Estimation of the Stillbirth Rate in Twin Pairs According to Zygosity

2007 ◽  
Vol 10 (3) ◽  
pp. 508-513 ◽  
Author(s):  
Johan Fellman ◽  
Aldur W. Eriksson
Keyword(s):  
Sex Ratio ◽  
Young Mothers ◽  
Stillbirth Rate ◽  
Male And Female ◽  
England And Wales ◽  
Common Opinion ◽  
Secondary Sex Ratio ◽  
The Difference ◽  
Mz Twins

AbstractIt is common opinion that the stillbirth rate is higher among monozygotic (MZ) than among dizygotic (DZ) twins. This is supported by the fact that stillbirth rates are higher among same-sexed than among opposite-sexed twins, and the relatively high stillbirth rates among twins of young mothers. In this study we present a method to estimate the stillbirth rates for MZ and DZ twins and identify the difference. We performed analyses based on the assumptions of (a) Weinberg's differential rule, including the assumption that the secondary sex ratio is 100, (b) the stillbirth rates among opposite-sexed twins hold for all DZ twins, and (c) the stillbirth rates estimated for MZ and DZ male and female twins yield for both sexes the observed total number of stillborn twins. Our methods are applied to data from Sweden, 1869–1967, the Åland Islands, 1750–1949, Saxony, 1881–1900, and England and Wales, 1996–2003. We observed that the ratio between the estimated stillbirth rates among MZ and DZ twins were on average 1.75, and the ratio among same-sexed and DZ (opposite-sexed) twins were on average 1.31. For Sweden and Saxony similar values were obtained, but for England and Wales the values were higher and for Åland lower. With exception of Åland, the estimated stillbirth rates were in all populations the lowest for DZ, medium for same-sexed and highest for MZ twins.

II.—Prenatal Death in the Pig and its Effect upon the Sex-Ratio

1927 ◽  
Vol 46 ◽  
pp. 9-14 ◽  
Author(s):  
F. A. E. Crew
Keyword(s):  
Sex Ratio ◽  
Sex Chromosome ◽  
Selective Mortality ◽  
Cytological Evidence ◽  
Male And Female ◽  
Primary Sex Ratio ◽  
The Future ◽  
Secondary Sex Ratio

The cytological evidence concerning the pig is that the sex of the future individual is determined at the time of fertilisation, and that in respect of the elements of the sex-chromosome sex-determining mechanism the male is digametic. If this is so, if the two sorts of sperm are produced in equal numbers, if each kind is equally viable and functional, and if fertilisation is at random, then a primary sex-ratio (that which obtains at the time of conception) of equality must follow. If male and female zygotes are equally viable, then the secondary sex-ratio (that which obtains at the time of gestation) will also be equality. A secondary sex-ratio other than equality must be the reflection of an unequal primary sex-ratio, the result of a differential production of the two sorts of gametes elaborated by the digametic sex, of a selective fertilisation by these, or of a sexually selective mortality among the embryos or/and fœtuses. A secondary sex-ratio of equality can follow a pronounced inequality in the primary sex-ratio if a sexually selective mortality operates prenatally.

EARLY DIFFERENTIAL MORTALITY IN NEODIPRION SERTIFER (HYMENOPTERA: DIPRIONIDAE)

1974 ◽  
Vol 106 (1) ◽  
pp. 1-10 ◽  
Author(s):  
L. A. Lyons ◽  
C. R. Sullivan
Keyword(s):  
Sex Ratio ◽  
Larval Period ◽  
Differential Mortality ◽  
Neodiprion Sertifer ◽  
Primary Sex Ratio ◽  
Secondary Sex Ratio ◽  
The Difference ◽  
Relationship Of ◽  
The Relationship ◽  
Early Larvae

AbstractIn Neodiprion sertifer (Geoff.), mortality is greater in males than in females in the egg stage and probably also among early larvae, but in the late larval period females are more susceptible. The evidence consists of the difference in mortality between all-male and mixed (male + female) colonies, as well as the relationship of secondary sex ratio to preceding mortality and the number of survivors per colony. The effect of differential mortality on estimation of the primary sex ratio is discussed.

scholarly journals Optimization of reproduction of ricefish endemic to Southeast Sulawesi Oryzias woworae Parenti & Hadiaty, 2010 through different sex ratios in spawning

2021 ◽  
Vol 21 (3) ◽  
pp. 235-251
Author(s):  
Mohamad Ayip Firmansyah ◽  
Mustahal Mustahal ◽  
Mas Bayu Syamsunarno ◽  
Muh Herjayanto
Keyword(s):  
Water Quality ◽  
Sex Ratio ◽  
Ornamental Fish ◽  
Egg Hatching ◽  
Female Ratio ◽  
Male And Female ◽  
Status Information ◽  
The Difference ◽  
Endangered Status ◽  
Male To Female

Oryzias woworae has a beautiful color and has been traded as ornamental fish. This species is an endemic ricefish from Muna Island, Southeast Sulawesi, and is threatened with endangered status. Information on the optimal spawning sex ratio in O. woworae is unknown. This study aimed was to examine the optimization of reproduction based on the sex ratio of male: female broodstock O. woworae involved in spawning. The sex ratio of male: female spawning broodstock used were 1:1, 1:2, 1:3, and 1:4. The male and female brooders used had a total length of 3,1 ± 0,5 cm and 2,5 ± 0,5 cm. After adaptation, the broodstock of O. woworae was put into aquariums according to the treatment, and each container contained three spawning substrates. The harvesting of eggs on the substrate is carried out two times a day. The results showed that spawning O. woworae with a ratio of 1♂: 4♀ produced the lowest number of eggs and was significantly different with ratios of 1♂: 1♀ and 1♂: 2♀ (P<0,05). The ratio of 1♂ : 3♀ gave the highest egg hatching of 55% but was not significantly different from other treatments (P>0,05). The difference in male and female ratios did not affect the survival rate of O. woworae larvae (P>0,05), with values from 91,9-100%. The highest larvae produced was found in the spawning ratio of 1♂ : 3♀ with 37 larvae but not significantly different from other treatments (P>0,05). The water quality values during the study were temperature 26,5-310C, pH 5,5-8,8, and dissolved oxygen 5,3-6,0 mg L-1. O. woworae broodstock spawning can be optimized with a male to female ratio of 1:3.

Altering systemic acid - base balance through nutrition failed to change secondary sex ratio

2007 ◽  
Vol 19 (8) ◽  
pp. 887 ◽  
Author(s):  
John R. Roche ◽  
Julia M. Lee
Keyword(s):  
Sex Ratio ◽  
Maternal Blood ◽  
Pregnant Mouse ◽  
Breeding Period ◽  
Acid Base Balance ◽  
Urine Ph ◽  
Blood Ph ◽  
Secondary Sex Ratio ◽  
Base Balance ◽  
The Difference

There is evidence that differences in either maternal blood pH or dietary mineral content can result in alterations in secondary sex ratio in mammals. Altering the proportions of certain dietary minerals is known to influence blood pH, offering a possible explanation for this effect of diet on secondary sex ratio. The present study was performed to investigate whether altering blood pH by manipulating the dietary cation–anion difference (DCAD) would alter secondary sex ratio. The DCAD is calculated (in mEq per 100 g dry matter) as the difference between metabolically strong cations (Na + K) and metabolically strong anions (Cl + S) in the diet. Three hundred female mice were randomly allocated to either a low or high DCAD ration for 3 weeks before coitus. Urine pH was monitored before beginning the experiment, as well as before and after the breeding period, as a proxy for blood pH. Mice on the low DCAD diet had a lower urine pH (mean (± s.d.) 6.0 ± 0.1) than mice on the high DCAD diet (8.2 ± 0.6), but DCAD did not affect the percentage of mice that became pregnant, the number of offspring per pregnant mouse or the sex ratio of the neonate group. These results suggest that blood pH alone does not alter sex ratio and that an altered systemic pH is not the reason for reported mineral-related variations in sex ratio.

Perceived social support and burden of care of male and female caregivers of patient with schizophrenia

2017 ◽  
Vol 8 (1) ◽  
pp. 10
Author(s):  
Narendra Kumar Singh ◽  
Nishant Goyal
Keyword(s):  
Social Support ◽  
Perceived Social Support ◽  
Family Members ◽  
Well Being ◽  
Cross Sectional Study ◽  
Burden Of Care ◽  
Cross Sectional ◽  
Male And Female ◽  
The Social ◽  
The Difference

Background: Schizophrenia is associated with a high familial, social and economic burden. Schizophrenia is also associated with a high level of disability which may create impediments on the social and economic areas of the patients as well as on their respective family networks. Families with schizophrenia may encounter problems such as impairment of health and well being of other family members, restriction of social activities of the family members and shrinking of support from the social network. Aims: The present study examined the difference in perceived social support and burden of care between the male and female caregivers of patients with schizophrenia. Methods: This was a cross-sectional study examining the difference in perceived social support and burden of care between the male and female caregivers of patients with schizophrenia. The sample consisted of 60 (30 male and 30 female) caregivers of the patients with the diagnosis of schizophrenia as per ICD-10-DCR. Results and Conclusion: This study revealed that male caregivers perceived more social support and less burden of care as compared to female caregivers. Key words: Gender, social support, burden

The DEVELOPMENT OF Elaeidobius kamerunicus FAUST POPULATION AFTER INTRODUCTION AND THE IMPROVEMENT OF OIL PALM FRUIT SET IN SERAM ISLAND, MOLLUCAS, INDONESIA

2016 ◽  
Vol 24 (1) ◽  
pp. 47-55
Author(s):  
Agus Eko Prasetyo ◽  
Agus Susanto
Keyword(s):  
Sex Ratio ◽  
Oil Palm ◽  
Fruit Set ◽  
Average Risk ◽  
Palm Fruit ◽  
Male And Female ◽  
Risk Of Death ◽  
North Sumatra ◽  
Female Flowers ◽  
Elaeidobius Kamerunicus

Elaeidobius kamerunicus is the main pollinating agent in oil palm plantations in Indonesia today. The development of oil palm plantations in new areas requires introduction of these insects, moreover the new areas are located on different islands. First introduction of Elaeidobius kamerunicus Faust had been done from North Sumatra to Seram Island on 23 September 2013. The introduction was performed on larva and pupa stadium in 4-5 days post anthesising of male inflorescences. The introduction of E. kamerunicus using plywood boxes has an average risk of death by 7.89% at 6 days delivery period. Observation before releasing of the weevils showed that this insect was not detected in both of oil palm male and female flowers and the oil palm fruit set was very low approximately 11.27%. For about 500 weevils/ha were released in Marnuhu estate and could be developed into 362,401 weevils/ha in 5 months with 97.86% of oil palm sex ratio. The oil palm fruit sets were increased after 1 and 2 months introduction, 53.70% and 75.56 %, respectively. The lower sex ratio of oil palm or the more availability of male inflorescences make growth of E. kamerunicus population became faster and the greater number of weevils that visiting anthesising of female flowers make the higher value of oil palm fruit set.

The DEVELOPMENT OF Elaeidobius kamerunicus FAUST POPULATION AFTER INTRODUCTION AND THE IMPROVEMENT OF OIL PALM FRUIT SET IN SERAM ISLAND, MOLLUCAS, INDONESIA

2018 ◽  
Vol 24 (1) ◽  
pp. 47-55
Author(s):  
Agus Eko Prasetyo ◽  
Agus Susanto
Keyword(s):  
Sex Ratio ◽  
Oil Palm ◽  
Fruit Set ◽  
Average Risk ◽  
Palm Fruit ◽  
Male And Female ◽  
Risk Of Death ◽  
North Sumatra ◽  
Female Flowers ◽  
Elaeidobius Kamerunicus

Elaeidobius kamerunicus is the main pollinating agent in oil palm plantations in Indonesia today. The development of oil palm plantations in new areas requires introduction of these insects, moreover the new areas are located on different islands. First introduction of Elaeidobius kamerunicus Faust had been done from North Sumatra to Seram Island on 23 September 2013. The introduction was performed on larva and pupa stadium in 4-5 days post anthesising of male inflorescences. The introduction of E. kamerunicus using plywood boxes has an average risk of death by 7.89% at 6 days delivery period. Observation before releasing of the weevils showed that this insect was not detected in both of oil palm male and female flowers and the oil palm fruit set was very low approximately 11.27%. For about 500 weevils/ha were released in Marnuhu estate and could be developed into 362,401 weevils/ha in 5 months with 97.86% of oil palm sex ratio. The oil palm fruit sets were increased after 1 and 2 months introduction, 53.70% and 75.56 %, respectively. The lower sex ratio of oil palm or the more availability of male inflorescences make growth of E. kamerunicus population became faster and the greater number of weevils that visiting anthesising of female flowers make the higher value of oil palm fruit set.

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