Migration and market wage risk

The author presents an approach to the analysis of labor migration that incorporates the role of market wage variability as a source of information in individual migration decisions. "The focus...is on quantifying the effects of the origin market acting through amenities and the share of market-specific wage variability as it affects forecasts of alternative wages and forecast precision. A subsample of employed males...from the [U.S.] National Longitudinal Survey of Youth (NLS) age 16 to 22 years is used for estimation. The empirical results are consistent with the theoretically predicted relationship between migration propensities and regional differences in the information content of wages. In addition, the results provide evidence that risk aversion deters migration given uncertainty, measured by forecast precision, about alternative market wage levels."     

THE BEGINNINGS OF ISLAMIC STONEPASTE TECHNOLOGY*

A multidisciplinary programme of research on Islamic pottery has been focused on questions of the dating, provenance and technology of Islamic pottery. One particular question has been the development of stonepaste, a material made primarily of crushed quartz with added frit-glass and clay. The combination of the different approaches of this study has revealed early foundations for the technology in ninth-century AD Iraq, apparently originating in the clay ceramic rather than the ‘Egyptian faience’ tradition. Subsequent and final practice developed in tenth- and eleventh-century AD Egypt. This technology becomes the primary body for all fine Islamic ceramics.     

Weighted Spatial Adaptive Filtering: Monte Carlo Studies and Application to Illicit Drug Market Modeling

This paper introduces a pattern recognizer, similar to weighting schemes used in combining time series forecasts, for use in spatial adaptive filtering applied to estimating multivariate cross-sectional models. The pattern recognizer enhances the ability to automatically detect and estimate parameters with discontinuous or sharp gradient changes over geographic contexts. Results from Monte Carlo studies suggest that the weighted spatial adaptive filter is at least as accurate as the unweighted filter for cases having smoothly changing parameters, but superior for cases having discontinuous, step-jump parameters. A case study on illicit drug-market activities using census tract-level data from Pittsburgh, Pennsylvania, further illustrates the advantages of the weighted filter.     

CHEMICAL ANALYSIS OF COPPER ALLOY TRADE METAL FROM A POST-CONTACT HURON SITE IN ONTARIO,CANADA

Fifty-three copper-based metal fragments, recovered from the Robitaille site in southcentral Ontario, were analysed by neutron activation to establish their chemical make-up and to sort them by their trace elemental chemistries. Three different European copper samples, one brassy copper and 48 brass samples with five different chemistries were found. As few as eight trading actions may account for all of the recovered European metal fragments.     

THE POSSIBLE FRACTIONATION OF LEAD ISOTOPES IN ANCIENT METALLURGICAL PROCESSES

The possibility of lead isotope fractionation in ancient lead production is examined. Kinetic theory relating to isotopic fractionation in non-equilibrium evaporation is considered and the feasibility of the alteration of lead isotope abundance ratios in ore roasting and smelting is assessed. Previous experimental work is shown to have been inconclusive and conclusions are drawn on the need for further research to quantify the possible extent of fractionation in practice.     

RADIOCARBON DATES FOR BEESWAX FIGURES IN THE PREHISTORIC ROCK ART OF NORTHERN AUSTRALIA

Accelerator mass spectrometry radiocarbon ages have been taken for a test suite of small samples of material removed from some of the ‘beeswax’art figures found in rock shelters in northern Australia. The results indicate that we can reliably date this unique form of rock art with no noticeable damage. We had not expected to find figures of any great antiquity, and so we were surprised to find that the ages obtained spanned the time period from the recent past to about 4000 BP.