Differences In Fertility Research Articles

The Conflict within and the Escalating War between the Sex Chromosomes

The Conflict within and the Escalating War between the Sex Chromosomes

Hispanic Familism Reconsidered: Ethnic Differences in the Perceived Value of Children and Fertility Intentions

Familism has been described as a cultural trait that might explain why the fertility of Hispanic women remains higher than non-Hispanic white women. Still, few studies have analyzed group differences in childbearing attitudes. This article focuses on two dimensions of childbearing orientation: social value of children and fertility intentions. Using the National Survey of Family Growth, we find limited support for the idea that familism undergirds differentials in fertility between native-born Hispanics and whites. However, for foreign-born Hispanics, there are some differences in the perceived value of children compared with whites, and these differences could contribute to fertility differentials.

Fertility Patterns of Child Migrants

This article examines the fertility of women who migrated as children to one of three OECD countries—Canada, the United Kingdom, and France—and how it differs from that of native-born women, by age at migration. By looking at child migrants whose fertility behavior is neither interrupted by the migration event nor confounded by selection, the authors obtain a unique perspective on the adaptation process as a mechanism that explains variation in observed foreign and native-born fertility differentials. The authors find patterns that are broadly consistent with the adaptation hypothesis—which posits that as migrants become accustomed to their host countries, their fertility norms begin to resemble those of the native population—and, on average, limited cross-national variation in fertility differentials. The effect of exposure to the host country, however, seems to vary by country of origin, a finding that underscores the importance of taking into account the heterogeneity of the foreign-born population.

A Home to Plan the First Child? Fertility Intentions and Housing Conditions in Italy

ABSTRACTIn Italy, the existing literature on the link between low fertility and people's socio‐economic status has been surprisingly silent about the potential role of housing. This study aimed at filling this gap. Are Italians who are better off in terms of housing security more likely to plan to have a first child in the short run? Our results suggest that there is a clear positive gradient between the fertility intentions of couples and the degree to which they feel secure about their housing situation. The positive gradient remained substantial after we controlled for the demographic and socio‐economic characteristics of the couple and after we adjusted the estimates for the presence of unobserved characteristics and we took into account the endogeneity between housing and fertility. This implies that, in Italy, the housing dimension should not be disregarded when studying fertility differentials. Copyright © 2012 John Wiley & Sons, Ltd.

Immigrant Fertility: A Comparative Study between Italy and Russia

AbstractIn this paper, we contribute to the analysis of fertility differentials between female migrants and the native‐born by examining the transition to first child using event history analysis. We use event history as a quantitative translation of the life‐course approach. The data examined are the Italian Families and Social Subjects (FSS) survey, conducted in 2003, and the Russian Parents and Children, Men and Women in Family and Society survey, conducted in 2004. We examine the data sets separately and contrast the results. The objective of the study is twofold. First, we seek to determine whether differences exist in the decision and timing of childbearing between native and immigrant women in Italy and in Russia. Second, we aim to compare the experiences of immigrants in the two countries, to determine whether there may be any commonalities inherent to the immigrant populations despite moving into widely different contexts. Our results suggest that the age profiles and marital status similarly affect the immigrant regardless of whether she is migrating to Russia or to Italy. In Italy, educational attainment is positively correlated with first‐birth intensities for immigrants – the opposite of what is observed for the native‐born. In Russia, education is not a significant determinant for immigrants. This leads us to the following conclusion: the similarity in the risk profiles of our immigrants into vastly different country contexts is more suggestive of immigrants following a distinct life course, with common risk profiles for bearing their first child, than assimilating or conforming to the native fertility patterns. Social capital in particular may play a different role in determining fertility patterns for immigrants, as it does for the native‐born.

Intergenerational effects of shifts in women’s educational distribution in South Korea: Transmission, differential fertility, and assortative mating

This study examines the intergenerational effects of changes in women’s education in South Korea. We define intergenerational effects as changes in the distribution of educational attainment in an offspring generation associated with the changes in a parental generation. Departing from the previous approach in research on social mobility that has focused on intergenerational association, we examine the changes in the distribution of educational attainment across generations. Using a simulation method based on Mare and Maralani’s recursive population renewal model, we examine how intergenerational transmission, assortative mating, and differential fertility influence intergenerational effects. The results point to the following conclusions. First, we find a positive intergenerational effect: improvement in women’s education leads to improvement in daughter’s education. Second, we find that the magnitude of intergenerational effects substantially depends on assortative marriage and differential fertility: assortative mating amplifies and differential fertility dampens the intergenerational effects. Third, intergenerational effects become bigger for the less educated and smaller for the better educated over time, which is a consequence of educational expansion. We compare our results with Mare and Maralani’s original Indonesian study to illustrate how the model of intergenerational effects works in different socioeconomic circumstances.

Natural selection among coastal populations of India: Trend and extent

Background: Coastal populations have always been exposed to socio-cultural and natural vulnerability. The correlates between these coastal populations and their selection potentials have not been previously described.Aim: To describe selection potentials, their trend and extent among coastal and non-coastal populations of the Indian continent.Subjects and methods: Data on fertility and mortality differentials among five coastal populations were collected from 448 women of Orissa and Goa. Selection potential was computed. In addition, 48 studies among 100 different populations of India were reviewed for similar parameters, for comparison.Results: Total index of selection (It) varied from 0.221–0.417 in the population of Orissa; whereas the population of Goa showed a moderate index of selection. Regression analysis showed that among the coastal population the contribution of index of mortality (Im) is higher (92.5%) in total selection index (It) as compared to non-coastal populations (56.4%). After 1991, there was a radical shift in the role of mortality in the entire region. Simultaneously, the selection intensity (It) has gradually declined.Conclusion: There is a significant difference in the extent and process of natural selection among coastal and non-coastal populations. Mortality is playing a greater role in the total selection intensity of coastal populations, although the trend is declining in the entire region and reversal in the roles of Im and index of fertility (If) is witnessed.

Persistence Of Income Inequality: Does Child Mortality Matter?

Many developing countries are afflicted by persistent inequality in the distribution of income. While a growing body of literature emphasize differential fertility as a channel through which income inequality persists, this paper investigates differential child mortality - differences in the incidence of child mortality across socioeconomic groups - as a critical link in this regard. Using evidence from cross-country data to evaluate this linkage, we find that differential child mortality serves as a stronger channel than differential fertility in the transmission of income inequality over time. We use random effects and generalized estimating equations techniques to account for temporal correlation within countries. The results are robust to the use of an alternate definition of fertility that reflects parental preference for children instead of realized fertility.

Social Mobility and Demographic Behaviour: Long Term Perspectives

Abstract We introduce a collection of papers that examine interactions between demographic behavior and social mobility via analysis of historical and contemporary longitudinal, individual- and household-level socioeconomic and demographic data. authors originally presented these papers at The International Seminar on Social Mobility and Demographic Behavior: A Long Term Perspective held at the California Center for Population Research at UCLA in December 2009, and organized on behalf of the IUSSP Scientific Panel on Historical Demography. We convened the meeting as a means of promoting the use of historical demographic data to address a topic of contemporary relevance that has been the subject of much attention lately: how the inter-generational transmission of socioeconomic status and socioeconomic differentials in demographic behavior interact to shape patterns of inequality over the long term. papers here focus specifically on relationships among fertility, marriage, migration, and social mobility. 1. Introduction Demographic behavior and social mobility interact. Such interactions occur across and within generations. Across generations, household demographic context and socioeconomic status jointly influence demographic outcomes and socioeconomic attainment chances in adulthood. Within generations, demographic behaviors such as marriage and childbearing affect attainment chances, and socioeconomic status affects demographic outcomes such as marriage, childbearing, and mortality. At the macro-level, socioeconomic differentials in demographic behavior and demographic differentials in socioeconomic attainment interact to shape long-term trends in population composition (Mare and Maralani 2006). Among the relevant processes, demographic influences on socioeconomic attainment and the interactive influence of patterns of demographic and socioeconomic differentials on population composition have received the least attention. influence of family socioeconomic status on the socioeconomic attainment of the next generation is a long-standing preoccupation in the study of social stratification. influence of individual socioeconomic status on various demographic outcomes has been a long-standing interest in demography as well, but interest in the influence of family demographic context on socioeconomic attainment is more recent. Most reflect interest in the implications for attainment chances of recent increases in the diversity of family structures in developed countries (McLanahan and Percheski 2008). Studies of how socioeconomic differentials in demographic behavior and demographic differentials in socioeconomic attainment interact to shape trends in population composition are even more recent (Mare and Maralani 2006). Along these lines, historical demography and historical social mobility as areas of inquiry have, until recently, been largely separate. They intersected only insofar as considering historical studies of the determinants of demographic outcomes such as marriage, reproduction and death included socioeconomic status as an explanatory variable. Thus, we have numerous studies of socioeconomic differentials in mortality and fertility; for example, Bengtsson, Campbell, and Lee (2004) and Tsuya et al. (2010). Historical studies of social mobility have largely focused on inter-generational mobility, especially the influence of parental socioeconomic status. To some extent, this separation reflected the fact that historical databases of the requisite size and detail were, until recently, not widely available. New historical databases offer the prospect of integrating the study of social mobility and demography. Many of the longitudinal household- and individual-level population databases used in recent studies of historical demography are especially well-suited to the investigation of interactions between demographic behavior, social mobility, and population composition. …

A quantification of the effects of erosion on the productivity of purple soils

Research on the effects of soil erosion on soil productivity has attracted increasing attention. Purple soil is one of the main soil types in China and plays an important role in the national economy. However, the relationship between erosion and the productivity of purple soils has not been well studied. The purpose of this research was to determine if soil depth, which is dependent on the rate of erosion, has an influence on crop yield and growth. Plot and pot experiments at different soil depths were performed. Results indicate that soils from different parental materials had different growth features and crop yields due to the differential fertility of the derived soils. The yield reduction rate increases exponentially with the depth of eroded soil (level of erosion). The yield reduction rate per unit eroded soil horizon (10 cm) is approximately 10.5% for maize and wheat.

Partitioning sexual selection into its mating success and fertilization success components.

Postcopulatory sexual selection due to sperm competition and/or cryptic female choice has been documented in a diversity of taxonomic groups and is considered a pivotal component of sexual selection. Despite this apparent importance, the relative contribution of postcopulatory fertilization success to overall sexual selection has not yet been measured in any species. Here, we used a laboratory-adapted population of the promiscuous fruit fly Drosophila melanogaster to partition the variance in male reproductive success into mating success (a major component of precopulatory sexual selection) and fertilization success (a major component of postcopulatory sexual selection). We found that fertilization success contributed nearly as strongly as mating success to a male's net performance in sexual selection, but that most of this postcopulatory component was attributable to variation in male mating order (the tendency to be the last male to mate a female). After adjusting for mating order, only ≈2% of the residual variation in male reproductive success was attributable to differential fertilization success. We found no correlation between male mating success and fertilization success in this system. Unlike natural populations of Drosophila, our laboratory population is adapted to a semelparous lifecycle, so our findings will be most applicable to other promiscuous species with strong sperm precedence and one short breeding period per year or lifetime. In these species, fertilization success may have as much influence on male reproductive success as mating success, but the timing of mating (mating order) may be the predominant factor contributing to variation in fertilization success.

Educational Expansion and the Role of Demographic Factors: The Case of West Germany

To what degree and extent is the educational distribution in successive generations affected by parental differential fertility and social inequalities in educational attainment? Lower educated women, for example, are likely to have more children than higher educated women, and the children of lower educated mothers are more likely to attain less education than the children of higher educated mothers. This may lead to a downward pressure on the average level of education in the next generation. The aim of this article is to quantify the role of these mechanisms for West Germany in the 20 th century. This is done by simulating the distribution of education under different scenarios: a reference scenario in which all rates correspond to the empirically observed rates, a scenario that completely removes differential fertility, a scenario that completely removes inequality of educational opportunity, and a scenario that greatly increases the amount of differential fertility. The main finding is that the observed levels of inequality of educational opportunity and differential fertility are too small to result in a meaningful impact on the distribution of education in the subsequent generation. Both the first and the second scenario lead to only minor changes in the distribution of education compared with the reference scenario. However, in principle differential fertility could have a noticeable effect. This is illustrated by the results from the last scenario in which fertility of the lowest educated women is greatly increased. In such an extreme but not impossible society the average education would be considerably lower than in the reference scenario.

Differential Reproductive Success in the Historic Populations of Sandžak

The Balkan region is in a state of instability in the aftermath of Kosovo's independence, vulnerable to both inter- and intra-ethnic conflicts. Native Muslim populations in the Balkans continue to grow much more rapidly than non-Muslims. This paper attempts to assess maternal descendant-leaving success in 120 Muslim and Christian Orthodox women born between 1880 and 1924 in the Serbian multiethnic region of Sandzak. Differential fertility among ethnic groups is linked to the differences in religious affiliation. The paper will try to answer questions about the impacts of particular political and economic conditions on reproductive and lineage success for the two populations.Key Words: Balkans; Differential reproduction; Muslims; Christians; Sandzak; Serbia.Worldwide, religiosity-fertility links are a near-universal characteristic of today's cultures (Kaufmann 2008). In particular, individuals inclining to dogmatic and traditional religious beliefs out-reproduce those with more secular worldviews. Differential fertility among ethnic groups is linked to the differences in religious affiliation (Cvorovic 2012). Demography appears to be important for the historical rise and decline of religions because more than most other cultural traits, religion is transmitted within families (Steadman and Palmer 2008). The ability of traditional religious beliefs, values and behaviors to be repeatedly transmitted from ancestors to descendants enables them to influence the descendant-leaving success of individuals over many generations (Steadman and Palmer 1997). For instance, recent demographic reports indicate that native Muslim populations in the Balkans continue to grow much more rapidly than non-Muslims (Kettani 2010).An application of evolutionary theory to demographic data and human life history offers insights not only into the past, but also into modern problems, both large scale and urgent (Clarke and Low 2001, Wilson 1999). This paper attempts to assess maternal descendant leaving success of 120 women (52 Muslims and 68 Christian Orthodox) born between 1880 and 1924 in the Serbian southern region of Sandzak. Sandzak is a multi-ethnic region, a largely mountainous border area between Serbia and Montenegro, bordering Kosovo to the south-east and Bosnia and Herzegovina to the west, containing the largest concentration of Serbian Muslims, recognized as Bosniacs. At present, as in the past, Sandzak remains vulnerable to both inter- and intra-ethnic conflicts. Re-affirmations of national identity and presence by Christian Orthodox Serb and Muslim-Bosniac ethnic groups, mainly with respect to religion and language, threaten to prompt future resentment. In fact, the Balkan region is in a state of instability in the aftermath of Kosovo's independence, and thus areas of potential flux such as the Sandzak should be monitored closely (Morrison 2008:1).Vanhanen (1999) argued that ethnic conflict may appear by the mere existence of ethnic diversity, regardless of governmental style or policies. For instance, in the former Yugoslavia, ethnic competition and subsequent violence marked the past. In a multi-ethnic society, competition may include warfare between different ethnic groups over territory. Control of territory traditionally facilitated reproduction and development of cultural and economic traditions, hence the benefit of ethnic control is obvious - it aids a particular group to carry on its genes and traditions into subsequent generations (Cvorovic 2004). The problem of changing composition of the population along ethnic and regional lines was crucial in the Balkan crisis (Apostolov 2010).In the Yugoslav federation, built after the Second World War, ethnic conflicts were suppressed by the communist dictatorship. However, the federal state establishment also created the conditions for separation of the neighboring ethnic groups and creation of new ethnic identities which, along with changing population growth rates, inevitably led to conflict. …

Natural selection in a population group of Andaman and Nicobar Islands.

Background:Natural selection is a continuous process that operates in populations to weed out deleterious genes and preserve the genes that increase the chances of survival, procreation, and multiplication. The fitness of a population group is measured in terms of its differential fertility and mortality. These are the most fundamental events through which the natural selection is operative. Selection intensity, which is a measure of the fitness of a population, is expressed in terms of differential fertility, and differential mortality, assuming that the heritability of fitness is complete and that the birth and death rates are all selective. These indices are influenced by a number of socio-cultural conditions, religious, ethnic, and environmental factors which have been studied by different researchers in different parts of the world, including India.Objective:In this paper, an attempt was made to study the index of total selection, index of selection due to mortality, and index of selection due to fertility among the Andaman Indians, an island population of Andaman and Nicobar Islands and we highlight the variability of selection intensity in different ecological zones of India, namely the island, coastal, plains and plateau, Himalayan region, and the desert ecologies.Materials and Methods:Data were collected on pre-designed questionnaire, from women aged 40 + years, on various demographic parameters.Results:The value of the Index of Total Selection was found to be 1.263, the component due to fertility was 1.020, and that of mortality was found to be 0.120

Demography and Modernization as the Major Determinants of Religious Belief

Using a sample of up to 62 countries, this study finds that differential fertility influences trend lines in the prevalence of theistic religious belief at the country level. High religiosity of females relative to males is an additional, though less consistent, predictor. These effects are demonstrated on the background of two other causal influences: Recovery from communist rule predicts a rising trend, and indicators of economic, social and cognitive development predict a declining trend. Several alternative hypotheses about the determinants of religious trends receive no support.

Wpływ zróżnicowanego nawożenia fosforem i potasem na odżywienie pszenżyta ozimego w fazie krytycznej oraz plon ziarna

Research was carried out in the years 2008-2010 on the objects of stationary experiment established in 2000 at the Research Station Brody - Poznań University of Life Sciences. Hortenso variety of winter triticale was cultivated in the conditions of one-factor experiment. The factor investigated was a differential level of mineral fertilization with phosphorus and potassium. The aims of the study comprised: (1) determination of winter triticale response with reference to the optimal fertilizer rate as well as reduced levels of P and K fertilization, (2) evaluation of winter triticale nutritional status at the stage BBCH 31 in the conditions of differential fertilization with phosphorus and potassium, (3) assessment of yield diagnostic methods based on nutritional status and biomass produced during the analyzed development stages. Triticale response in the experimental conditions indicated that this plant is more sensitive to potassium deficiency when compared with phosphorus. Evaluation of plant nutritional status with the use of PIPPA software indicated that plant yield was constrained by deficiency of numerous elements. In the group of mineral nutrients limiting triticale yield, the effects of calcium, magnesium and potassium were most evident.

Les disparités géographiques de fécondité en France

Les disparités régionales de fécondité en France perdurent. La fécondité est la plus élevée dans les Pays de la Loire et dans le Nord - Pas-de-Calais. Elle est la plus faible dans le Sud-Ouest de la France. Ce schéma diffère peu de celui qui prévalait dans les années du baby-boom, il y a 50 ans. Cependant, la fécondité de l’Île-de-France est désormais supérieure à la moyenne nationale, alors qu’elle était la région de plus faible fécondité.Au niveau infrarégional, la fécondité est plus basse dans les zones les plus urbanisées, surtout dans des régions où une part importante de la population reste rurale. Ces disparités entre zones rurales et zones urbaines, de même que les disparités entre villes-centres et banlieues, renvoient aux disparités relatives aux structures familiales. Ainsi, à Paris, la part de personnes seules parmi les femmes en âge de procréer est forte et la fécondité est faible.Quelques départements de la banlieue parisienne où la présence immigrée est importante ont une forte fécondité. Mais d’autres, comme la Mayenne, comptent peu d’immigrés et ont aussi une fécondité élevée. L’inverse est également vrai : une forte présence immigrée ne s’accompagne pas toujours d’une fécondité forte. Dans toutes les régions, les femmes les moins diplômées ont une fécondité plus forte. Mais l’écart entre les plus diplômées et les moins diplômées varie : très faible dans l’Ouest de la France, il est marqué dans le Nord - Pas-de-Calais.Au total, ces différents facteurs n’expliquent qu’une faible part des disparités régionales, finalement assez durables.

Age structural transition in South Africa

This chapter deals with the current age structure and the age structural transition (AST) underway in South Africa. We have used the national Census data for 1996 and 2001 and the Community survey data for 2007. In 2007, 31 percent of the population was enumerated below 15 years of age, 64 percent between 15- 64 and 5.4 percent 65+ implying the early stages of aging process. The median age in 2007 is 24.3 years, increased from 23 years in 1996. The proportion of young dependents is declining whereas that of the economically active and aged populations are increasing. Generally, the Black population appears younger and the Whites older. The other two ethnic groups are placed in the middle. This is, perhaps, a reflection of the differential fertility across the ethnic groups. The proportion of labour force population in 2007 is the highest for Asians & Indians followed by Whites; and the lowest for Blacks. So far as the proportion of the aged is concerned, Whites lead relatively high (12.4 %) as compared to coloured and Black population groups. During 1996-2007, the age structural transition for the total population is only marginal in South Africa. The median age of the total population grew from 23 years to 24.3 years, an increase of 5.6 percent. The female median age grew from 24.5 to 25.2 years, slightly better than that of males. The old age population has increased by 12.5 percent during the same period along with the global trend of female advantage. Again, the labour force population has increased by 5.5 percent. AST is highest for the white population, followed closely by Asians & Indians. This calls for continued higher investments in primary and secondary education, health care service delivery including reproductive health and social security. Again, for a country like South Africa where unemployment is quite high, the enormity of labour force (64%) has to be viewed seriously. Rapid employment generation, especially for the weaker groups, is the key. Further, one fifth (20.4 %) of the population is in the 15-24 years age group which is the target group for tertiary education. The slow process of AST among Black population warrants for preferential resource allocations especially in the areas of reproductive health and employment.

TLR1 polymorphisms in Europeans and spontaneous pregnancy loss

Toll-like receptors (TLRs) are critical components of the pathogen recognition by the host innate immune system. Recently it has been shown that TLR1 is under evolutionary pressure in Europeans. This involves the positive selection of the nonsynonymous TLR1 1805G variant in Europeans, although this is associated with poor TLR1 response and unfavorable prognosis in various infections. In terms of natural selection, differential fertility is another mechanism, independent of infection susceptibility, that may explain the polymorphism pattern observed for TLR1. To test this hypothesis, we assessed the correlation of two TLR1 SNPs (T1805G and G239C) with spontaneous pregnancy loss in a case–control study that included 132 spontaneous pregnancy loss patients and 142 control volunteers. Similar allele frequencies of T1805G were observed between cases and controls, but GG genotype tended to be associated with pregnancy loss (OR 1.91; 95%CI 1.03, 3.53). No differences were observed for the TLR1 G239C SNP. Our findings showed slight differences in the distribution of T1805G variants in women with pregnancy loss, but these were not indicative of a protective effect of the TLR1 1805G allele for this fertility disorder. Although our hypothesis was not proven, potential effects of TLR1 polymorphisms on pregnancy outcome have been suggested, and future studies in larger cohorts are warranted.

HOW DEPRESSED? ESTIMATES OF INBREEDING EFFECTS DURING SEED DEVELOPMENT DEPEND ON REPRODUCTIVE CONDITIONS

Inbreeding depression can reduce the performance of offspring produced by mating between relatives, with consequences for population dynamics and sexual-system evolution. In flowering plants, inbreeding depression commonly acts most intensely during seed development. This predispersal component is typically estimated by comparing seed production following exclusive self- and cross-pollination, but such estimates are unbiased only if seed production is limited by ovule availability, rather than by pollen receipt or seed-development resources. To overcome this problem, we propose experimental and statistical methods based on a model of ovule fertilization and seed development that accounts for differential fertilization by self- and cross-pollen, limited ovule viability or receptivity, differential survival of self- and cross-zygotes and limited resource availability. Simulations illustrate that the proposed methods eliminate bias in estimated predispersal inbreeding depression caused by pollen limitation and can improve estimates under resource limitation. Application of these methods to two orchid species further demonstrates their utility in identifying and estimating diverse influences on reproductive performance under typical conditions. Although our theoretical results raise questions about the reported intensity of predispersal inbreeding depression, our proposed methods guard against bias while also providing insight into plant reproduction.