• Ocean and Polar Research
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• v.28 no.3
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• pp.237-243
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• 2006

The ages of sandfish, Arctoscopus japoninis sampled from the eastern sea of Korea, were determined by the transverse section method of otoliths. Ages were assigned to every individual according to the number of opaque zones, and then fitted to the von Bertalanffy growth equation. Estimated equations were $L_t=25.90(1-e^{-0.2976(t+0.4447)})$ for females and $L_t=21.38(1-e^{-0.2917(t+1.2087)})$ for males, where t is age (year) and $L_t$, is body length (mm) at age t. These two equations were significantly different and the body length of females calculated from the equation was larger than that of males except at 1 year old.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.333-338
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• 2006

The purpose of the present study was to clarify the sexual difference of the Heath-Carter somatotype related variables in boys and girls from 7 through 19 years of age. In the study design, the subjects and the methods were used by the cross-sectional investigation. The subjects participated in this study were 7 through 19 years of age who belonged to typical primary, junior, senior high school and college students, and about 250 males and 250 females in each group and both sexes. Therefore, the total subjects were 3,046 males and 2,984 females. All subjects of this study lived in Pusan metropolitan city, Korea. Somatotype was calculated by the Heath-Carter's anthropometric somatotype method, In this study, in attaiment rates of sum of 4 sites skinfold and endomorphy growth, girls were significantly higher than boys in all ages intervals except through 13 years of aged groups, respectively. In attainment rates of humerus and femur breadths growth, boys were significantly higher than girls in all ages interval except 13 through 15 years of aged groups, respectively. In attainment rate of arm circumference growth, boys were significantly higher than girls in all ages interval except 7 years of aged group. In attainment rate of calf circumference growth, boys were significantly higher than girls in all ages interal except 15years of aged group. In attainment rate of ectomorphy growth, boys were significantly higher than girls in all aged interal except 8 thorough 12 years of aged groups. This results suggests the urgent necessity of developing systematic and sperate progams to treat such sexual difference in boys and girls.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.327-327
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• 2017

The effect of different seedling ages and transplanting times on the growth and yield of Indica ${\times}$ Japonica rice for noodle processing was evaluated to develop a high yielding cultivation technology for increasing the competition against the imported foreign rice. Four seedling ages (10-, 20-, 30- and 33-day old) of two Indica ${\times}$ Japonica rice cultivars (cvs. Saemimyeon and Palbangmi) and three transplanting dates (May 20, May 30 and June 9) were used in the study. Our results showed that the growth and rice yield of the two cultivars were significantly affected by the different seedling ages and transplanting times. Dry matter production at the panicle heading of the two rice cultivars were generally higher in the 30-day old seedling than the other seedling age treatments and then gradually decreased as the transplanting time was delayed from May 20 to June 9. Similar high panicle number per square meter were recorded at the 30-day old seedling between May 20-May 30 transplanting times. In contrast, other yield parameters that includes spikelet number per panicle, 1,000-brown rice weight, and ripened grain ratio (except for the June 9 transplanting time of Palbangmi) were not significantly affected. The milled rice yield of Saemimyeon was higher than that of the Palbangmi regardless of seedling ages and it was also the highest at the 30-day old seedling with four seedling ages. The milled rice yield of Saemimyeon was only slightly decreased as the transplanting time was delayed from the May 20 to June 9 but Palbangmi had a significantly lower milled rice yield at June 9 transplanting due to the low ripened grain ratio. The result indicates that the most suitable seedling age for the cultivars tested was at 30-day old seedling for noodle processing rice and recommended transplanting times were between May 20 and May 30 for the high rice yield in the Yeongnam plain area.

• Clinical and Experimental Reproductive Medicine
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• v.13 no.2
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• pp.195-200
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• 1986

In order to know when the cumulus cells of mouse follicles get ability to expand in vitro, the oocyte cumulus complexes obtained from different growing ages of mice were cultured in the medium containing HCG and their rate of expansion were observed and at the same time their maturation rate was examined. The growth of follicles was also checked by histological method. It was impossible to isolate the oocyte-cumulus complexes from 13 or 15 days old mouse ovaries. The oocyte-cumulus complexes collected from 17 days old mouse were partially induced to expanded by HCG, and from 19 days, most of the complexes were induced to full expansion. The rate of cumulus cell expansion by HCG and the oocyte maturation increased steadly during the growing ages to adult. Thus, the time for follicles to get competence for expansion and maturation seems to be closely related. Antral follicles were appeared from 17 days old mice and Graafian follicles were seen from 21 days old mice. The competence for cumulus expansion increased during follicle growth up to 21 days old mice.

• Journal of Animal Science and Technology
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• v.44 no.2
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• pp.165-170
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• 2002

Mature weight (A) and rate of maturing (k) estimated by nonlinear regression were studied to determine the optimum age range over which the estimate of growth curve parameters can be estimated. The weight-age data from 1,133 Hanwoo bulls at Hanwoo Improvement Center of N.A.C.F. were used to fit the growth curve using Gompertz model. All available weight data from birth to the specific age of months were used for the estimation of parameters: the six specific ages used were 12, 14, 16, 18, 20 22 and 24 months of age. The mean estimates of mature weight (A) were 966.5, 1,255.9, 1,126.2, 916.5, 842.2, 780.9 and 767.0kg for ages 12 through 24 months, respectively. The mean estimates of mature weight (A) to 22 and 24 months of age were not different from each other. However, they were different from the estimates based on the data to other ages. Mean estimates of rate of maturing (k) were 3.362, 3.595, 3.536, 3.421, 3.403, 3.409 and 3.411 for ages 12 through 24 months, respectively. The mean estimates of maturing rate (k) for ages 18 through 24 months of age were not significantly different from each other. However, they were different from the estimates based on the data to other ages. Correlations among estimates of A at various ages showed the highest value of 0.93 between 22 and 24 months. Correlations among estimates of k at various ages were highest ranging from 0.91 to 0.99 among 18 to 24 months. The correlations between A and k were positive and tended to decrease with the increase of the age from 0.84 for the age of 12 months to 0.10 for the age of 24 months. Thus, the estimates of growth curve parameters, A and k, suitable for genetic studies can be derived from accumulated Hanwoo bulls after 22 months of age.

• Korean Journal of Health Education and Promotion
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• v.14 no.1
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• pp.161-172
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• 1997

In order to assess the physical growth and development, and nutritional status of primary, middle and high school students in the city of Seoul, physiques of 4, 041 persons(Male : 2, 096, Female: 1, 945) were measured from March 1 to July 31 in 1995 and variouis physical and nutritional indices, maximum growth age related to them were calculated. The results are as follows: 1. Physical Growth and Development The growth of body height showed straight linear development among male in the ages 7~16 and among female 7~14, and after that showed slower development. The age of cross over between two sexes was between 11.5 to 12.5 years of age. The maximum growth age was between 11 and 12 years of age(7.28cm) in male and between 11 aqnd 12 years of age(9.77cm) in female. In terms of body weight, it also showed straight linear development among male in the ages 7~16 and among female 7~14, and after that showed slower development. The maximum growth age was between 11 and 12 years of age(7.64kg) in male and between 11 and 12 years of age(8.l9kg) in female. In terms of chest girth, it showed two step development among male in the age of 7~13 and 13~17, and among female in the age of 7~14 and 14~17. The age of cross over between two sexes was 11 and 12 years of age. In terms of sitting height, it showed two step development in the age of 7~14 and 14~17 of both sexes and the age of cross over between two sexes was between 10.5 to 14.5 years of age. The maximum growth age was between 11 and 12 years of age(3.64cm) in male and between 11 and 12 years of age(5.98cm) in female. 2. Maximum Growth Age of Physical Growth and Development In body height, MGA was 10.59 for male and 10.34 for female which showed that MGA for both sexes appeared in similar periods. In body weight, MGA was 10.30 for male and 10.30 for female which showed that MGA for both sexes appeared in similar periods. In chest-girth, MGA was 14.74 for male and 11.60 for female which showed that MGA for female appeared about 3 years earlier than for male. In sitting height, MGA was 11.69 for male and 11.38 for female which showed that MGA for both sexes appeared in similar periods. Maximum growth ages of physiques appeared in order of body height 〉 body weight 〉 sitting height 〉 chest-girth.

• Journal of Korean Society of Forest Science
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• v.95 no.1
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• pp.131-138
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• 2006

This study was conducted to assess the diameter growth patterns of Quercus mongolica and Quercus variabilis dominant species in natural deciduous forests in Korea. The diameter growth data were collected from 83 destructively sample trees for stem analysis in Gangwon-Do region. The relationship between diameter growth and 14 tree measurements was also analyzed. The average diameter growth rate of dominant trees for both species increased until ages of 15-20 years, and exhibited generally constant trend for subsequent ages. The diameter growth rate of both species ranged from 0.09-0.83 cm/yr across the all ages. Average annual diameter growth for last 5 measurement years was 0.28 cm/yr for Quercus mongolica and 0.27cm/yr for Quercus variabilis. The observed growth rate decreased with decreasing crown class. The difference between diameter growth rates for different crown classes was only statistically significant (p<0.0001) for Quercus mongolica. Pearson correlation coefficient between the diameter growth rate decreased with relative diameter (r=0.64), relative height (r=0.61), exposed crown area (r=0.58) and total crown area (r=0.56) for Quercus mongolica. For Quercus variabilis, Pearson correlation coefficient decreased with dbh (r=0.57), crown width (r=0.55), age (r=0.39), competition index (r=-0.39), and height (r=0.35).

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.377-386
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• 2008

The growth performance of Eastern white pine (Pinus storbus L.) was studied with six provenances in four plantations. All growth performances were significantly different among provenances and plantations. The most outstanding source in volume growth at age 39 is North Carolina in all plantations and this trends had been started from four years old seedlings. In plantations, the growth is best in ChunCheon plantation while that is worst in GunPo plantation. The Effect of plantations was thought to be larger than that of provenances growth of P. strobus. A pattern of growth by ages was different by among plantations and even ate age about 40, the growth was still vigorous. Annual precipitation, foggy days, altitude and sand contents in soil are positively correlated with growth and the correlations between by ages were very high.

• Animal Bioscience
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• v.34 no.12
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• pp.1886-1894
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• 2021

Objective: Growth hormone (GH) and insulin-like growth factor I (IGF-I) play a critical role in animal growth rates. We aimed to investigate the effect of GH and IGF-I genotypes on body weight (BW), dominance, and gene expression in slow-growing chickens at different ages. Methods: A total of 613 Korat chickens (KRs) were bred and divided into three groups by genotype - A1A1, A1A3, and A3A3 for GH and AA, AC, and CC for IGF-I. Chickens were weighed every two weeks, and liver and breast muscle tissues were collected at 10 weeks of age. Genetic parameters of KRs were estimated using ASReml software. The GH and IGF-I mRNA levels were measured by quantitative polymerase chain reaction. Significant differences between traits were analyzed using the generalized linear model. Results: A significant effect of GH genotypes on BW was found at most ages, and the A1A1 genotype had the highest value of BW. Compared with the A3A3 genotype, the A1A1 and A1A3 genotypes showed a higher dominance effect at 0 and 2 weeks, and genotype A1A1 had the highest value of dominance at 8 weeks of age. A difference in GH mRNA levels between genotypes was detected in breast muscle at 6 weeks and in the liver tissue at 2 weeks. In the case of IGF-I gene, the AA genotype had the highest BW at the beginning of life. Significant differences in BW dominance were found at 2 weeks. However, IGF-I mRNA levels were not different among genotypes in both breast muscles and liver tissues. Conclusion: Our results revealed that GH and IGF-I influence growth, but may not be involved in heterosis. GH can be used as a marker gene in selection programs for growth because the homozygous genotype (A1A1) had the highest BW at all ages. The IGF-I is not a useful marker gene for selection programs.

• Korean Journal of Ichthyology
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• v.26 no.3
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• pp.194-201
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• 2014

Age and growth of flathead grey mullet Mugil cephalus were estimated using samples collected by a two-side fyke net in the coastal water off Taean in 2008. Age was determined by examination of annuli in otoliths and total lengths at ages were back-calculated from otolth-body size relationship. Total length ranged from 239 to 605 mm and mainly between 400 and 550 mm. Observed ages ranged from 1 to 7 years old and mainly between 3 and 5 years old. Total length (L, mm) was linearly related to otolith radius (R, mm); L=15.3+87.9 R. Total lengths at the annulus formation in otolith were back-calculated by Frazer-Lee method. Estimated length at the age 1 was $316{\pm}40.6mm$ ($mean{\pm}SD$) showing a fast growth rate during the early growth stage. Total length at each age (t) showed a wide range indicating the big difference in growth rate among individuals. Growth in total length can be expressed by a Von Bertalanffy growth curve as $L_t=542[1-{\exp}\{-0.493 (t+0.769)\}]$.