Neutron star properties in the quark-meson coupling model

The effects of internal quark structure of baryons on the composition and structure of neutron star matter with hyperons are investigated in the quark-meson coupling (QMC) model. The QMC model is based on mean-field description of nonoverlapping spherical bags bound by self-consistent exchange of scalar and vector mesons. The predictions of this model are compared with quantum hadrodynamic (QHD) model calibrated to reproduce identical nuclear matter saturation properties. By employing a density dependent bag constant through direct coupling to the scalar field, the QMC model is found to exhibit identical properties as QHD near saturation density. Furthermore, this modified QMC model provides well-behaved and continuous solutions at high densities relevant to the core of neutron stars. Two additional strange mesons are introduced which couple only to the strange quark in the QMC model and to the hyperons in the QHD model. The constitution and structure of stars with hyperons in the QMC and QHD models reveal interesting differences. This suggests the importance of quark structure effects in the baryons at high densities.Comment: 28 pages, 10 figures, to appear in Physical Review

Fertility, Living Arrangements, Care and Mobility

There are four main interconnecting themes around which the contributions in this book are based. This introductory chapter aims to establish the broad context for the chapters that follow by discussing each of the themes. It does so by setting these themes within the overarching demographic challenge of the twenty-first century – demographic ageing. Each chapter is introduced in the context of the specific theme to which it primarily relates and there is a summary of the data sets used by the contributors to illustrate the wide range of cross-sectional and longitudinal data analysed

LABOR FORCE PARTICIPATION AND POVERTY STATUS AMONG RURAL AND URBAN WOMEN WHO HEAD FAMILIES

This paper examines differentials in the propensity to be living in poverty among women who head families with minor children. Characteristics of mothers are examined for four subgroups: residents of central cities, suburbs, small towns, and rural areas. Using Public Use Microdata Sample data from the 1980 Census, results are presented using Multiple Classification Analysis. After controlling for the effects of mother's race, marital status, education, work status, and ages of her children, single mothers in central cities and smaIl towns have the highest rates of poverty (48% and 45% respectively), closely followed by those in rural areas (41%). Suburban single mothers are least likely to live in poverty (33%). Copyright 1988 by The Policy Studies Organization.