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The ESR dating method requires to describe the evolution of the ESR signal intensities vs. increasing gamma doses, then to extrapolate the equivalent dose of radiation received by the sample since its deposition using mathematical fitting. The function classically used to describe the growth curves of ESR aluminium signal in quartz was recently discussed and challenged for Lower Pleistocene sediments. In the present work, some alluvial sediments sampled in Upper Pleistocene fluvial terraces of the Yellow River system (China) permit us to test the application of another extrapolation function (linear + exponential) recently proposed for Lower Pleistocene sediments. The equivalent doses obtained here for the recent deposits of the Yellow River system and the corresponding ages are promising and indicate the potential of ESR to date quartz deposits from Upper Pleistocene times.  相似文献   
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This research extends theorizing about the implications of political environments to the content of policy areas. We consider the case of Arctic policy in Canada and the United States as an example of what we label as component-driven policymaking. We show how the lack of a clear constituency and the lack of a stable policy subsystem for the Arctic create a policy environment for which the politics of particular issues dominate Arctic policymaking. The result is a policy space labeled Arctic policy that lacks policy coherence. We suggest that similar features of component-based policymaking help explain limited policy coherence for a variety of policy areas such as policies for children, families, rural areas, urban areas, and women in the United States.  相似文献   
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Book reviewed in this article:
Dipesh Chakrabarty, Provincializing Europe: Postcolonial Thought and Historical Difference  相似文献   
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Seismic uplift of the harbour of ancient Aigeira, Central Greece   总被引:2,自引:0,他引:2  
The Mavra Litharia cove, between Akrata and Derveni, in the North Peloponnesian coast (Central Greece), has been identified as the site of the harbour of the Hellenistic Aigeira, one of the very few natural harbours along the uplifting, fault-controlled North Peloponnesian coast.
Geomorphological, marine biological and archaeological data as well as radiocarbon dating of marine fossils testify to a 2m relative land uplift since Hellenistic times (around 2000 years bp), part of which (1 m at least) was probably seismic, dated to the Byzantine period (AD 900–1200). This palaeoseismic event, as well as others deduced from archaeological data, are not included in the historical seismology records, but had probably dramatic impacts on the economic and cultural history of ancient Aigeira.
The amplitude of uplift at Mavra Litharia is of the same order of magnitude as submersion dominating the Aegean and, with the exception of the arc, the higher Holocene uplift rate recorded in this area and the surrounding regions. This result is consistent with the Quaternary uplift history of North Peloponnesus.  相似文献   
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Today, exactly 500 years after the discovery of America, there is still a lot of controversy about the history of syphilis in Europe, especially about the Columbian and pre-Columbian hypotheses. This paper presents evidence for the presence of venereal treponematosis in the late Antiquity in France. The case that we examined comes from the necropolis of Costebelle (3rd-5th centuries AD; Hyères, Var, France). Grave no. 1 contained the well-preserved skeleton of a relatively old woman with the skeletal remains of an approximately 7-month-old fetus in her pelvic cavity. The osseous lesions of the fetal remains can be described in four groups: periosteal appositions on the skull vault (frontal and parietal); signs of periostitis on the long bones (bilateral cortical irregularities, predominantly on the left side, which affect first of all tibiae, femora, fibulae, radii and humeri, particularly in the metaphyseal region); some infraperiosteal detachment reminiscent of an infraperiosteal haematoma surrounding the distal extremity of the left forearm and the left hand; and finally, the irregular lesions of the humeral distal and proximal tibial metaphyses reminded us radiologically of Wimberger's signs. The most probable diagnosis of all the lesions mentioned above is that of a precocious congenital syphilis. This case consists of an argument against the epidemiological theories about the migration of Treponema pallidum from the New World back to the Old World starting at the end of the 15th century.  相似文献   
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