• Pediatric Infection and Vaccine
• /
• v.4 no.2
• /
• pp.240-256
• /
• 1997

Purpose: To evaluate the hepatitis B vaccination program which has been conducted since 1980, Korea. Methods: This study was carry out self reported questionnaire and serologic test covering 2,072 elementary school students who were born between 1980 and 1987, selected by cluster sampling. The HBV serologic markers (HBsAg, Anti-HBs and Anti-HBc) were tested by radioimmunoassay (RIA). The contents of questionnaire include demographic data of students and parents, vaccination status, vaccination frequency, vaccination age, past history of mother's HBV test. Results: 1) The HBsAg positive rates by sex showed 3.7% for male and 2.7% for female, representing an average rate of 3.4%. The HBsAg positive rates by age group showed 5.6% for 13 years and l.5% for 6 years, representing a tendency of lowering rate as ages being younger. 2) The pre-natal HBV test rate was 10.2%, while post-natal HBV test rate was 42.5%. The test showed that the parents' educational level being higher than others, the pre- and post-natal HBV test showed higher rates. In case the fathers occupation being office worker, the post-natal HBV test showed a higher rate compared with other occupation. 3) Overall vaccination rate was 82.6%, complete vaccination rate 69.8%, booster injection rate 42.8%. The vaccination rate, complete vaccination rate and booster injection rate increased as the age being younger. If the educational level of parents were higher, the vaccination rate, complete vaccination rate and booster injection rate showed higher rates. Younger students showed younger vaccination age, and higher educational background of family showed younger vaccination ages. 4. With regard to positive rate of HBV markers by vaccination age, HBsAg and Anti-HBc positive rate showed higher degrees in the following order; preschool age (1-6 years), school age (6-13 years) and infancy (0-1 year). Anti-HBs positive rate was increased as the frequency of vaccination increased. Five years after initial complete vaccination, minimum protective rate was lowest, 69.6%.

• Development and Reproduction
• /
• v.11 no.3
• /
• pp.195-203
• /
• 2007

Sex determination and sex differentiation are influenced by genotype in many gonochoristic fish. Cytochrome P450 aromatase (CYP19) is the terminal enzyme in steridogenic pathway that converts androgens into estrogens. In this study, partial fragments of aromatase genes (ovarian aromatase, P450aromA and brain aromatase, P450aromB) were cloned and sequenced in Korean rockfish (Sebastes schlegeli), and gene specific primers were designed based on their sequences. Using these primers, aromatase gene expression during sex differentiation was investigated by RT-PCR. Expression of these aromatase genes were detected both in the head and body parts at 35 dab (days after birth). The number of fish that expressed the aromatase genes decreased at 52 dab, implying down-regulation of these genes. However, these genes were expressed at 59 dab in almost all fish studied here. The expression patterns of both genes are similar throughout the investigated period except for 45 dab where the expression of P450aromB was detected in more fish than that of P450aromA both in the head and body parts. Timing of sex differentiation in this species has been shown to be at around $50{\sim}65$ dab by histological analysis. However, the results from this study suggest that sex differentiation of rockfish may take place $1{\sim}2$ weeks earlier than the period proposed previously. The results also suggest that the mechanism of sex differentiation in viviparous fish may be similar to that in oviparous fish in terms of the importance of aromatase action during the critical period.

• Journal of Aquaculture
• /
• v.20 no.1
• /
• pp.47-50
• /
• 2007

The primordial germ cells of the oblong rockfish, Sebastes oblongus were buried under fibrous mesenchymal tissues between gut and mesonephric duct of pre-larva with 4.0 mm total length (TL) at 1 day after the parturition. In the juvenile of 22.0 mm TL at 71 days after the parturition, the gonad composed of a large number of gonial cell and formed of cavity along the lateral side of the gonad, differentiated to the ovary. At this time, the gonad formed seminiferous tubules by somatic cells, was differentiated to the testis. The smallest oblong rockfish that possessed primary oocytes was about 42.1 mm TL at 141 days. Spermatogonia remained quiescent until most fish were over 42.1 mm TL at 141 days. The oblong rockfish the differentiated directly into male or female without an intermediate female phase at the early indifferentiated stage. Therefore, the oblong rockfish belongs to the differentiated type of gonochoristic teleosts.

• Korea journal of population studies
• /
• v.10 no.2
• /
• pp.17-45
• /
• 1987

This study contributes to understanding women's labor market behavior by focusing on a particular set of labor force transitions - labor force withdrawal and entry during the period surrounding the first birth of a child. In particular, this study provides a dynamic analyses, using longitudinal data and event history analysis, to conceptualize labor force behaviors in a straightforward way. The main research question addresses which factors increase or decrease the hazard rates of leaving and entering the labor market. This study used piecewise Gompertz model, following the guide of the non-parametric analysis on the hazard rates, which allowed relatively detailed description on the distribution of timing of leave and entry to the labor market as parameters of interest. The results show that preferences and structural variables, as well as economic considerations, are very important factors to explain the labor market behavior of women in the period surrounding childbirth.

• Korean Journal of Environment and Ecology
• /
• v.33 no.5
• /
• pp.497-505
• /
• 2019

Winter hibernation in wildlife is a unique physiological mechanism for survival. For Asiatic black bears (ABBs, Ursus thibetanus ussuricus), hibernation is a very important but dangerous time for the cubs to be born. This study surveyed ABBs living in Mt. Jiri To examine the relationship between the temperature during hibernation and the hibernation days. The survey found that the average start and end dates of hibernation was December 7 and April 20, respectively. The average day of hibernation for females who gave birth was $167.8{\pm}22.6$ days. The average temperature of 5 days before hibernation was $0.6{\pm}4.1^{\circ}C$, the average temperature during hibernation was $1.3{\pm}2.43^{\circ}C$, and the average temperature of five days before the end of hibernation was $12.6{\pm}3.1^{\circ}C$. The hibernation days of the females that did not give birth to cubs and the males were $120.4{\pm}25.7$ days and $113.6{\pm}25.8$ days, respectively. The average temperatures of 5 days before hibernation was $2.1{\pm}4.2^{\circ}C$ and $-1.8{\pm}3.9^{\circ}C$, respectively. The average temperature during hibernation was $-0.2{\pm}1.6^{\circ}C$ and $-0.4{\pm}2.4^{\circ}C$. The average temperatures of five days before the end of hibernation were $7.8{\pm}3.6^{\circ}C$ and $7.8{\pm}4.4^{\circ}C$. These results indicate that females giving birth to cubs have higher hibernation days and average temperatures than the females that do not give birth and the males, which is due to the process of raising cubs during hibernation. The hibernating days and mean temperature for the groups in each lifecycle did not show any difference between the groups. This study is meaningful in that it disclosed the characteristics of hibernating intrinsic behaviors of ABBs. It observed the specific hibernation period and temperature of ABBs bears inhabiting in Mt. Jiri and examined the difference by sex, female(giving birth) and life cycle group according to temperature. The results of this study can be used to prevent the conflict between ABBs and humans in winter and spring and establish the preservation management plan.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.29 no.1
• /
• pp.44-50
• /
• 1996

Sex differentiation in the rockfish, Sebastes schlegeli, was studied by using a histological method for the appearance of primordial germ cell, formation of primitive gonad and differentiation of female and male. The primordial germ cells were buried under fibrous mesenchymal tissue between gut and mesonephric duct of pre-larva with a total length (TL) of 6.3 mm at 2 days after parturition. In juvenile of TL $5.2\~5.9cm$ at 65 days after parturition, the gonad composed of a large number of genial cell and formed of cavity along the lateral side of the gonad, differentiated to the ovary. At this time, the gonad formed seminiferous tubules by somatic cells, differentiated to the testis. In juvenile of TL $7.0\~7.2cm$ cm at 115 days after parturition, gonads divided into testis contained pigment cell and ovary absent pigment cell. S. schlegeli differentiated directly into male or female without an intermediate female phase at early indifferentiated stage. Therefore, S. schlegeli belongs to the differentiated type of gonochoristic teleosts. At 350 days after parturition, sex ratio was approximately 1 : 1(p>0.05).

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.31 no.5
• /
• pp.713-720
• /
• 1998

Experiments on the control of rockfish, Sebastes inermis reproduction were performed by artificially changed water temperature (WT) and photoperiod (PP). The experiments were divided into three conditions; artificial changes of both WT and PP delayed two months against their natural variations (Exp.I), natural WT and PP replaced with artificial light (Exp.II) and natural WT and PP (Exp.III) from September to April (220 days). Initial gonadosomatic index (GSI) in female groups of experiments was 0.2. Female GSI of responded group in Exp.I began to increase from December and reached the highest value in February with 15.0, while the un-responded group kept the lower value during the experimental period. Female GSI of Exp.II and Exp.III reached the highest values in January with 13.0 and 14.7, respectively. Male GSI of Exp,I reached the maximum in October, and that of Exp.II and III reached the maximum in November and then rapidly decreased. Among the experimental groups, male GSI did not show the different tendency. Monthly changes of hepatosomatic index in both sexes showed the reciprocal tendency with those of GSI. The control of WT and PP did not affect on the changes of HSI and condition factor of rockfish. From the histological observations, maturation of ovary was delayed by the changes of WT and PP, but that of testis was not influenced. Judging from the above results, the maturation and parturition of female rockfish could be delayed one or two months by artificial changes of WT and PP.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.16 no.2
• /
• pp.65-74
• /
• 2013

A research program for the roe deer (Capreolus pygargus) has been set up at the Jeju Experimental Forest of Warm-temperate and Subtropical Forest Research Center in Jeju Island. To explore the home range size and habitat environment, 3 males and 3 females have been captured and released with GPS-CDMA based telemetry since 24th April 2012. Among them 2 females were captured at Hannam Forest of Seoguipo, were pregnant and monitored by the tracking system. There are significantly different patterns in behavior around the parturition. After parturition they show recurrence behavior toward one point in the forest, while they have irregular patterns in moving before. To calculate the home range size, the MCP (minimum convex polygon) and Kernel Method are applied through the extension of ESRI ArcView GIS 3.2a. The pregnant female captured 9th May 2012 has the size of MCP=67ha and Kernel 95%=0.5ha and the pregnant female captured 12th July 2012 has the size of MCP=82ha and Kernel 95%=0.9ha. Although a fawn could move immediately just after the birth likely others to avoid any risks, they stay at very narrow space significantly, and the size become wider when more time goes by. Furthermore, they mainly have a home range away from human activity area such as forest tracking roads. The habitat environment for the parturition is summarized as 40years old cryptomeria forests with new sprouting shrubs for foods, which are the controlled forest through the thinning and removing shrubs 2 years ago. This means that forest works could cause positive results for the parturition and survival of young. The period of parturition is earlier than highland in Jeju Island, the size of home range is narrower than other countries, and the habitat environment of the shelter for a fawn is similar to previous research in other countries.

• Korea journal of population studies
• /
• v.14 no.2
• /
• pp.78-87
• /
• 1991

본 연구는 대도시의 인구이동률의 장기적 추세를 분석하기 위하여 시도되었다. 본 연구에서는 멕시코의 중소도시인 오하카(Oaxaca)에서 구역별로 추출된 633가구를 대상으로, 그들의 거주지 이동상황 및 이에 영향을 미치는 인구.사회학적 요인에 관한 설문을 실시하였다. 연구결과, 가족의 거주지 이동률은 결혼후 5년 이내가 년간 23.23 퍼센트로서 가장 높았는데, 이것은 결혼초기에 출산과 관련한 주거공간 요구의 급격한 증가가 주된 원인인 것으로 해석되었다. 또한 연대별로는 1960년대에 특히 많은 주거지 이동이 있었는데, 이는 이 시기의 범 세계적인 아기풍년(Baby Boom)에 따른 급격한 자녀수의 증가와 관련된 거주공간의 수요확대로 인한 현상으로 해석되었다.

• 한국벤처창업학회:학술대회논문집
• /
• 2019.04a
• /
• pp.75-78
• /
• 2019

통계청의 '2018년 경력단절여성 현황'을 보면, 지난해 4월 기준으로 15~54세 기혼여성 가운데 경력단절여성은 184만7000명으로 전년 대비 1만5000명(0.8％) 늘었다. 경력단절여성의 비중도 20.5％로 1년 전보다 0.5％포인트 상승했다. 2015년 21.7％, 2016년 20.5％, 2017년 20.0％로 점차 떨어지다가 다시 반등세로 돌아섰다. 경력단절여성의 경우 재취업 성공도 힘들었다. 지난해 경력단절 후 다시 취업한 기혼여성은 1년 전보다 50만7000명(19.6％) 줄어든 208만3000명으로 2014년 통계작성 이후 가장 적었다. 경력단절 후 다시 취업한 이들의 비중도 지난해 23.1％로 최저였다. 경제활동을 시작하는 20대부터 경력을 쌓아가는 30대, 40대는 노동자의 생산성이 증폭되는 시기인데, 정작 여성은 이 연령대에 결혼 임신 출산 육아로 인해 경력이 단절되는 현실이다. 본 연구는 우리나라 경력단절여성의 자기지각, 사회적지지 및 대처행동이 취창업의지와 삶의 질에 미치는 영향에 대한 연구로 최근의 정부정책에 있어서 이슈가 되고 있는 사항들을 연구할 예정이다.