George L. W. Perry

Learn More
THE CONCEPT of a natural unemployment rate has been central to most modern models of inflation and stabilization. According to these models, inflation will accelerate or decelerate depending on whether unemployment is below or above the natural rate, while any existing rate of inflation will continue if unemployment is at the natural rate. The natural rate(More)
OVER THIRTY YEARS ago, in his presidential address to the American Economic Association, Milton Friedman asserted that in the long run the Phillips curve was vertical at a natural rate of unemployment that could be identified by the behavior of inflation. Unemployment below the natural rate would generate accelerating inflation, and unemployment above it,(More)
Wildfires statistics for the conterminous United States (U.S.) are examined in a spatially and temporally explicit manner. We use a high-resolution data set consisting of 88,916 U.S. Department of Agriculture Forest Service wildfires over the time period 1970-2000 and consider wildfire occurrence as a function of ecoregion (land units classified by climate,(More)
Remote sensing, when used in conjunction with landscape pattern metrics, is a powerful method for the study of ecological dynamics at the landscape scale by means of multi-temporal analysis. In this paper, we examine temporal change in open formations in the natural reserve of Poggio all’Olmo (central Italy). This area has undergone rural depopulation and(More)
We describe a range of methods for the description and analysis of spatial point patterns in plant ecology. The conceptual basis of the methods is presented, and specific tests are compared, with the goal of providing guidelines concerning their appropriate selection and use. Simulated and real data sets are used to explore the ability of these methods to(More)
Many different sciences have developed many different tests to describe and characterise spatial point data. For example, all the trees in a given area may be mapped such that their x, y co-ordinates and other variables, or ‘marks’, (e.g. species, size) might be recorded. Statistical techniques can be used to explore interactions between events at different(More)
In many areas of the northern Mediterranean Basin the abundance of forest and scrubland vegetation is increasing, commensurate with decreases in agricultural land use(s). Much of the land use/cover change (LUCC) in this region is associated with the marginalization of traditional agricultural practices due to ongoing socioeconomic shifts and subsequent(More)
At the time of Māori settlement, ca. 750 years ago, New Zealand’s ecosystems experienced catastrophic change, including the introduction of fire to ignition-limited ecosystems and the resulting widespread loss of forest. While high-resolution sediment-charcoal analyses suggest this forest loss was rapid, Māori populations were small and transient during the(More)