catch size and changes in reproductive biology in the common octopus, Octopus vulgaris, a commercially important species in Jeju Island. Samples were collected from coastal waters of Jeju Island, Korea by coastal trap fishery from January to November 2021. Octopus vulgaris have been decreasing in this region since 1984. The mantle length (ML) ranged from 4.5 to 17.8 cm and body weight (BW) ranged form 88.5 to 2,657.5 g. A χ²-test revealed that the number of males was significantly greater than females (χ² = 32.712, df = 10, P<0.05). Mature females were found from January to July and male occurred January to August. The gonadosomatic index value was higher from July to August than other months. The relationship between mantle length and body weight was BW = 2.4527ML^2.3139 (female) and BW = 2.6785ML^2.3159 (male). At 50% group maturity, female and male average weight was estimated to be 554.7 g and 330.6 g, respectively.

• Korean Journal of Poultry Science
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• v.49 no.3
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• pp.145-156
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• 2022

The effect of paternal telomere length on reproductive performance, relationship between paternal and offspring telomere length, and association between paternal telomere length and offspring production performance were investigated in Korean native chickens. Using 22 paternal chickens and 329 offspring, the paternal reproductive performance such as fertility, embryo mortality, and hatchability, as well as the offspring production performance such as survival rate, body weight, and weight gain were analyzed. Telomere length was analyzed through quantitative fluorescence in situ hybridization using lymphocytes. No significant differences were observed in fertility, embryo mortality, and hatchability between paternal chicken telomere lengths (P<0.05). These results indicate that paternal telomere length had a weak negative correlation with fertility and embryonic death rate but a weak positive correlation with hatchability. The correlation coefficient between paternal telomere length and offspring survival rate was r=0.17 (P>0.05). The group of offspring with long paternal telomeres showed relatively poor growth performance. Moreover, a significant negative correlation was estimated between paternal telomere length and offspring growth performance (P<0.05). The correlation coefficient between paternal and offspring telomere lengths was r=0.075 (P>0.05). In conclusion, there was a weak association between paternal telomere length and reproductive performance, offspring survival rate, and offspring telomere length, respectively. However, paternal telomere length and offspring growth performance showed a negative relationship. Such results could be due to the re-extension of telomere length by telomere reprogramming in the early embryonic stage and the different degree of telomere shortening between individuals with increasing age after birth.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.2
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• pp.245-250
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• 1997

Highly significant correlation (p < 0.001) was found between body weight and chest circumference of the local Katjang and cross-bred (local Katjang ♀ ${\times}$ German Fawn ♂ bucks under study. Increase in body length, chest circumference, depth of chest and height at withers (p < 0.001) reflected significantly the increase in body weight of the bucks. At the same age the cross-breds were bigger than the indigenous breed. No significant correlation was detected between body weight and scrotal circumference, or the latter with sperm counts in both buck types under study. However, the fluid portion of the semen increased in acidity and volume, the latter being significant (P < 0.01) in the local Katjangs, with increase in scrotal circumference. Although the effects of body condition on buck libido of both groups were not significant, the reaction time taken to mount the teaser females were significantly diminished (p < 0.001) with better body condition, at least in the local Katjangs. The reaction time gad an inverse, though not necessarily significant, relationship with semen characteristics such as volume, pH (in local Katjangs, p < 0.05), concentration, color (in cross-breds, p < 0.05), agglutination and mass movements in both phenotypes.

• Journal of the military operations research society of Korea
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• v.3 no.1
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• pp.83-96
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• 1977

The combustion chamber and nozzle of an end burning, small spherical rocket is designed. A spherical external shape has a number of advantages such as fixed center-of-gravity and minimum aerodynamic precession torques during flight and a better mass distribution for gyro-stabilization as contrasted to a conventional ogive rocket shape. It is shown that the cross-sectional variation of the end burning solid propellant with length is an exponential geometry to provide a constant thrust-weight ratio of the rocket device during the propellant burning period, and that the factors which affect the attainment of the constant relationship of thrust to weight in the design are the initial propellant area, initial weight of the rocket and propellant density. The measurement of the transient thrust in the ground static test using black powder propellant supports the predicted results. A wind tunnel having a $30{\times}30{\times}75cm$ test section and Mach number 0.11 is constructed, and a simple balance-type device is designed for the measurement of the drag of a spinning sphere. The experimental results indicate that the. spinning has no effect on the magnitude of the drag up to the Reynolds number $3{\times}10^5$. Numerical computation of the flight trajectories for various launching angles is presented, and the gyro-stabilization of spinning sphere is discussed.

• Journal of The Korean Society of Grassland and Forage Science
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• v.9 no.1
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• pp.15-19
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• 1989

This experiment was carried out in order to know the changes in dry matter production of the 2nd cutting by the times of established pasture and its relation with morphological and structural characters of orchardgrass sward. Experimental pasture was established by the times of year, from 1 year to 7 year, 1986 through 1980, alternately. The results were summarizedas follows: 1. The population density of the 2nd cutting was extremely decreased by the times of established year. 2. The dry weight of $plantsW)$ was positively significant correlations with plant length(PL), number of tillers per plant (NT/pl.) and the dry weight of plant(DW/pl.). 3. The highest value of the dry weight of plants(DW) was obtained at 7 year old pasture. 4. The pasture productivity of 7 year old pasture was resulted by the increases of regrowth capacity, yield components and structural characters of the 2nd cutting. 5 . Relationship between morphological and structural characters concerned vegetational structure of the 2nd cutting were changeable year by year.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.4 no.1
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• pp.7-16
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• 1971

This paper deals with the numbers of vertebrae, gill rakers and relative growth of the Pacific saury, Cololabis saira along the eastern coast of Korea in May, July and December 1970. About 90 percent of the total fish population possessed 64-66 vertebrae with the mean of 64.80 and the mode of 65. The number of gill rakers varied from 33 to 44 in December with the mean of 37.08. With regard to the number of vertebrae and gill rakers of the medium (26.0-28.0 cm in fork length) and large (30.0-31.0 cm in fork length) sized groups, there are similarities between the northbound modium sized group and the southbound large sized one, and also between the southbound medium and southbound large sized groups. Although no correlation was found between the numbers of vertebrae and gill rakers, in December the number of vertebrae of the large sized group exceeded that of the medium sized group, and on the other hand the number of gill rakers of the large sized group was fewer than that of the meduim sized one. There was a tendency of decreasing in ratio of the head length to the fork length as the latter increased, The relationships between the fork length and the head length varied depending on the northbound and southbound migration of the fish. The same tendency was also seen in the relationship between the fork length and the body weight. The body weight increased from July to December (from medium to largo sized group) showed more than twice than that from December to the following July (from medium to large sized group). The coefficient of fatness remained constant in December, but a distinct variation was found between the medium and large sized groups in July, corresponding to the spawning sea-son of the fish. Relatively higher coefficient was found in December as compared to that found in July.