• Korean Journal of Poultry Science
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• v.48 no.4
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• pp.177-184
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• 2021

Sex identification in day-old chicks is essential in the poultry industry. Currently, the feather-sexing using a sex-linked inheritance is a chick sexing method used extensively in the poultry industry. For chicks produced by feather-sexing, all females are early-feathering (EF) chicks and all males are late-feathering (LF) chicks. Therefore, investigating the effects of EF and LF phenotypes on production traits of chickens is critical. The purpose of this study was to analyze and compare the production performance between EF and LF chickens in Korean native commercial chickens. The results showed that the survival rate of the EF chickens was significantly higher than that of the LF chickens, from hatching to 12 weeks of age (P<0.05), with the highest difference observed in females. However, no significant difference was observed in body weight between the EF and LF chickens at almost all ages. In addition, no significant difference was observed between in feed utility, such as average daily feed intake and feed conversion ratio, between the EF and LF groups. In conclusion, although the survival rate of early-feathering chickens was superior to that of late-feathering chickens, no significant difference was observed in growth performance and feed utility among Korean native chickens. The results suggest that production capacity is not influenced by feathering type in the establishment of a breeder structure and production system for feather-sexing Korean native chickens, which is valuable for the practical application of feather-sexing in the poultry industry.

• Economic and Environmental Geology
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• v.19 no.spc
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• pp.175-191
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• 1986

The Geodo granodiorite intruded into the Joseon Supergroup is fine-grained at the marginal part, and medium-grained and more leucocratic at the central part. The Quartz monzonite porphyry intruded inte Precambrian granite and Geodo granodiorite has abundant plagioclase phenocryst. The Imog granite intruded into the Yulri Group and the Joseon Supergroup is mediumgrained biotite granite with partly pinkish feldspar phenocryst. The K/Ar ages obtained from the biotite of the Geodo granodiorite and Imog granite are Early ($111{\pm}1{\sim}107{\pm}1$ Ma) and Late ($93{\pm}1{\sim}92{\pm}1$ Ma) Cretaceous, respectively. The K/Ar sericite age of the quartz-sericite zone of the lower Jangsan quartzite occuring in the western area gave much younger age (about 170 Ma) than that of the Jangsan quartzite, that might be reset due to the regional metamorphism of the Daebo orogeny. The granitic rocks of the area are felsic to mafic, metaluminous to peraluminous, calc-alkalic (alkali-lime index${\fallingdotseq}$ 57) and I-type (magnetite-series) based on the chemical data_ And they appear to have been fractionated at the order of Geodo granodiorite, Quartz monzonite porphyry and Imog granite. In terms of mineralogy, geochemistry and K/Ar biotite age, a rock suite of monzodiorite, quartz monzodiorite and quartz monzonite-granodiorite in the Geodo stock was fractionally differentiated from a magmatic body from its margin to inward.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.73.1-73.1
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• 2015

Isolated galaxies in low-density regions are significant in the sense that they are least affected by the hierarchical pattern of galaxy growth and interactions with perturbers at least for the last few Gyr. To form a comprehensive picture of the star formation history of isolated galaxies, we construct a catalog of isolated galaxies and their comparison sample in relatively denser environments. The galaxies are drawn from SDSS DR7 in the redshift range of 0.025 < z < 0.044. We performed visual inspection and classified their morphology following the Hubble classification scheme. We have investigated the color-magnitude diagram and found elliptical and unbarred spiral galaxies in isolated systems are relatively fainter and bluer than those in denser regions. For the spectroscopic study, we make use of the OSSY catalog (Oh et al. 2011). Our analysis on the absorption-line properties based on the comparison with stellar population models suggests that isolated elliptical galaxies are likely to be younger and metal poorer, while isolated Sc-type galaxies seem to have older luminosity-weighted ages, than their high-density counterpart. In addition, according to the BPT diagnostics, early-type galaxies among isolated galaxies are rather evenly classified into star forming, composite, Seyfert and LINER, whereas their comparisons are mainly populated in the LINER region. On the other hand, late-type galaxies do not show any prominent difference. We discuss the evolutionary histories of isolated galaxies in the context of the standard ${\Lambda}CDM$ cosmology.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.46.1-46.1
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• 2015

M85 is a merger remnant galaxy in the Virgo Cluster, showing complex merging features. Globular clusters in M85 are a good tracer of its merging history. To investigate globular cluster system of M85, we obtain deep and wide field images of M85 in ugi filters covering one square degree using CFHT/MegaCam. We discover about 1,000 globular cluster candidates in these images. The color distribution of the globular cluster candidates within r < 5' from M85 does not show a clear bimodality and blue globular cluster candidates are more than red ones. These features are different from those in massive early-type galaxies. The spatial distribution of the globular cluster candidates is elongated along the faint stellar light of M85. We also investigate the spatial distribution of sub-populations of the globular cluster candidates with different color and brightness and estimate their ages based on their color. We discuss these results in relation with the formation history of M85.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.385-390
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• 2002

Autogenous shrinkage of concrete has been defined as decrease in volume due to hydration cement, not due to other causes such as evaporation, temperature change and external load and so on. For ordinary concretes, autogenous shrinkage is so little compared to the other deformations that it has been dignored. It has recently been proved, however, that autogenous shrinkage considerably increase with decrease in water to cement ratio. And it has been reported that cracking can be caused by autogenous shrinkage, when high- strength concretes were used. In this study, we propose an analytical system to represent autogenous shrinkage in cement paste in order to control crack due to autogenous shrinkage. The system is composed with the hydration model and pore structure model. Contrary to the usual assumption of uniform properties in the hydration progress, the hydration model to refine Tomosawa's represents the situation that inner and outer products are made in cement paste. The pore structure model is based upon the physical phenomenon of ion diffusion in cement paste and chemical phenomenon of hydration in cement particle. The proposed model can predict the pore volume ratio and the pore structure in cement paste under variable environmental conditions satisfactorily The autogenous shrinkage prdiction system with regard to pore structure development and hydration at early ages for different mix-proportions shows a reasonable agreement with the experimental data.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.5
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• pp.608-614
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• 2001

The effects of castration on growth and body composition of Javan rusa (Cervus timorensis russa) stags were examined at three slaughter ages in three experiments. Castration had no effects on growth rates, or liveweights at periodic weighings, at any stage in Experiments 1 and 2, when the stags were slaughtered at 19 and 13 months of age, respectively. In Experiment 3, monthly liveweights of castrated and entire stags were not significantly different until the stags were 21 months old. From this age, when they had recovered from their first rut season and were in their second spring/early summer, the entires grew more rapidly than the castrates. There were seasonal changes in growth in both treatments, indicating that pasture conditions influenced performance. Liveweights of entires and castrates were similar in stags slaughtered at 13 and 19 months, but castrates were smaller than entires at 25 months. Castration reduced the size of the head and skin, but there was little important effect of castration on body components at any slaughter age. Castration can be recommended as a management tool for rusa stags, especially if the animals are to be slaughtered before they exceed 19 months of age.

• Journal of Families and Better Life
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• v.33 no.6
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• pp.35-49
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• 2015

This study is to examine the relationships between experiences in the family of origin with fathers, parenting participation of fathers, and parenting stress of mothers. The subjects in this study consisted of 203 couples with children of ages 3, 4, and5 attending child care centers in the Gyeong-gi province. The results of this research are summarized as follows. First, experiences in the family of origin with fathers, have meaningful correlations with parenting participation of fathers and parenting stress of mothers. Also, parenting participation of fathers has meaningful correlations with parenting stress of mothers. Second, experiences in the family of origin with fathers have direct/indirect influence on parenting stress of mothers and parenting participation of fathers played a mediating role between the two variables. It is significant that these results give the basic research data for developing aparental education program that can lower parenting stress of mothers by parenting participation of fathers.

• Journal of The Korean Astronomical Society
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• v.32 no.2
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• pp.109-117
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• 1999

UBVI CCD photometry has been obtained for a region around the Wolf-Rayet star WR 12. We found two young stellar associations in the observed field: the nearer one comprises the field members of Vela OBI association at d = 1.8kpc, while the farther one is the young open cluster Bochum 7 (Bo 7) at d = 4.8kpc. The stars associated with Bo 7 showed no central concentration which suggests that Bo 7 is not a young open cluster but simply a local concentration in the density of young stars belonging to the OB association (Vel OB3). These two associations have similar ages but remarkably different mass function slopes ($\Gamma$ = -2.1 $\pm$ 0.3 for Vel OBI and -1.0 $\pm$ 0.3 for Bo 7). The stars in Vel OBI shows an evident age spread (${\Delta}T\~ 9Myr$). We also found two strong H$\alpha$ emission stars - WR 12 and $\sharp$1066 - from narrow band H$\alpha$ photometry.

• Korean Journal of Child Studies
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• v.36 no.3
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• pp.1-18
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• 2015

This study tested the relationship between mothers' beliefs about their children's emotions and the children's emotional regulation, using the mothers' positive and negative emotional expressiveness as mediators. The participants comprised 511 mothers with children whose ages ranged from 3 to 5 years, from 11 early childhood educational institutions located in Seoul and Gyeonggi Province. The survey data were analyzed using the SPSS 21.0, AMOS 21.0 and Mplus 6.12 programs. The main results were as follows. First, there were significant correlations among the three variables (i.e., mothers' beliefs about their children's emotions, the children's emotional regulation, and the mothers' emotional expressiveness). Second, both the mothers' beliefs about their children's emotions and the mothers' emotional expressiveness predicted in a significant manner the children's degree of emotional regulation. Third, the mediating effects of the mothers' emotional expressiveness were found to be significant. This indicated that the mothers' emotional expressiveness can be one means by which their children's emotional regulation can be increased, and this needs to be taken into account when designing educational and counseling programs.

• Journal of Korean Public Health Nursing
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• v.15 no.1
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• pp.1-12
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• 2001

This study. aimed to categorize attitude of smoking behaviors among female student smokers and to provide useful data for development of anti-smoking programs was conducted from Aug. 22 to Nov. 1. using the Q-method. After reviewing the literature the researcher proceeded to interview 10 female students, then developed a statement form consisting of 40 items, and then 30 female student smokers were sampled. The collected data were coded after having been scaled from 1 to 9 points, and analyzed using the PC QUANL program. Three types were identified; The first type focused on the right of the individual to smoke. the second type of students used smoking as a way to relieve their stress, and the third type of students wanted to use smoking as a tool to relate with their peer group. They smoked in closed areas, i.e. rest rooms. coffee shops - places that are not well ventilated and deep inhalation occurs. most subjects of the study started smocking at early ages(the average age was 17). Smoking at this age is especially harmful. It is suggested that the results of the study may be useful for designing anti-smoking health programs including health promotion.