The U.S. demographic transition

agriculture;manufacturing;technological change

New oxygen isotope evidence for the origin of mesosiderites and main group pallasites

High precision oxygen isotope analyses reveal that the silicate portion of mesosiderites are indistinguishable from the HEDs and suggest a common origin. However, the main group pallasites have a distinct signature, and therefore different source

Measuring the welfare gain from personal computers: a macroeconomic approach

The welfare gain to consumers from the introduction of personal computers is estimated here. A simple model of consumer demand is formulated that uses a slightly modified version of standard preferences. The modification permits marginal utility, and hence total utility, to be finite when the consumption of computers is zero, implying that the good won't be consumed at a high enough price. It also bounds the consumer surplus derived from the product. The model is calibrated and estimated using standard national income and product account data. The welfare gain from the introduction of personal computers is in the range of 2 percent to 3 percent of consumption expenditure.

Measuring the Welfare Gain from Personal Computers: A Macroeconomic Approach

The welfare gain to consumers from the introduction of personal computers is estimated here. A simple model of consumer demand is formulated that uses a slightly modified version of standard preferences. The modification permits marginal utility, and hence total utility, to be finite when the consumption of computers is zero. This implies that the good won't be consumed at a high enough price. It also bounds the consumer surplus derived from the product. The model is calibrated/estimated using standard national income and product account data. The welfare gain from the introduction of personal computers is in the range of 2 to 3 percent of consumption expenditure.Compensating Variation, Computers, Electricity, Equivalent Variation, Technological Progress, Tornqvist Price Index, Welfare Gain.

IRDS prototyping with applications to the representation of EA/RA models

The requirements and system overview for the Information Resources Dictionary System (IRDS) are described. A formal design specification for a scaled down IRDS implementation compatible with the proposed FIPS IRDS standard is contained. The major design objectives for this IRDS will include a menu driven user interface, implementation of basic IRDS operations, and PC compatibility. The IRDS was implemented using Smalltalk/5 object oriented programming system and an ATT 6300 personal computer running under MS-DOS 3.1. The difficulties encountered in using Smalltalk are discussed

Guinea worm infection in northern Nigeria: Reflections on a disease approaching eradication.

: Global eradication of the guinea worm (Dracunculus medinensis) is near, although perhaps delayed a little by the discovery of a transmission cycle in dogs. It is therefore an appropriate time to reflect on the severe impact of this infection on the life of the communities where it was endemic prior to the start of the global eradication programme in 1981. From 1971 to 1974, we conducted a series of unpublished studies on guinea worm in a group of villages in Katsina State, northern Nigeria, where the infection was highly endemic. These studies demonstrated the high rate of infection in affected communities, the frequent recurrence of the infection in some subjects and the long-standing disability that remained in some infected individuals. Immunological studies showed a high level of immediate hypersensitivity to adult worm and larval antigens but a downregulation of Th1-type T-cell responses to worm antigens. Freeing communities such as those described in this article from the scourge of guinea worm infection for good will be an important public health triumph.<br/