Strengthening Africa’s Contributions to Child Development Research: Introduction

The articles in this Special Section are based on contributions to an SRCD-sponsored invitational conference held in Victoria, Canada, in February 2009. This introductory article establishes the rationale for focusing on Africa as part of an effort to advance a more inclusive science of child development, provides a brief overview of the thrust of the other articles in the section, describes 2 research capacity-building initiatives that emerged from the conference, and concludes with reflective perspectives on conceptual and methodological considerations for a future African child development field

Maternal literacy and health behavior: a Nepalese case study

This article addresses the question of whether literacy could be mediating the relationships of schooling to maternal health behavior in populations undergoing demographic transition. Recent studies in which literacy was directly assessed suggest a literacy pathway to demographic change. The literacy skills of 167 urban and rural mothers of school-aged children in Lalitpur District of the Kathmandu Valley of Nepal were assessed by tests of reading comprehension, academic language proficiency, health media skills and health narrative skill, as part of studies in the urban and rural communitiesthat included a maternal interview and ethnographic fieldwork on the contexts of family life, health care and female schooling. Regression analysis of the data indicates the retention of literacy skills in adulthood and their influence on health behavior; ethnographic evidence shows that selective bias in school attainment does not account for the results. Further direct assessment studies are recommended

Literacy as a pathway between schooling and health-related communication skills: a study of Venezuelan mothers

This article addresses the mechanisms by which women’s schooling might affect the survival and health of their children. A theoretical model is proposed in which academic literacy skills serve as a pathway between formal schooling and maternal health-related behaviors. The model is tested through multivariate analyses of interview and literacy data from 161 mothers in a poor, urban community in Venezuela. Results show that the academic literacy skills women learned in school and retained into adulthood, predict their health-related communication skills above and beyond the amount of schooling they received. The importance of female schooling in developing countries is discussed

GX 9+9: Variability of the X-Ray Orbital Modulation

Results of observations of the Galactic bulge X-ray source GX 9+9 by the All-Sky Monitor (ASM) and Proportional Counter Array (PCA) onboard the Rossi X-ray Timing Explorer are presented. The ASM results show that the 4.19 hour X-ray periodicity first reported by Hertz and Wood in 1987 was weak or not detected for most of the mission prior to late 2004, but then became strong and remained strong for approximately 2 years after which it weakened considerably. When the modulation at the 4.19 hour period is strong, it appears in folded light curves as an intensity dip over slightly less than 30% of a cycle and is distinctly nonsinusoidal. A number of PCA observations of GX 9+9 were performed before the appearance of strong modulation; two were performed in 2006 during the epoch of strong modulation. Data obtained from the earlier PCA observations yield at best limited evidence of the presence of phase-dependent intensity changes, while the data from the later observations confirm the presence of flux minima with depths and phases compatible with those apparent in folded ASM light curves. Light curves from a Chandra observation of GX 9+9 performed in the year 2000 prior to the start of strong modulation show the possible presence of shallow dips at the predicted times. Optical observations performed in 2006 while the X-ray modulation was strong do not show an increase in the degree of modulation at the 4.19 hour period. Implications of the changes in modulation strength in X-rays and other observational results are considered.Comment: 12 pages, 10 figures (1 color), in emulateapj forma

An Extended and More Sensitive Search for Periodicities in RXTE/ASM X-ray Light Curves

We present the results of a systematic search in approximately 14 years of Rossi X-ray Timing Explorer All-Sky Monitor data for evidence of periodicities not reported by Wen et al. (2006). Two variations of the commonly used Fourier analysis search method have been employed to achieve significant improvements in sensitivity. The use of these methods and the accumulation of additional data have resulted in the detection of the signatures of the orbital periods of eight low-mass X-ray binary systems and of ten high-mass X-ray binaries not listed in the tables of Wen et al.Comment: 20 pages, 22 figures, in emulateapj format; submitted to ApJ

Scattering and Iron Fluorescence Revealed During Absorption Dips in Circinus X-1

We show that dramatic spectral evolution associated with dips occurring near phase zero in RXTE observations of Cir X-1 is well-fit by variable and at times heavy absorption (N_H > 10^24 cm^-2) of a bright component, plus an underlying faint component which is not attenuated by the variable column and whose flux is ~10% of that of the unabsorbed bright component. A prominent Fe emission line at ~6.5 keV is evident during the dips. The absolute line flux outside the dips is similar to that during the dips, indicating that the line is associated with the faint component. These results are consistent with a model in which the bright component is radiation received directly from a compact source while the faint component may be attributed to scattered radiation. Our results are also generally consistent with those of Brandt et al., who found that a partial- covering model could explain ASCA spectra of a low-to-high transition in Cir X-1. The relative brightness of the two components in our model requires a column density of ~2*10^23 cm^-2 if the faint component is due to Thomson scattering in material that mostly surrounds the source. We find that illumination of such a scattering cloud by the observed direct component would produce an Fe K-alpha fluorescence flux that is in rough agreement with the flux of the observed emission line. We also conclude that if the scattering medium is not highly ionized, our line of sight to the compact source does not pass through it. Finally, we discuss simple pictures of the absorbers responsible for the dips themselves.Comment: Accepted for publication in The Astrophysical Journal (23 pages, including 11 figures