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961.
The heather moorland of the Scottish Highlands represents a highly symbolic habitat for the region. Significantly, recent work by ecologists and palaeobotanists has stressed the strong anthropogenic role in its development. Indeed, so vital is the role played by human interference, heather moorland is now seen as a cultural landscape. Yet despite being seen as a cultural landscape, there has hitherto been no attempt to use available documentary evidence to understand how this human interference may have affected its development over recent centuries. This paper examines such evidence, paying particular attention to how human activity contributed to its expansion over the early modern period and to its decline from ca. 1800 onwards, exploring such themes as moor burning, the harvesting of young tree growth, and grazing levels and practices, both before and after the clearances. Particular attention is paid to how the spread of sheep after the clearances contributed to the decline of heather moor and the role that heavy sheep grazing may have played in the deterioration in the quality of Highlands pastures during the mid-nineteenth century. 相似文献
962.
963.
964.
Robert K. Brigham 《The Historian; a journal of history》2009,71(3):627-628
965.
HIGHWAY INFRASTRUCTURE INVESTMENT AND COUNTY EMPLOYMENT GROWTH: A DYNAMIC PANEL REGRESSION ANALYSIS*
Piyapong Jiwattanakulpaisarn Robert B. Noland Daniel J. Graham John W. Polak 《Journal of regional science》2009,49(2):263-286
ABSTRACT This paper uses recent advances in dynamic panel econometrics to examine the impact of highway infrastructure on aggregate county‐level employment using data for all 100 North Carolina counties from 1985 through 1997. Results are compared to models that do not take endogeneity of highway investment and dynamics of employment adjustment into account. Fully specified dynamic models are found to give insignificant results compared to these other models. Thus, when these issues are properly modeled, the results show that improvements in highways have no discernible impact on employment. 相似文献
966.
967.
968.
Robert G. Wallace 《对极》2009,41(5):916-951
Abstract: The geographic extent, xenospecificity, and clinical course of influenza A (H5N1), the bird flu strain, suggest the virus is an excellent candidate for a pandemic infection. Much attention has been paid to the virus's virology, pathogenesis and spread. In contrast, little effort has been aimed at identifying influenza's social origins. In this article, I review H5N1's phylogeographic properties, including mechanisms for its evolving virulence. The novel contribution here is the attempt to integrate these with the political economies of agribusiness and global finance. Particular effort is made to explain why H5N1 emerged in southern China in 1997. It appears the region's reservoir of near-human-specific recombinants was subjected to a phase change in opportunity structure brought about by China's newly liberalized economy. Influenza, 200 nm long, seems able to integrate selection pressures imposed by human production across continental distances, an integration any analysis of the virus should assimilate in turn. 相似文献
969.
970.
Mietje Germonpré Mikhail V. Sablin Rhiannon E. Stevens Robert E.M. Hedges Michael Hofreiter Mathias Stiller Viviane R. Després 《Journal of archaeological science》2009
Using multivariate techniques, several skulls of fossil large canids from sites in Belgium, Ukraine and Russia were examined to look for possible evidence of the presence of Palaeolithic dogs. Reference groups constituted of prehistoric dogs, and recent wolves and dogs. The fossil large canid from Goyet (Belgium), dated at c. 31,700 BP is clearly different from the recent wolves, resembling most closely the prehistoric dogs. Thus it is identified as a Palaeolithic dog, suggesting that dog domestication had already started during the Aurignacian. The Epigravettian Mezin 5490 (Ukraine) and Mezhirich (Ukraine) skulls are also identified as being Palaeolithic dogs. Selected Belgian specimens were analyzed for mtDNA and stable isotopes. All fossil samples yielded unique DNA sequences, indicating that the ancient Belgian large canids carried a substantial amount of genetic diversity. Furthermore, there is little evidence for phylogeographic structure in the Pleistocene large canids, as they do not form a homogenous genetic group. Although considerable variation occurs in the fossil canid isotope signatures between sites, the Belgian fossil large canids preyed in general on horse and large bovids. 相似文献