Enhancing the Quality of Data on Income: Recent Developments in Survey Methodology

In this paper, we evaluate two survey innovations aimed at improving income measurement. These innovations are (1) integrating the question sequences for income and wealth which may elicit more accurate estimates of income from capital than has been true in the past, and (2) changes in the periodicity over which income flows are measured, which may provide a closer match between what the survey respondent knows best and the periodicity contained in survey measurement. These innovations have been introduced into both the Health and Retirement Study (HRS) and the study of Asset and Health Dynamics Among the Oldest Old (AHEAD). Based on the results reported in this paper, the potential return in quality of income measurement from these innovations is substantial.

Decay estimates for variable coefficient wave equations in exterior domains

In this article we consider variable coefficient, time dependent wave equations in exterior domains. We prove localized energy estimates if the domain is star-shaped and global in time Strichartz estimates if the domain is strictly convex.Comment: 15 pages. In the new version, some typos are fixed and a minor correction was made to the proof of Lemma 1

Bilharziasis in the African Infant and Child in the Mtoko District, Southern Rhodesia

A CAJM study on Bilharziasis in the African Infant in Southern Rhodesia during the 1950's.This study was undertaken with several objects in view.. First of all we wanted to know how frequently bilharziasis is likely to infest infants up to the age of two years in an endemic area. On first thoughts it would seem reasonable for the disease to be rarely encountered at this stage of life, since the African babe is seldom exposed directly to the streams or the water’s edge for fear that it might be drowned or injured by crocodiles. On the other hand, it must be admitted that the infant is often washed in water carried from the river in buckets or gourds, and unless the water is kept standing for 24 hours or boiled soon after collection, many of these children can be expected to acquire the disease. Then there is the possibility that the African infant born of a mother, herself probably infected for many years, may have a passive immunity conferred on it by her and is therefore more able to resist infection by the cercariae at this age than when it is older

A disrupted circumstellar torus inside eta Carinae's Homunculus Nebula

We present thermal infrared images of the bipolar nebula surrounding eta Carinae at six wavelengths from 4.8 to 24.5 microns. These were obtained with the MIRAC3 camera system at the Magellan Observatory. Our images reveal new intricate structure in the bright core of the nebula, allowing us to re-evaluate interpretations of morphology seen in images with lower resolution. Complex structures in the core might not arise from a pair of overlapping rings or a cool (110 K) and very massive dust torus, as has been suggested recently. Instead, it seems more likely that the arcs and compact knots comprise a warm (350 K) disrupted torus at the intersection of the larger polar lobes. Some of the arcs appear to break out of the inner core region, and may be associated with equatorial features seen in optical images. The torus could have been disrupted by a post-eruption stellar wind, or by ejecta from the Great Eruption itself if the torus existed before that event. Kinematic data are required to rule out either possibility.Comment: 8 pages, 3 figures (Fig. 1 in color); to appear in ApJ Letter