نتایج جستجو برای: low fertility

تعداد نتایج: 1243891  

Journal: :Population studies 2003
John Bongaarts

This study summarizes patterns of educational differentials in wanted and unwanted fertility at different stages of the fertility transition. The data are from Demographic and Health Surveys in 57 less developed countries. As the transition proceeds, educational differentials in wanted fertility tend to decline and differentials in unwanted fertility tend to rise. An assessment of fertility pat...

2008
Peter McDonald

Introduction This paper addresses the issue of very low fertility in countries with advanced economies including its consequences and its causes. It ends with a discussion of policy approaches to reverse very low fertility. Very low fertility is defined as being fertility sustained for a long period below 1.5 births per woman. It is recognized that annual fertility rates are affected by changes...

2010
Rainald Borck

This paper studies the effect of cultural attitudes on childcare provision, fertility, female labour force participation and the gender wage gap. Cross-country data show that fertility, female labour force participation and childcare are positively correlated with each other, while the wage gap seems to be negatively correlated with these variables. The paper presents a model with endogenous fe...

2009
JOSHUA R. GOLDSTEIN TOMÁŠ SOBOTKA AIVA JASILIONIENE

Period fertility rates fell to previously unseen low levels in a large number of countries beginning in the early 1990s. The persistence of Total Fertility Rates under 1.3 raised the possibility of dramatic, rapid population aging as well as population decline. In an analysis of recent trends, we find, however, a widespread turn-around in so-called “lowest-low” fertility countries. The reversal...

A. Rahim A. Singh B.A. Ganaie N. Shah R. Sinha S.A. Lone,

Bull fertility may be defined as the process by which spermatozoa fertilize and activate the ovum and then support embryonic development. Bull fertility is a complex trait having relatively low heritability and plays a vital role for efficient production and reproduction of bovine. Various mechanisms involved in regulating bull fertility associated phenotype and reliable biomarkers are poorly d...

Journal: :Journal of andrology 2006
Arlindo A Moura David A Chapman Hasan Koc Gary J Killian

We evaluated the relationships between proteins in cauda epididymis fluid (CEF) and fertility scores of dairy bulls. Fertility was expressed as the percentage point deviation (PD) of bull nonreturn rate from the average fertility of all bulls at an artificial insemination center. The number of services for each bull ranged from 1074 to 52 820, and PD values ranged from +7.7% to -6.6%. CEF from ...

2013
Stuart Basten

Pacific Asia is currently home to some of the lowest fertility rates – and hence the fastest aging populations – in the world. This paper presents a systematic overview of both the reasons for this low fertility, and why it is unlikely to increase fertility significantly in the near future. As well as a comprehensive review of scholarly opinion, the paper examines the uniquely low fertility ide...

Journal: :Proceedings. Biological sciences 2012
Anna Goodman Ilona Koupil David W Lawson

Adaptive accounts of modern low human fertility argue that small family size maximizes the inheritance of socioeconomic resources across generations and may consequently increase long-term fitness. This study explores the long-term impacts of fertility and socioeconomic position (SEP) on multiple dimensions of descendant success in a unique Swedish cohort of 14 000 individuals born during 1915-...

2004
Filippo Miglior

Introduction Fertility is a very complex trait, difficult to define, to record and to evaluate all the factors that influence fertility. Fertility is strongly influenced by environmental effects and in part by genetics, the male for fertilization and the female for conception. In general, the fertility trait is hereditary but only to a small degree. There does however exist sufficient genetic v...

Journal: :Asia-Pacific population journal 1988
J Knodel N Chayovan C Frisen

Thailand is 1 of the third world countries in which a very substantial fertility decline has occurred during the last 2 decades. However, there has been some recent concern, based on fertility rates derived from 3 national contraceptive prevalence surveys conducted in 1978/1979, 1981, and 1984, that the fertility decline may have lost momentum at a level well above replacement fertility. New ...

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