首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   23篇
  免费   1篇
  2018年   2篇
  2016年   1篇
  2014年   3篇
  2013年   7篇
  2012年   1篇
  2011年   2篇
  2010年   4篇
  2008年   2篇
  2007年   1篇
  2002年   1篇
排序方式: 共有24条查询结果,搜索用时 15 毫秒
1.
2.
Clovis, Nenana, and Denali are the earliest well-documented archaeological complexes in the New World. Clovis has been found at sites throughout the lower 48 states of the USA and in parts of Canada but not in Alaska, whereas Nenana and Denali have been found in Alaska but not elsewhere in North America. In 1991, Goebel and colleagues reported phenetic analyses of tool types from Clovis, Nenana, and Denali. They found that Nenana clustered more closely with Clovis than with Denali, and concluded from this that Nenana was likely ancestral to Clovis. Goebel et al.'s study has been cited frequently since it was published, and their conclusions have been widely accepted. Here we explain why analyses of the type performed by Goebel et al. are problematic and also demonstrate empirically that their results are dependent on the algorithm and distance measure used. We then reanalyze their dataset with a technique from biology called cladistics. Cladistics has replaced phenetics as the method of choice for reconstructing evolutionary relationships in biology, because it is more objective. The results of this analysis differ from those obtained by Goebel and colleagues. The results strongly suggest that Denali and Clovis are in fact more closely related to each other than either is to Nenana.  相似文献   
3.
This article considers how nonhuman animals are enrolled in the construction of gendered identities. Specifically, I interrogate two gendered figures with which I was repeatedly confronted over the course of researching cougar–human relationships on Vancouver Island, home to what is estimated to be North America's densest population of cougars. The first figure, Cougar Annie, was a woman ‘settler’ on western Vancouver Island, reputed to have killed over 100 cougars in her lifetime and now celebrated as a strong, independent female. The second figure is a contemporary trope, an older woman who expresses interest in younger men, known in slang speech as a ‘cougar’. Both figures are intimately bound to a third figure, the animal cougar, Puma concolor, whose material–semiotic relationship to humans both performs and is performed by ‘cougars’ and Cougar Annie. Haraway's conception of figures as embodied and performative mappings of power is central to this article's discussion, which lies at the intersection of animal studies, more-than-human geographies, posthumanism, and feminist science studies. Methodologically, I draw on interviews and archival research to trace the historical and contemporary specificities of these two figures – Cougar Annie and ‘cougars’ – revealing how they are informed by, and simultaneously produce, uphold, and perform, gendered understandings of the relationship between humans and cougars, predator and prey, humans and animals, and culture and nature.  相似文献   
4.
5.
Archaeologists disagree about how farming began in Britain. Some argue it was a result of indigenous groups adopting domesticates and cultigens via trade and exchange. Others contend it was the consequence of a migration of farmers from mainland Europe. To shed light on this debate, we used radiocarbon dates to estimate changes in population density between 8000 and 4000 cal BP. We found evidence for a marked and rapid increase in population density coincident with the appearance of cultigens around 6000 cal BP. We also found evidence that this increase occurred first in southern England and shortly afterwards in central Scotland. These findings are best explained by groups of farmers from the Continent independently colonizing England and Scotland, and therefore strongly support the migrant farmers hypothesis.  相似文献   
6.
7.
Despite the importance of the Clovis–Folsom transition for understanding the history of western North America, its spatiotemporal dynamics remains unclear. Here we report a three-part study in which we investigated the transition using radiocarbon dates from Clovis and Folsom sites. In the first part of the study, we used dates from Folsom site-phases to determine when and where Folsom originated. In the second part of the study, we employed Clovis and Folsom dates in analyses designed to determine whether Folsom spread via demic diffusion or cultural diffusion. In the third part of the study we investigated the velocity of the Clovis–Folsom transition. The analyses suggest that Folsom first appeared around 12,800 calBP in the northern High Plains and spread north and south from there. They also suggest that the spread of Folsom was, at least in part, the result of population expansion. In addition, the analyses indicate that the spread of Folsom was relatively fast for a prehistoric diffusion but well below the maximum velocity that has been estimated for such events. These findings, in turn, have implications for the hypotheses that have been put forward to explain the Clovis–Folsom transition. They refute the idea that the Clovis–Folsom transition resulted from an extraterrestrial impact over northern North America at 12,900 ± 100 calBP but are consistent with the alternative proposal that the transition was a response to climate-driven environmental change.  相似文献   
8.
9.
We show that Steele’s (2010) criticisms of Hamilton and Buchanan (2007) and Buchanan et al. (2008) do not hold water and demonstrate that his re-analyses of Hamilton and Buchanan’s (2007) and Buchanan et al'.s (2008) datasets are flawed. In the process, we highlight some important issues for researchers interested in using radiocarbon dates to reconstruct population movements and demography. Most notably, we explain why OLS regression is preferable to RMA regression when estimating diffusion velocity, and demonstrate that the summed probability distributions yielded by CalPal are more reliable as guides to past demographic change than those produced by Calib and OxCal.  相似文献   
10.
The initial colonization of North America remains a controversial topic. There is widespread agreement that Clovis and related cultures of the Early Paleoindian period (∼11,500–10,500 BP) represent the first well-documented indications of human occupation, but considerable differences of opinion exist regarding the origins of these cultures. Here, we report the results of a study in which data from a continent-wide sample of Early Paleoindian projectile points were analyzed with cladistic methods in order to assess competing models of colonization as well as several alternative explanations for the variation among the points, including adaptation to local environmental circumstances, cultural diffusion, and site type effects. The analyses suggest that a rapidly migrating population produced the Early Paleoindian projectile point assemblages. They also suggest that the population in question is unlikely to have entered North America from either the Isthmus of Panama or the Midatlantic region. According to the analyses, the Early Paleoindians are more likely to have entered North America via either the ice-free corridor between the Laurentide and Cordilleran ice sheets that is hypothesized to have opened around 12,000 BP, or the Northwest Coast.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号