• 한국동물학회지
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• 제3권2호
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• pp.13-18
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• 1960

For the study on the sex ratio in natural populations of the different localities, the amphibian species were collected as the materials at the seven localities in Korea, and were obtained the following results. The sex ratios of each amphibian species suggest that each has it's own specific sex rations the following list. Rana nigromaculata H. : 109-39, Rana rugosa SCH. : 67.44, Rana temporaria coreana O. : 158.45, Hyla arborea japonica G. : 137.70. In Rana nigromaculata H. the average sex ratio was 109.39 as the above list, and its was reached statistically significant level according to the different localiies. The sex ratio was generally higher in the eastern area than that in the western area in this country. The sex ratio of the adult frogs of Rana nigromaculata H. was 135.18 , and it has a statistically significant level by each locality but the sex ratio of the younger frogs of the same species was 100.97 which was a little lower than that in the adult, and it was not laid at a significant level according to the localities. There is no doubt that the difference of sex ratios according to the localities was mainly due to the different ratios of the adult frogs which were effected on the constitution of sex by environmental factors in each locality.

• 한국수학사학회지
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• 제21권4호
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• pp.79-86
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• 2008

우리나라의 출생 성비는 자연 상태에서의 출생 성비(natural sex ratio at birth)로 추정되는 105를 초과하고 있는데, 그 원인 중 하나로 남아선호사상으로 인한 인위적인 출산이 있다(e.g. 임신중절 등). 본 연구에서는 임신 중절 없이 남아를 낳을 때까지만 출산을 하려는 가정(family)들의 존재가 출생 성비를 높이는 데에 기여하는지를 알아보기 위하여, 이러한 가정들과 출생 성비(sex ratio at birth)의 관계를 분석하였다. 그 결과, 남아 한 명을 낳을 때까지만 출산을 하려는 가정의 수가 무한으로 발산할수록 출생 성비는 자연 상태에서의 출생 성비에 확률적으로 수렴하는 것을 알 수 있었다. 즉, 남아를 낳을 때까지만 출산을 하려는 가정들의 존재는 출생 성비에 영향을 미치지 않음을 확인하였다.

• 한국발생생물학회지:발생과생식
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• 제16권3호
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• pp.177-183
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• 2012

This study attempts to propose the possibility of the sex reversal in Tegillarca granosa and Ruditapes philippinarum by confirming the changes in the sex ratio with the shell length (SL) in the same population level. For analysis of sex ratio with SL, 1500 individuals of T. granosa (SL 10.1-45.0 mm) and 712 individuals of R. philippinarum (SL 15.1-70.0 mm) were used. Sex was analyzed histologically. The average sex ratios (F:M) of T. granosa and R. philippinarum were 1:1.22 and 1:0.96, respectively. However, sex ratio was found to differ when the clams were divided into groups according to SL in 5.0 mm intervals. Both species displayed the tendency of increase in the proportion of female with increase in SL. In this study, changes in the sex ratio in accordance with the growth of T. granosa and R. philippinarum are determined to be indirect evidence that signifies their sex reversal.

• 한국인구학
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• 제17권2호
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• pp.98-115
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• 1994

This study is attempting to examine the possible determinants of the rise of the sex ratio at birth from 106 to 110 in past decade in Taiwan. The basic hypothesis for the sudden rise of the sex ratio at birth is due to a combination of prenatal sex determination and abortion. The reasoning for this hypothesis involves three types of considerations - motivation, norm, and access. The theory is evaluated by analyzing data from birth registration and a large and representative sampie of Taiwanese wives of childbearing age. The empirical data seem to support the theoretical preposition and the basic hypothesis that the rise of the sex ratio at birth in Taiwan is due to a combination of prenatal sex determination and abortion. There is striking evidence of son-preference in the rise of the sex ratio at birth in higher birth order. In 1990 the sex ratio was 119 for third births and 128 for fourth and fifth births compared to the expected 106. Also, the 1991 KAP data indicated that women who have only daughters but no any son are more likely to make prenatal sex screening and terminate their pregnancies in male live births at higher birth order. Obviously, genetic diagnosis through chorionic villus sampling which was available in recent years was misused for prenatal sex determination and sex selective abortion.

• 한국인구학
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• 제11권2호
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• pp.67-76
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• 1988

The purpose of this study was to find out the factors affecting birth sex ratio which had revealed alarmingly higher in recent years. This study was conducted to get hold of the basic data such as the sex ratio of live births which had been delivered at 5 general hospitals in Taegu from 1982 to 1986. And author chose Dongsan Medical Center from those 5 hospitals for further detailed study, and reviewed 1,286 medical records of mothers who had birth in each February and March from 1984 to 1987. Of these 1,286 deliveries, 30 cases were twin deliveries, which added the total children numbers to 1,316. The findings of this study were as follows: The average of birth sex ratio( 114.5) for 5 years at five general hospitals in Taegu was slightly higher than the traditional birth sex ratio( 102-107) and the highest was 123.4 in 1985. There was no significant difference in birth sex ratio by mother's educational level, her religion nor father's occupation. The birth sex ratio of the cases whose mother was above 35 years old was significantly high(400.0), that of the cases who were born to the mothers who had more than 3rd parity was significantly high(309.5), and that of the cases whose mother had more than two daughters and no son was also significantly high (330.7). The birth sex ratio of the cases who did not have ultrasonogram on their prenatal visits was 87.8. In contrast to this, that of the cases who had ultrasonogram was significantly higher( 135.5). Of the mothers who have more than two daughters and no son' 80.4% (45 cases) had ultrasonogram and their newborn's birth sex ratio was significantly high(542.9). Of the cases who were born to more than 3rd parity mothers, 75.6%(65 cases) of their mothers had ultrasonogram and their sex ratio was significantly high(441.6). It was revealed by this study that the birth sex ratio is changed to significantly high due to sex confirmation of the fetus by ultrasonogram. Thus it is recommended that the value related to having equality of sexes must be ingrained by changing the various social systems and value systems which is now aggrevating the son preference and should provide controlling system which can prohibit the ultrasonogram for sex confirmation only.

• Animal cells and systems
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• 제4권2호
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• pp.131-140
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• 2000

The pattern of variations in cone sex ratio and pollen traits such as pollen number and size was examined for two years in populations of red pines In Korea. We evaluated; (1) the relationship between tree size and cone sex ratio, (2) the relationship between year and cone sex ratio, and (3) the relationship between cone sex ratio and pollen traits. Larger trees in height and circumference at breast height produced more male as well as female cones. However, cone sex ratio was independent of these plant sizes. Across the two populations, both female cone numbers per tree and male cone numbers per new shoot increased 2.2 and 1.2 times, respectively, in 1999 compared to 1998, while the yearly pattern of male cone-bearing shoots per tree differed significantly between populations. Thus, cone sex ratio varied significantly between years in one of the two populations. Pollen traits such as the number of pollen grains and diameter did not vary significantly among populations. Pollen diameter and grain numbers per male cone were significantly negatively correlated with the cone sex ratio in two populations and one population, respectively. Trees which stopped female cone production in the first year and those which produced female cones in both years differed in the cone sex ratio and pollen size in the second year. The long duration of one reproductive episode and the potential of masting in red pines emphasize the need to conduct long-term studies on the dynamics of cone production, cone sex ratio, and simultaneous changes in pollen traits in red pines.

• 한국발생생물학회지:발생과생식
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• 제18권2호
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• pp.73-78
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• 2014

This study attempts to propose the possibility of the sex reversal in Sinonovacula constricta and Gomphina veneriformis by confirming the changes in the sex ratio with the shell length in the same population level. For analysis of sex ratio, 100 individuals of S. constricta (SL 26.5-95.0 mm) and 2385 individuals of G. veneriformis (SL 15.1-60.1 mm) were used. Sex was analyzed histologically. Both species displayed the tendency of increase in the female proportion with increase in shell length. In this study, changes in the sex ratio in accordance with the growth of S. constricta and G. veneriformis are determined to be indirect evidence that signifies their sex reversal.

• 한국인구학
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• 제7권1호
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• pp.78-123
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• 1984

This study is attempting to examine the possible determinants of the rise of the sex ratio at birth from 106 to 110 in past decade in Taiwan. The basic hypothesis for the sudden rise of the sex ratio at birth is due to a combination of prenatal sex determination and abortion. The reasoning for this hypothesis involves three types of considerations - motivation, norm, and access. The theory is evaluated by analyzing data from birth registration and a large and representative sampie of Taiwanese wives of childbearing age. The empirical data seem to support the theoretical preposition and the basic hypothesis that the rise of the sex ratio at birth in Taiwan is due to a combination of prenatal sex determination and abortion. There is striking evidence of son-preference in the rise of the sex ratio at birth in higher birth order. In 1990 the sex ratio was 119 for third births and 128 for fourth and fifth births compared to the expected 106. Also, the 1991 KAP data indicated that women who have only daughters but no any son are more likely to make prenatal sex screening and terminate their pregnancies in male live births at higher birth order. Obviously, genetic diagnosis through chorionic villus sampling which was available in recent years was misused for prenatal sex determination and sex selective abortion.

• 한국가축번식학회지
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• 제8권2호
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• pp.92-96
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• 1984

This study was carried out ot examine the sex ratios of offspring in swine. The sex ratios were obtained on the basis of the data from 15,892 pigs produced by 1,728 litters of Landrace, Large Yorkshire, Hampshire and Duroc breeds at National Animal Breeding Institute from 1975 to 1980. The results obtained are summarized as follows: 1. The sex ratio of total offspring was 51.47% for male and significant at 5% level, and Landrace and Duroc breeds were 51.46% and 52.27% for male and significant at 5% level, respectively, but no significant difference between the breeds. 2. The sex ratio of offspring by years was 52.74% for male and significant at 5% level in 1979, but no significant difference for other years and between years. 3. The sex ratio of offspring by seasons were a little highly 51.65% and 51.25%, for male in spring and autumn, but no significant difference, respectively. 4. The sex ratio of offspring by parities were 52.65% and 55.81% for male in groups of the 3rd to 4th and the 5th to 6th parity, and significant difference at 5% and 1% level, respectively. 5. The sex ratio of offspring by groups of litter size was 52.65% for male in 1 to 6 heads group, and significant difference at 5% level, but no significant difference between groups of litter size.

• 현장농수산연구지
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• 제16권1호
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• pp.135-141
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• 2014

양식산 넙치의 인위적인 선별에 따른 암수 성비를 자연산 넙치의 성비와 비교하기 위하여 양식산과 자연산 각각 3개 지역에서 시료를 채집하여 총 841마리를 분석 하였다. 조사된 자연산 넙치의 성비는 암컷과 수컷의 비율이 각각 1.10~1.93, 0.52~0.91으로 암컷의 비율이 높게 나타났다. 양식산 넙치에서는 암컷의 비율이 0.20~2.15였으며, 수컷의 비율은 0.46~4.88이었다. 양식산 넙치의 경우 울진과 완도집단의 암컷 비율이 각각 2.03, 2.15로 높게 나타났으며, 진도집단은 반대로 수컷의 비율이 4.88로 아주 높게 나타났다. 이렇게 암수의 성비가 높게 나타난 것은 선별에 의한 결과라고 추정된다. 또한 각 집단별 체장조성에 따른 암컷의 비율은 체장이 클수록 암컷의 비율이 높게 나타났다. 따라서 넙치양식에서 성장이 빠른 암컷을 사육하는 것이 경제적이지만 인위적인 종묘생산에서 크기 선별로 작은 개체들이 자연생태계에 방류된다면 자연집단의 성비 불균형에 영향이 있으므로 자원조성을 위한 종묘방류는 균형 있는 성비도 고려하여야 할 것으로 생각된다.