Since determination of factors influencieng childbearing delay can provide convenient approaches to prevent fertility decline, nowadays studying this issue is an important issue for demographers and it is also emphasized by planners and politicians. The aim of this study is to evaluate factors influencing first birth interval among 458, young Iranian married women in Tehran province. In this cr...

Aggression and social spacing were studied in 14 light horse mares and their foals living at pasture. Focal samples were collected on each mare–foal dyad for 6 to 10.5 h from 2 months of foal age until weaning at approximately 4 months of age. Observations on foals continued until approximately 6 months of age for 7.5 to 10.5 h per foal. Every 2 min the identities of all individuals within 5 m ...

OBJECTIVE To establish a method of estimating the proportion of women with a subsequent live birth after a well-defined time period in an open cohort of women referred to a tertiary recurrent miscarriage clinic. METHODS We performed a descriptive cohort study with register-based follow-up at a tertiary center for investigation and treatment of recurrent miscarriage in Denmark. All women with ...

The incidence of mongolism increases so remarkably with advancing maternal age that it hardly seemed necessary to earlier workers to know the maternal age structure of the population from which their cases were drawn (Shuttleworth, 1909; Brousseau, 1928; Engler, 1949), or to ensure that the control group was representative (Jenkins, 1933; Rosanoff and Handy, 1934; Lahdensuu, 1937; Bleyer, 1938;...

Many mammalian societies are structured by dominance hierarchies, and an individual's position within this hierarchy can influence reproduction, behaviour, physiology and health. In nepotistic hierarchies, which are common in cercopithecine primates and also seen in spotted hyaenas, Crocuta crocuta, adult daughters are expected to rank immediately below their mother, and in reverse age order (a...

Abstract Rank-based measures of intergenerational mobility are generally justified by their invariance to changes in inequality. However, I show that whenever the source inequality is uncorrelated parent ranks, such as cases gender and birth order, increasing equality leads a fall rank measured correlation. develop method ex-post quantify importance for measurement using cross-sectional income ...

OBJECTIVES The University of Wisconsin Population Health Institute has published the County Health Rankings since 2010. These rankings use population-based data to highlight health outcomes and the multiple determinants of these outcomes and to encourage in-depth health assessment for all United States counties. A significant methodological limitation, however, is the uncertainty of rank estima...

OBJECTIVE To determine to what extent institutions carrying out in vitro fertilisation can reasonably be ranked according to their live birth rates. DESIGN Retrospective analysis of prospectively collected data on live birth rate after in vitro fertilisation. SETTING 52 clinics in the United Kingdom carrying out in vitro fertilisation over the period April 1994 to March 1995. MAIN OUTCOME...