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21.
Taxonomic, anatomical, and spatio-temporal variations in the stable carbon and nitrogen isotopic compositions of plants from an African savanna 总被引:5,自引:1,他引:4
Jacqui Codron Daryl Codron Julia A. Lee-Thorp Matt Sponheimer William J. Bond Darryl de Ruiter Rina Grant 《Journal of archaeological science》2005,32(12):1757-1772
Stable carbon (δ13C) and nitrogen (δ15N) isotope ratios are commonly used to reconstruct palaeodiets and palaeoenvironments. The method is based on our knowledge of isotopic patterns in plants, which are subject to taxonomic and environmental variability. While previous researchers have addressed isotopic variability amongst plants, no studies have looked extensively at a broad suite of taxa over multiple temporal scales from within the savanna biome so as to provide baseline data for palaeodietary and palaeoenvironmental studies. Here we document variations in the isotopic compositions of plants collected over two years from the Kruger National Park, South Africa, with respect to species and anatomical differences, and the influences of geological substrate and spatio-temporal shifts in climate. Results show that environmentally-induced carbon isotopic variations in plants within this region are generally smaller than 2‰, which is lower than what has been previously reported for plants compared across multiple habitat-types. These data suggest that δ13C differences of 2‰ or more (or 1‰ if the diet is predominantly C4) between animals from a given area reliably indicate real dietary differences. Plant δ15N values vary greatly between different microhabitats (by up to 4‰), responding to a range of environmental influences that may, in turn, significantly influence variation in animal δ15N values. 相似文献
22.
Risk perceptions are important to the policy process because they inform individuals’ preferences for government management of hazards that affect personal safety, public health, or ecological conditions. Studies of risk in the policy process have often focused on explicating the determinants of risk perceptions for highly salient, high consequence hazards (e.g., nuclear energy). We argue that it is useful to also study more routinely experienced hazards; doing so shows the relevance of risk perceptions in individuals’ daily lives. Our investigation focuses on the impact perceived risk has on citizens’ preferences over hazard management policies (as distinct from identifying risk perception determinants per se). We use a recursive structural equation model to analyze public opinion data measuring attitudes in three distinct issue domains: air pollution, crime, and hazardous waste storage and disposal. We find that citizens utilize perceived risk rationally: greater perceived risk generally produces support for more proactive government to manage potential hazards. This perceived risk–policy response relationship generally holds even though the policy options respondents were asked to consider entailed nontrivial costs to the public. The exception seems to be when individuals know less about the substantive issue domain. 相似文献
23.
Will J. Grant Brenda Moon Janie Busby Grant 《Australian journal of political science》2010,45(4):579-604
The recent emergence of online social media has had a significant effect on the contemporary political landscape, yet our understanding of this remains less than complete. This article adds to current understanding of the online engagement between politicians and the public by presenting the first quantitative analysis of the utilisation of the social network tool Twitter by Australian politicians. The analysis suggests that politicians are attempting to use Twitter for political engagement, though some are more successful in this than others. Politicians are noisier than Australians in general on Twitter, though this is due more to broadcasting than conversing. Those who use Twitter to converse appear to gain more political benefit from the platform than others. Though politicians cluster by party, a relatively ‘small world’ network is evident in the Australian political discussion on Twitter. 相似文献
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By Emma Pomeroy Jennifer Grant Devin Ward Sam Benady Ma Cristina Reinoso del Río José Ma Gutierrez López 《Post-Medieval Archaeology》2013,47(2):239-255
SUMMARY: In 2014, during construction work at the ex-Civil Hospital in Gibraltar, excavations led by the Gibraltar Museum revealed a major, previously unknown burial ground containing more than 200 skeletons. We present the historical, archaeological and radiometric dating evidence from the site alongside the results of initial osteological analyses. The data indicate that the burials pertain to an earlier 16th-century Spanish hospice, and therefore stand to offer new insights into the functioning of this early modern hospital and the health and movements of people at a time of incipient globalization. 相似文献
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Attempts to transform political agendas are closely associated with the role of the media in shaping perceptions, reflecting programs of political organisations, influencing institutional practices and applying pressure on divergent interests. By examining the role of an influential news magazine in voicing concerns about welfare and environment policies over a 40-year period, this article tests arguments about the salience of 'old' and 'new' politics issues as well as the changing character of debates about these questions in efforts to create a sustainable, competitive and global economy. Apart from examining the capacity of the media to change their storylines (or ways of thinking about an issue), the article considers how they attempt to draw on credible news sources to substantiate their reports. 相似文献