It is well known that some XML elements correspond to objects (in the sense of object-orientation) and others do not. The question we consider in this paper is what benefits we can derive from paying attention to such object semantics, particularly for the problem of keyword queries. Keyword queries against XML data have been studied extensively in recent years, with several lowest-common-ances...

We analyze the relative growth performance of open economies in a two-country model where di¤erent endowments of labor and a natural resource generate asymmetric trade. A resource-rich economy trades resource-based intermediates for …nal manufacturing goods produced by a resource-poor economy. Productivity growth in both countries is driven by endogenous innovations. The e¤ects of a sudden incr...

Rangelands of China have for centuries provided forage for livestock but now their role in water, soil, and biodiversity conservation is being recognised by Governments and people. However, much of the rangelands has recently degraded anddesertification is nowawidespread problem.The cause of the degradation is over-grazing andover-cultivation. Climate change is exacerbating theproblem.TheChines...

This paper develops a one-sector endogenous growth model in which renewable natural resources are postulated as both a factor of production and as a measure of environmental quality. We show that sustained economic growth and a non-deteriorating environment can coexist along the economy’s balanced growth path. Moreover, the output growth rate is positively related to the steady-state level of n...

There are two main challenges in managing natural resources. One is to respond appropriately to the ecological characteristics of a given environment, preserving its integrity and functions while assuring a flow of benefits from it. This challenge is mostly about content— the what and when of managing natural resources. The other is to respond to the social characteristics of the same environme...

Population-environment studies have implicitly permeated demography but only until the mid-20 century has the debate been rekindled and research expanded. This article reviews the origins and history of the population-environment debate and attempts to provide insight into the most recent approaches and methodology. Beginning with the most traditional relationships established between demograph...