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Double-yolked (DY) eggs are a rare phenomenon in domestic poultry and game birds, generally ~1-2% of the eggs are DY over the laying cycle. The production of such eggs is influenced by several fact...

OBJECTIVE To minimize twin birth rate by establishing an elective single cleavage embryo transfer strategy based on a twin live birth prediction model from fresh double cleavage embryos transfer (cleavage DET) patients. METHODS A total of 2478 patients underwent fresh cleavage DET in Nanjing Tower Hospital were enrolled to establish the twin live birth prediction model by logistic regression analysis and the cutoff value was calculated by ROC curve. Another 300 fresh cleavage DET patients and 550 cleavage single-embryo transfer (SET) patients were selected to testify the sensitivity, specificity and usefulness of this model. RESULTS The twin live birth probability (TLBP) = eX /(eX + 1), e is a natural logarithm, X = -1.763 - (0.319 × female age) + (0.329 × endometrial thickness) + (0.282 × the number of transferred top embryos) - (0.314 × previous transfer times), and the cutoff value of TLBP was 24.2%. The sensitivity of this model for predicting twin live birth was 75.6%, while the specificity was 52.5% in the external validation of 300 DET patients. Furthermore, the validation of 550 SET patients showed that the live birth rate of TLBP value positive patients was significantly higher than that in negative patients (54.3% vs. 35.5%, p

Pheromones are important components of insect reproductive biology. They play a broader role in praying mantid behaviour by aggregating individuals and facilitating sexual recognition. Female calli...

Long-term intake of water with high content of trihalomethanes (THMs) such as chloroform (CHCl3) is hazardous for human health. Some studies have shown that clinical effects of THMs in drinking water may be yet observed to doses lower to standard limit. In our study, we performed a meta-analysis to assess both the mean concentration of CHCl3 in Iranian drinking water and the relative health effects by long-term exposure to safe dose of CHCl3 in the male and female age groups and in female categories. We applied the Target Hazard Quotient (THQ) for the evaluation of the noncarcinogenic risk of CHCl3. Meta-analysis (14 studies) showed that the average concentration of CHCl3 was 24 µg/l (95%CI:18.1–30.1 µg/l), I2 = 99.88, p non-pregnant and non-lactating females age 4–15 (0.071) > pregnant (0.071) > lactating (0.043). The THQ in the females was higher than males, non-significantly (p >.05). Except Mazandaran province, in other provinces both males and females, for all age groups, were not exposed to significant risks by non-carcinogenic exposure of CHCl3 in drinking water (THQ

By constructing a gender wage gap evolution model, this paper examines the source and evolutionary process of gender wage inequality from a theoretical perspective. The purpose of this study is thoroughly investigating the factors affecting the gender wage inequality from the perspective of gender discrimination and variations in non-gender endowments. Based on the Chinese Household Income Project Survey Data, this study indicates that: (1) since companies continue to re-evaluate the gender endowment value of gender, the gender wage inequality exhibits an endogenous sustainability and self-reinforcing effect. (2) The gender wage gap of urban residents is derived mainly from the top tier of wages, while the gender wage gap of the migrant people is mainly determined from the bottom rung of wages. (3) Female age has a ‘U-curve’ impact on gender wage inequality from the standpoint of non-gender endowment differences, and the female age has an ‘inverted U-curve’ impact on gender wage inequality as a re...

The life table parameters of the two-spotted spider mite (TSSM), Tetranychus urticae Koch, were determined on seven eggplant cultivars (“Isfahan”, “Dezful”, “Shend-Abad”, “Neishabour”, “Bandar-Abbas”, “Jahrom” and “Borazjan”) at 25 ± 1°C, 60 ± 5% RH and a photoperiod of 16:8 (L:D) h. The age-stage, two-sex life table and the traditional female age-specific life table were constructed by using demographic data. There was a significant difference between the duration of different life stages of TSSM on different eggplant cultivars. Using the age-stage, two-sex life table, the intrinsic rate of increase (r) on the above-mentioned cultivars varied from 0.022 day−1 on “Neishabour” to 0.157 day−1 on “Isfahan”. The value of the net reproductive rate (R0) of TSSM on different eggplant cultivars varied from 1.425 offspring on “Neishabour” to 11.585 offspring on “Isfahan”. Furthermore, the values of the gross reproductive rate (GRR) were significantly different on the tested cultivars, and the lowest and highest va...

This paper examines age at first marriage for women and spousal age gap as an indicator for female agency from 1950 to 2005. Using a dataset of 77 LDCs this paper seeks to explore which variables determine differences at a country level in marriage patterns. We look at the influence of urbanisation, education, percentage population of Muslim faith, and family type. We find that education is a key in determining at what age women marry, having as would be expected a positive effect on age at first marriage and depressing spousal age gap. Urbanisation is significant, with a positive effect on age and negative on spousal age gap, although the effect is not very large. The percentage Muslim variable depresses female age at first marriage and increases spousal age gap but only when family type is not controlled for. The initially strong negative effect of percentage population Muslim over the period under consideration on age of first marriage has decreased, which raises some interesting questions about the ro...

In this article, some factors were evaluated for their impact on embryo morphokinetics during assisted reproductive technology (ART) cycles. We detected significant differences in the fourth cell division time (t5) of embryos obtained after controlled ovarian stimulation in long GnRH agonists and GnRH antagonist protocols. We also found that higher gonadotropin dose may slow down the development of embryos. However, both male and female age, the number of oocytes and number of normal forms of sperm in the ejaculate did not affect the kinetic parameters of embryo development. Further research is needed to identify all the spectrum of factors, which can affect the rate of embryo development.

To evaluate the influence of female age and cause of infertility on the outcome of controlled ovarian hyperstimulation (COH) and intrauterine insemination (IUI), we studied 2717 COH cycles in 1035 subfertile couples. The cumulative clinical pregnancy rates were 39% and 58% after three and six COH cycles, respectively. The cumulative pregnancy rate significantly decreased with maternal age and differed by cause of infertility. The cumulative pregnancy rate continued to increase with an increase in COH cycle number up to the third, or forth cycle, in patients with mechanical and combined infertility, respectively, and in up to the second cycle in patients aged 40 years or more. These findings provide treatment guidelines for clinicians in determining the likelihood of treatment success and the point at which to proceed to the next treatment strategy.

In contrast to East and South-east Asia, changes in marriage patterns have played a small role in reducing fertility in South Asia. While age at marriage for women has risen, it remains early, with the exception of Sri Lanka, and change has been slow. Except in Sri Lanka, the region has shown few signs that there will be a sizable population that will never marry. South Asia's marriage patterns reflect its cultural context and lesser socio-economic change but their precise effect is not simple or always predictable. The paper examines these issues in Bangladesh, where age at marriage is very early, and Sri Lanka, where it is much later. The study areas, Dhaka city and south-western Sri Lanka, are ones of great economic and social change. A particular examination is made of the way in which changes in the arrangement of marriage affect age at marriage.

This paper explores whether sexual orientation has a significant effect on men and women's perceptions of attractiveness of 36–41-year-old women, and tests the validity of inversion theories of homosexuality. Previous research has established that female age is more salient to men than to women when judging female attractiveness. A web-based survey was implemented, attracting 135 male and 150 female British and American participants. They rated the age and attractiveness of 13 female images. Separate MANCOVAs were performed to analyse the effect of participant sex and sexual orientation on the perception of attractiveness. Consistent with prior research, men's ratings of attractiveness were lower than those of female participants. Sexual orientation was not found to be a significant variable in men's perceptions of attractiveness. The attractiveness ratings given by homosexual and bisexual women were significantly lower than those of heterosexual women. Sexual orientation may therefore be relevant to the ...

Capsule Young birds are less likely to have high reproductive success compared with older ones because of a lack of several skills influencing breeding performance. Aims To test the ‘constraint’ hypothesis by investigating the effect of male and female age on reproductive performance of a Bluethroat Luscinia svecica population. Methods We compared two age-classes (yearling versus old), breeding for the first time at Guerande salt-pans, France, by evaluating arrival dates on breeding site, territory quality, laying dates, clutch size and egg size, delay before re-nesting, breeding performance, feeding rate at two different nestling periods (on days 4–5 and 10–11 after hatching) and nestling body condition. Results Our results clearly demonstrated an age effect on reproductive performance for both males and females: young breeders were less likely to fledge young. In older males, improvement of reproductive success was related to feeding rate during the first nestling period. For females, timing of breeding...

This work uses Durkheimian societal integration measures and proxies for the culture of suicide to test for differences in the impact of predictors on suicide rates of younger and older women and for change in the effect of predictors over time. Four integration measures (female labor force participation, divorce rates, fertility, and religious book production) retained the same sign in all age groups, and their unstandardized regression coefficients typically increased as the mean suicide rate of the age group increased through ages 55–64, before declining. The culture of suicide (measured with attitudinal data or regional proxies) had much stronger effects on the explained variance of women 65 and older than on women 15–64. With controls on societal integration and region, the pattern of declining female suicide rates after 1970, as predicted by “institutional adjustment” theorists, did not appear.

This study was conducted to evaluate the current results of standard in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) in the elderly (or = 40 years of age) female population. Oocyte recovery, fertilization, embryo transfer, pregnancy and cumulative pregnancy rates were assessed. The results were analyzed for: the entire elderly population; the standard IVF group (group 1); all those in the ICSI group (group 2); and ICSI for severe male-factor category (group 3). A total of 330 IVF and 158 ICSI treatment cycles were carried out in 249 women. Forty-five (9.2%) clinical pregnancies were achieved. This rate was not statistically different from those achieved for groups 1, 2 and 3 (9.1%, 9.5% and 6.8%, respectively). The cumulative pregnancy rate for a total of five cycles was 19.2% and 26.4% for groups 1 and 2, respectively. For those who started their treatments ator = 40 years, the cumulative pregnancy rate for three cycles was 26.5% and 36.5% in groups 1 and 2, respectively. These results clearly demonstrate that female age is a major success determinant, with similar influence on both standard IVF and ICSI therapy modalities.

The associations between reproductive effort, as assessed by variation in natural clutch size and experimentally altered brood size, breeding success, and prevalence of blood parasite infections were studied in blue tits, Parus caeruleus. Females infected with blood parasites during incubation had laid significantly smaller clutches than non-infected females, irrespective of female age and laying date. Infected and non-infected females did not differ in the length of incubation delay, the time spent incubating eggs, or in fledging success. However, nestlings reared by females that had infections during incubation fledged in significantly poorer condition than nestlings reared by non-infected females. These findings are consistent with the interpretation that parasites had a negative impact bn their blue tit hosts, but they do not exclude the possibility that the prevalence of haematozoans and reduction in reproductive output (clutch size) and success (fledging condition) were independently triggered by some third factor (e.g., energetic stress caused by variation in territory quality). However, the prevalence of parasites at day 14 posthatch was related to experimentally altered brood size: adult females and males rearing enlarged broods were more likely to be infected than those rearing control or reduced broods, although the opposite was true for juvenile females and males. From our results, we suggest that a naturally low reproductive output (clutch size) may be an indicator of low individual quality, and that there may be a trade-off between reproductive effort and immunocompetence.

Growth rate estimates were obtained for elephantfish using length‐frequency and tag‐recapture data from the east coast of South Island during 1966–88. Elephantfish hatch from egg cases at about 10 cm fork length (FL) during May‐July. Females grow faster than males after their first year and growth is fastest in summer. In 1966–68, elephantfish in Pegasus Bay grew faster than in Canterbury Bight, resulting in modal length differences that were maintained for the first 3 years of life. This suggests there are at least two distinct juvenile nurseries. Maximum observed lengths were 76 cm FL for males and 97 cm FL for females. Length‐frequency analyses identified 5–8 male age classes and 8–9 female age classes, but longevity probably exceeds these values. Growth rates of 0+ elephantfish in Pegasus Bay in 1983—84 and Canterbury Bight in 1988 were 33–56% greater than in 1966–68. The faster growth rate meant male age at maturity was 4+ in the 1960s and 2+ to 3+ in the 1980s. If female length at maturity ...

Marriage in colonial North America was notable for being early (for women) and market by low percentages never marrying. This was different from the distinctive northwest European pattern of late marriage and high proportions never married late in life. But the underlying neolocal family formation behavior was the same in both colonial North America and the areas of origin of this population. Thus, Malthus was correct. Abundant resources rather than basic behavioral differences made early and extensive marriage possible in the colonies. Between 1800 and the present there have been long cycles in nuptiality. Since about 1800, female age at first marriage rose from relatively low levels to a peak around 1900. Thereupon a gradual decline commenced with a trough being reached about 1960 at the height of the baby boom. There then began another, and rapid, upswing in female marriage age. Proportions never married at ages 45–54 replicated these cycles with a lag of about 20–30 years. Since 1880 (when comprehensi...

Summary This study, using samples of 300 of each sex from the 1973 APA Directory, replicated 1948 research showing female age concealment and again found a significant (p < .001) sex difference. With BA dates yielding assumed age, 1948 data showed principally older women concealing. In 1973, there was significant (p < .01) concealment increase among the younger women, but age still had an influence, judging from actual ages of 35 concealers returning a questionnaire and from assumed ages of .55 nonreturning concealers; all women were significantly older (p < .01) than men; and returning concealers, contrasted with men and women revealers, received BA's when significantly older (p < .01; p < .02). Compared to 1948, both sexes were significantly older (p < .01), but female time distance from the BA was significantly longer (p < .02) than male. All such factors may augment concealment. There was also a significant (p < .01) geographical-concealment association, itself highly related to age. It is hypothesize...

The timing of fledging in a population of nuthatches, breeding mainly in natural holes, was studied in 5 successive breeding seasons, with a total of 70 successful broods. Fledging date varied significantly among years, and was correlated with female age and body size, but not male age or body size. Fledging dates varied significantly among territories, but the responsible factors are not clear and may not be related to other aspects of territory quality. First-year females immigrating in winter or spring bred later than residents, which may be due to an indirect effect of territory quality. There is no evidence for an effect of duration of the pair-bond nor of changes in nest site between years. An important advantage of breeding early in nuthatches is that juvenile birds start to establish territories within weeks of fledging, and early young have a better chance of obtaining a high quality territory.

In a sample of 210 couples, 29 had a natural child within 71/2 years of adoption. Excluding cases of absolute sterility and of no pregnancy on medical recommendation, post-adoption births were found to be associated with idiopathic infertility, having borne child(ren) before adoption, female and not male subfertility, and female age less than 36 years. Neither duration of infertile marriage before adoption nor the first four years thereafter were related to post-adoption fertility. However, four years after adoption child bearing was found to “taper off”, independently of mothers' ages and duration of marriages. The findings could be interpreted as giving an indirect support to the hypotheses that there is a causal connection between adoption and subsequent child bearing.

Some female Eiders breed when they are two years old, and most do so by the time they are four. Young birds lay later, have smaller clutches and are lighter in weight at the start of incubation than older females.

A research study of IUD insertions and acceptor characteristics is conducted from data on 1088 insertions in one hospital and 170 in a second hospital during the period from July 1965 to March 1967 in the city of Trivandrum in the state of Kerala in South India. Research results are summarized as follows: 1) An analysis of female age composition indicates that 80% are between 20 and 34 years and 84% are below 35 years; 2) Kerala women adopt the IUD earlier than their counterparts in other areas as indicated by the fact that 58% of the women in the research group had 3 or less children at the time of IUD insertion; 3) The IUD was more popular among Hindus than among Christians and Moslems; 4) One third of the number of IUD acceptors adopted the IUD within 6 months of the last childbirth; 5) Information on the interval between the last menstrual period and IUD insertion was available in 61% of the cases and showed that only 12% were within 7 days; and 6) After one year 91% of the cases of IUD were found active. This very high percentage in contrast to other study results was probably traceable to the intense interest taken by the hospital staff in the program.