SITE AMPLIFICATION FACTOR IN ANCHORAGE,ALASKA BASED ON LONG PERIOD MICROTREMORS

Long period microtremors with periods ranging from 0.5 to 10 seconds were measured in the Anchorage metropolitan area. Two horizontal components of motion were recorded at 81 sites uniformly distributed throughout the basin with spatial resolution of about 2 km. Recording at each site was done for 300 seconds with a sampling rate of 20 Hz. Repeated measurements were performed at a bedrock reference site simultaneously with the measurements in the field. The measurements were completed in six days. In addition, multiple recordings were obtained concurrently at the reference bedrock site and a sediment site. Based on these measurements the Fourier spectra were calculated for each of the site. Ground motion amplification is determined in terms of spectral ratio of horizontal spectral amplitudes at a sediment site and the reference bedrock site. Mean spectral ratio contours were evaluated for different period bands. The results show that for period band 3 to 5 seconds the spectral ratio contours agree well with the ground failure susceptiblity map of Anchorage.     

GROUND MOTION DOMINANT FREQUENCY EFFECT ON THE DESIGN OF MULTIPLE TUNED MASS DAMPERS

Utilising the Kanai-Tajimi and Clough-Penzien spectrums and the pseudo-excitation algorithm in the frequency domain, parametric study is performed to examine the effect of the dominant frequency of ground motion on the optimum parameters and effective-ness of multiple tuned mass dampers (MTMD) with identical stiffness and damping coefficient but with unequal mass. The examination of the optimum parameters is con-ducted through the minimisation of the minimum values of the maximum displacement and acceleration dynamic magnification factors of the structure with the MTMD. The optimum parameters of the MTMD include the optimum frequency spacing reflecting the robustness, the average damping ratio and the tuning frequency ratio. Minimisation of the minimum values of the maximum displacement and acceleration dynamic mag-nification factors, nondimensionalised respectively by the maximum displacement and acceleration dynamic magnification factors of the structure without the MTMD, is used to measure the effectiveness of the MTMD. The results indicate that in the two cases where both the total mass ratio is below 0.02 and the total mass ratio is above 0.02, but the dominant frequency ratio of ground motion is below unity (including unity), the earthquake ground motion can be modelled by a white noise. It is worth noting, however, that for the total mass ratio above 0.02, the Kanai-Tajimi Spectrum or Clough-Penzien spectrum needs to be employed to design the MTMD for seismic structures in situations where the dominant frequency ratio of ground motion is beyond unity.     

SEISMIC HAZARD ASSESSMENT OF UNITED ARAB EMIRATES AND ITS SURROUNDINGS

This paper presents the seismic hazard assessment and seismic zoning of the United Arab Emirates (UAE) and its surroundings based on the probabilistic approach. The area that has been studied lies between 50°E-60°E and 20°N-30°N and spans several Gulf countries. First, the tectonics of the area and its surroundings is reviewed. An updated catalogue, containing both historical and instrumental events is used. Seismic source regions are modelled and relationships between earthquake magnitude and earthquake frequency is established. A modified attenuation relation for Zagros region is adopted. Seismic hazard assessment is then carried out for 20 km interval grid points. Seismic hazard maps of the studied area based on probable Peak Ground Acceleration (PGA) for 10% probability of exceedance for time-spans of 50, 100 and 200 years are shown. A seismic zone map is also shown for a 475-year return period. Although the results of the seismic hazard assessment indicated that UAE has moderate to low seismic hazard levels, nevertheless high seismic activities in the northern part of UAE warrant attention. The northern Emirates region is the most seismically active part of UAE. The PGA on bedrock in this region ranges between 0.22 g for a return period of 475 years to 0.38 g for a return period of 1900 years. This magnitude of PGA, together with amplification from local site effect, can cause structural damage to key structures and lifeline systems.     

A sequence of inland desert settlement in the Oman peninsula: 2008–2009 excavations at Saruq al‐Hadid,Dubai, UAE

The 2008–2009 excavations conducted by the Dubai Desert Survey at Saruq al‐Hadid, Dubai, have transformed our interpretation of the site from an Iron Age bronze production centre to a site with multiple occupations over the course of more than three millennia; they underline the importance of this site for understanding land use and settlement patterns in the deserts of the Oman peninsula. Saruq al‐Hadid probably began as an oasis site where nomadic pastoralists during the Umm an‐Nar and Wadi Suq periods camped and took advantage of a relatively well‐watered landscape. In contrast, Iron Age remains at the site do not bear any definite signs of settlement per se; instead, the material culture suggests that Saruq al‐Hadid may have been one of several sites in south‐east Arabia that were dedicated to a snake cult. The site is capped by waste from an intensive metalworking operation that appears to have taken place during the later first millennium BC. Iron age and later remains from the site tie Saruq al‐Hadid to a regional network of settlement and trade centres and suggest that, like the mountain piedmont and coasts, the sandy desert expanses of the Oman peninsula held economic and ritual importance in the overall landscape.     

Mano size,stable carbon isotope ratios,and macrobotanical remains as multiple lines of evidence of maize dependence in the American southwest

While the level of agricultural dependence affects many aspects of human adaptation, estimating levels of dependence on maize through traditional archaeological techniques is problematic. Here we compare various measurements of manos (e.g., grinding surface area), macrobotanical evidence of maize use, and human collagen stable carbon isotope values from six regions of the American Southwest, encompassing 16 phases, as a means of assessing the power and limits of each approach for considering agricultural dependence. The analysis of each data class is considered separately, taking into account formation processes and arguments linking data and inferences. Correlations among the three data classes suggest that mano area and maize ubiquity can be considered ordinal measures of agricultural dependence, but Southwestern stable carbon isotope data have the analytical potential only to discriminate between little or no maize use and substantial maize use. The formation processes and linking arguments associated with each method must be considered when multiple lines of evidence are integrated in order to make sound behavioral inferences. Our results suggest that there were at least three patterns in the adoption of farming in the Southwest: early substantial use followed by continuous increasing maize dependence, initial intensive dependence with little change in later periods, and a long period of minor use followed by substantial dependence.     

The relationship between school ground design and intensity of physical activity

In this study, we investigated the relationship between school ground design and children's physical activity levels. In particular, we were interested in understanding the contribution of ‘green’ school ground design to physical activity levels. Data for this study were collected at an elementary school in Australia and in Canada. At each school, scans of Target Areas were completed to record the students' location and intensity of physical activity, based on the System for Observing Play and Leisure Activity in Youth (SOPLAY) (Australia: 23 scans, 6 Target Areas; Canada: 18 scans, 7 Target Areas). At both schools, the highest percentage of children present was engaged in vigorous physical activity on the manufactured equipment (42% of children/scan). Similarly, at both schools, the green area encouraged the highest percentage of children present to be engaged in moderate physical activity (47% of Australian children/scan, 51% of Canadian children/scan). The patterns of sedentary behavior differed slightly between countries. At the Australian school, the paved sporting courts (57%) and the paved canteen courtyard (50.5%) promoted the highest degree of sedentary play. At the Canadian school, the treed grassy berm (42%) and the treed concrete steps (43%) encouraged the highest percentage of sedentary behavior, followed by the open asphalt (34%). These results are also discussed in light of gender distribution. We conclude with a discussion of the design and cultural factors that influence children's physical activity on school grounds. We argue that if school grounds are to realize their potential to promote physical activity, they should include a greater diversity of design features and ‘green’ elements that engage children of varying interests and abilities in active play.     

Microscopic examination of ground sections – a simple method for distinguishing between bone and antler?

Both bones and antlers have been used throughout history for manufacturing various products. Therefore, archaeologists often have to distinguish between these materials. The more the raw material (bone or antler) has been treated, the more complicated it is to distinguish. For this study, recent macerated and archaeological samples of bone and antler and their products have been compared. Antler is usually very easy to distinguish based on the characteristic surface structure; however, the original surface is not preserved in all artefacts. The inner surface of the diaphysis of long bones is mostly compact with prominent trabeculae and lamellae, whereas, after removal of the spongiosa, the inner surface of antler is characterised by numerous grooves. Sometimes, however, artefacts are found which are composed only of the compact bone substance, without inner and outer surfaces, and it is not possible to distinguish between bones and antlers macroscopically. Haversian systems can be found in histological and ground sections of both bones and antlers. In contrast to bones, antlers have few interstitial lamellae. The osteons of antler seem to be smaller and to consist of fewer layers than those of bone. Inner and outer circumferential lamellae cannot be distinguished in antlers. Although microscopic examination of sectioned samples does not allow distinction between bones and antlers in every case, it represents a valuable additional tool for distinguishing between these two materials in historic artefacts. Copyright © 2007 John Wiley & Sons, Ltd.     

The Value of Rents: Global Commodity Chains and Small Cocoa Producers in Ecuador

Drawing on the Marxian theory of ground rent, this paper develops an analysis of “global commodity chains” (GCCs) with agrarian roots. There is an acknowledgement that the concentrated downstream governance of primary commodity‐based GCCs has created a set of “asymmetrical” power relations which blocks the transmission of value upstream towards small producers. This paper argues that this research under‐specifies what is meant by value and rent, and in doing so marginalises the analysis of value production before its journey through inter‐firm relations. We demonstrate the importance of theorising the value constitution of commodities produced on the land and the forces that contest the payment of ground rent and thereby shape the geography of GCCs. Based on empirical research conducted around Ecuador's “post‐neoliberal” cocoa re‐activation plan, we identify the class politics and production mechanisms through which value and rent escapes the hands of a stratified network of small owner producers.     

The Middle Ground, “Middle Ground Moments,” and Accommodation in the Study of Later Qing Borderland History

This article examines Richard White’s concept of the “middle ground” and its prospective application to the study of China’s Qing (1644–1911) borderlands from the late eighteenth century. It argues that although White’s model, in its specific formulation, is problematic to apply due to the dissimilarity of Qing conditions, it yet has value and can be adapted. One possibility is advanced in the notion of “middle ground moments,” briefly explored in the cases of Shaanxi’s Dabashan highlands in a “population boom,” Hunan’s Miao Frontier in the “fog of war,” and Xinjiang’s Kashgar crossroads during the “fall of empires.” Focusing on group exchange, adaptation, and hybridization offers insight into regional cultural creation, as well as a means to question received narratives of breakdown, pacification, resistance, or Great Game struggle. Such modeling, and shared attention to accommodation perspectives generally, also presents a space for dialogue across the New Qing History and Chinese nationalist divide in Qing frontier studies.     

商周青铜器铸后制铭工艺考证

学界普遍认为商周时期青铜器的铸造铭文早于铸后制铭,并认为铸后制铭技术只出现在西周晚期以后。本文通过对商周时期若干铸后制铭青铜器的研究发现,铸后制铭可分为錾铭、刻铭与琢磨铭文三类,后两类的出现与应用不晚于铸造铭文。这些技术脱胎于夏商时期的玉器加工工艺,当与甲骨文的契刻技术同源,工匠至迟在商代晚期就已掌握,但出于生产效率与容错代价方面的考虑,选择了出现较晚但更为节省时间和人力的铸造铭文技术。铸后制铭因为其本身的缺陷,只作为一种边缘技术长期存在。