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61.
A data-determined method is proposed to test for the law of one price as a long-run equilibrium condition and to identify which markets in a network of spatially dispersed commodity markets quote the reference price. The method consists of supplementing Johansen's FIML cointegration procedure with a permanent-transitory decomposition and rules of inference in linear time-series models with unit roots. As an example, we apply our method to prices of six corn markets in Benin. We find that the law of one price holds in the long-run. It appears that two rural markets quote the reference price: their prices adjust fastest towards the permanent change induced by the common stochastic trend.  相似文献   
62.
Although the aetiology of bone pathologies in cattle is poorly documented, various deformations in the skeleton have been attributed to draught exploitation in the archaeozoological literature. This paper summarizes the results of an osteological study that was undertaken on the feet of modern draught oxen. This led to the definition of a series of draught‐related anomalies. In an attempt to describe the pathologies in a more consistent and quantitative way, a scoring scale for each individual bone pathology was established. The developed method is applied to cattle remains from four Roman and one late medieval site. The distribution of the observed pathological indices (PIs) on the first phalanges is interpreted in terms of the age structure of the cattle populations, and the possible modes of cattle exploitation and meat consumption in various settlement types. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   
63.
Previous geographical research with street children has principally focused on their micro-geographies in the city. This paper draws on nomadic and episodic processes of homeless mobility, to explore street children's geographies from a wider social, spatial and temporal perspective. By examining street life in Kampala, Uganda as a continued negotiation of public/private and street/non-street locations, the fluid nature of street children's identity is illustrated. Over time, movement between spaces, such as divergent city niches, institutions, homes and other towns, is often subject to power relations operating in street/non-street spaces with each requiring conformity to a different set of values and behaviours. The paper demonstrates how this results in children's street identity changing as they move through the street life path.  相似文献   
64.
Overpressure in ‘old’ sedimentary basins that have not undergone rapid, recent sedimentation cannot be easily explained using traditional burial‐driven mechanisms. The last significant burial event in the Cooper Basin, Australia, was the Late Cretaceous deposition of the Winton Formation (98.5–90 Ma). Maximum temperature in the basin was attained during the Late Cretaceous, with cooling beginning prior to 75 Ma. Hence, overpressure related to rapid burial or palaeomaximum temperatures (e.g. hydrocarbon generation) must have developed prior to 75 Ma. Retaining overpressure for 75 Ma in ‘old’ basins such as the Cooper Basin requires extremely low seal permeabilities. An alternative explanation is that overpressure in the Cooper Basin has been generated because of an increase in mean stress associated with an increase in horizontal compressive stress since Late Cretaceous times. Structural observations and contemporary stress data indicate that there has been an increase in mean stress of approximately 50 MPa between Late Cretaceous times to that presently measured at 3780 m. The largest measured overpressure in the Cooper Basin is 14.5 MPa at 3780 m in the Kirby 1 well. Hence, disequilibrium compaction driven by increasing mean stress can explain the magnitude of the observed overpressure in the Cooper Basin. Increases in mean stress (tectonic loading) may be a feasible mechanism for overpressure generation in other ‘old’ basins that have undergone a recent increase in horizontal stress (e.g. Anadarko Basin).  相似文献   
65.
Easter Island, or Rapa Nui, has been the focus of much research and speculation, particularly with reference to the island’s hundreds of giant, enigmatic statues and the set of conditions that supported their construction and transportation. In this paper, we analyze an abundant class of lithic artifacts, mata’a, to study of patterns of cultural transmission with implications for the evolution of groups, competition, and scale of socio-political organization among this island population. While these kinds of studies often draw upon assemblages of decorated ceramics, here we show how analysis of variability unconstrained by performance allows us to measure aspects of inheritance related to the manufacture of these artifacts. In the case of mata’a from Rapa Nui, we demonstrate that it is possible to reach falsifiable conclusions about the evolutionary dynamics that shaped the remarkable archaeological record on Rapa Nui.  相似文献   
66.
The aim of the paper is to summarise the present state of knowledge concerning bitumen trade in the Near East from the Palaeolithic (70,000 BP) to the Early Islamic period. During the Palaeolithic and Early Neolithic period, bitumen utilisation was mostly concentrated in settlements close to oil seeps. From the Ubaid 3 period, bitumen from the Mosul area became more important and was traded as far as the southern Persian Gulf. The Uruk period is a turning point for Mesopotamian history as settlements evolved into city‐states. These cities had a great need for raw materials, and this marks the beginning of large‐scale exploitation of Hit bitumen. This bitumen was traded at settlements along the Euphrates, where a large trade network was established. Hit bitumen entered the Persian Gulf at the turn of the second millennium (Dilmun period). Bitumen from Iraq (Mosul and Hit) became predominantly used in most settlements along the southern coast of the Gulf. During this period Iranian bitumen was also exported and this supply tended to increase, especially during the Partho‐Sasanian period. Dead Sea bitumen had its own exchange network, which was concentrated across present‐day Israel and Egypt where it was extensively used for mummification.  相似文献   
67.
在漫长的人类史中,铁器时代占有重要的地位,而早期铁器时代的炼铁技术则更值得研究和探索。本文是麻省理工学院的S.特里·乔尔兹写于上世纪80年代的一篇实验性研究文章。其中阐述了对于东非坦桑尼亚卡盖拉地区早期铁器时代炼铁所选用黏土的实验过程以及研究结果。作者长期在卡盖拉地区进行考察,并通过田野采集、实验分析和测试焙烧的方法对该地区早期铁器时代炼铁熔炉的材质选择进行了研究。结果表明,卡盖拉地区的史前炼铁工人对于建炉材质有着自己的认识,他们会选择耐火性较高的黏土来建造可能会承受极高温度的部分,如焙烧中心、风口末端,并且已经掌握了通过向黏土添加瘠性掺合料,从而提高黏土的耐火性并防止其在极端高温中膨胀、破裂、剥落。同时,他们在材料黏土的耐火性、稳定性和可获得性方面进行了权衡。他们并不完全依赖从远处沼泽地区采集的高品质黏土,而是更多地选择居住环境周围容易获得的沙质黏土和白蚁冢。通过向其中添加掺合料,这些材料同样在建炉过程中取得了良好的效果。本文的研究揭示出非洲早期铁器时代的炼铁工人对材料黏土的选择方式和依据,说明了他们非常重视综合考量,权衡技术控制、劳动效率和材料可获得性等诸方面因素,从而对于制铁资源做出了合理的折衷选择。  相似文献   
68.
The concept of Payments for Ecosystem Services (PES) is gaining increasing attention among scholars as well as conservation and development practitioners. The premises of this innovative conservation approach are appealing: private land users, usually poorly motivated to protect nature on their land, will do so if they receive payments from environmental service buyers which cover part of the land users’ opportunity costs of developing the land. However, this article warns against an over‐enthusiastic adoption of a one‐sided market‐based PES approach. Based on a field study of the Regional Integrated Silvopastoral Approaches to Ecosystem Management Project (RISEMP), one of the main PES pilot projects in Nicaragua, it suggests that a mixture of economic and non‐economic factors motivated farmers to adopt the envisaged silvopastoral practices and that the actual role of PES is mistakenly understood as a simple matter of financial incentives. The authors argue that PES approaches should be understood as a part of a broader process of local institutional transformation rather than as a market‐based alternative for allegedly ineffective government and/or community governance.  相似文献   
69.
Examination of the histological structure of bone not only helps investigators to estimate age at death but can also aid in the diagnosis of palaeopathological lesions. The purpose of this paper is to assess whether histological features as described in the literature can confirm the macroscopic diagnoses of ossified subperiosteal haematomas associated with healed scurvy and syphilitic bone changes observed on the anterior tibiae of individuals from a 19th century mining community from Kimberley South Africa. The frequent occurrence of these two diseases amongst the deceased was well established in related hospital documents and governmental documents. A section of bone was removed from lesions on the tibiae of 14 individuals. These bone changes were macroscopically diagnosed as being indicative of either treponematosis ossified subperiosteal haematomas or non‐specific periostitis. Cross‐sections were prepared for microscopic investigation using a manual ground section technique. Ossified haematomas were histologically identified in seven individuals. These sections were characterised by normal cortical bone an intact original periosteal surface and newly formed radiating trabecular bone apposing it. Three phases of ossified subperiosteal haematoma formation and remodelling could be distinguished. Infectious bone changes most likely associated with treponematosis were observed in one individual. These were characterised by lysis and numerous resorption holes/channels. No clear distinction could be made between the internal spongy cortical or newly formed bone. Histological features described by some authors as characteristic of this condition could not be identified. In addition three individuals presented with microscopic features indicative of both the aforementioned bone affections and three did not show any pathological changes on microscopic level. It was concluded that although specific pathological conditions can most likely not be diagnosed purely on the basis of histomorphological observations broad distinctions could be made between lesions caused by the ossification of subperiosteal haematomas and bone changes due to infectious diseases. Copyright © 2009 John Wiley & Sons Ltd.  相似文献   
70.
Two concentrations of animal bones, almost exclusively from small mammals and wild birds, were found within the destruction debris of a Roman bath complex in Sagalassos (SW Turkey). The overall species spectrum, skeletal element representation, fragmentation and preservation condition of the bones indicate that they represent the prey remains of a large nocturnal avian predator, more precisely the eagle owl (Bubo bubo). Differences in skeletal element representation and in prey species' spectrum show that the two bone clusters derive from pellets deposited near a nest site and a roost site, respectively. Radiocarbon dates obtained from the bones indicate that eagle owls lived in the collapsing bath complex during the second half of the 6th to the beginning of the 7th century AD, before the final abandonment of the town. The MNI of the prey animals found at the nest site, confronted with the daily dietary needs of a female eagle owl and its young, indicates repetitive use of the same place during several years. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
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