Distribution in SAR palaeodoses due to spatial heterogeniety of natural beta dose

In luminescence dating of sediments, Mayya et al. (2006) pointed out that at single grain level, the beta dose for quartz grains is heterogeneous. This heterogeneity arises due the fact that the total potassium in sediment is contributed by few feldspar grains with up to 11–14% stoichiometric potassium (Huntley and Baril, 1997). Beta particles have a range of ∼2 mm, which is comparable to grain sizes and inter-grain distances. This fact implies that the spatial fluctuation of beta emitters (K-feldspars) around individual quartz grains results in heterogeneous dose deposition. These fluctuations therefore, lead to an inherent spread in palaeodoses received by individual quartz grains.     

Financial Constraints on the Modernization of the Russian Economy

A British economist examines the main obstacles to economic modernization in the Russian economy. After arguing that increased investment is required if the Russian economy is to undergo significant modernization, he presents a framework for identifying binding constraints on such investment. A number of popular explanations of Russia's persistent underinvestment are considered, with particular emphasis on financial constraints. Recent Russian government proposals to restructure the financial system are then assessed in light of their implications for the wider economic modernization. On the basis of the growth diagnostics framework employed in the paper, the author makes the case that the binding constraint on investment in Russia is the poor quality of domestic financial intermediation.     

ESR dose response of Al center measured in quartz samples from the Yellow River (China): Implications for the dating of Upper Pleistocene sediment

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.     

IT Industrial Development in Taiwan and the Constraints on Environmental Mobilization

Studies in the development of high‐tech industries have shown low levels of community involvement and environmental mobilization. In contrast to the tenets of social movement theories, it seems that the openness of political systems and the tactics of social movements are not enough to lead to increased grassroots environmental resistance in the context of high‐tech development. This article uses the example of high‐tech electronic development in Hsinchu, Taiwan, to examine why and how grassroots activism has been impeded in the past two decades. The article highlights the industrial characteristics and processes within the information technology sector, and analyses existing obstacles to environmental mobilization in the context of a fast‐growing high‐tech economy. It argues that a unique IT development structure has dramatically changed local social characteristics in a way that constrains grassroots mobilization in public social agendas. It also shows how the influential and rapidly expanding IT sector has come to dominate resource‐use in the area, leaving opposing forces more powerless than ever.     

An assessment of the luminescence sensitivity of Australian quartz with respect to sediment history

This study provides a preliminary systematic characterisation of OSL sensitivity, with respect to sediment history, of single grains of Australian quartz from a variety of source rocks and depositional contexts. Samples from two distinct lithologies and with relatively short modern sedimentary histories were compared in an examination of the influence of rock type on OSL sensitivity. Sediments derived from weathered sandstone were found to be brighter than those from metamorphosed schists, suggesting that sensitivity may be inherited from the source rock and its earlier sedimentary history. Secondly, quartz from the same source, but different modes of deposition, was compared to assess the effect on sensitivity of nature of exposure to light during the most recent bleaching event. Quartz grain sensitivity appears not to vary depending on the mode of sediment deposition, suggesting that the nature of exposure to light during deposition is less important in the sensitisation process. This study highlights the complexity and variety of natural sedimentary quartz, demonstrating the limitations of an investigation based solely on OSL sensitivity. Further systematic investigation into the physical, geological and geomorphological characteristics of sediments is proposed to better understand the mechanisms of luminescence sensitisation in quartz.     

Getting close to Rwandans since the genocide: studying everyday life in highly politicized research settings

Research with people in highly politicized research settings illuminates the gap between the images that most African governments strive to represent and the sociopolitical realities of everyday life. This article discusses the opportunities and challenges of doing research in postgenocide Rwanda and is a useful resource for researchers contemplating their own projects under such conditions, whether in Rwanda or elsewhere. It discusses the importance of creating personal relationships and meeting people on their terms, as well as such topics as the identification of the research site, building rapport and trust with respondents, safeguarding anonymity and confidentiality, and working with local research assistants and partners.     

Results of a New Approach to Solving the p-Median Problem with Maximum Distance Constraints

Considerable interest has been directed in the past to developing approaches for solving the p-median problem with maximum distance constraints. All current solution techniques consider potential facilities to be located only at nodes of the network. This paper deals with the solution of this problem under the condition where facility placement is not restricted to nodes. The examples given show that improvement in weighted distance can be obtained by solving the unrestricted site problem. In addition, feasible solutions can be obtained for smaller numbers of facilities than possible by all nodal facility placement.     

Investigation of the temporal change of the sources of Aeolian dust delivered to East Asia using electron spin resonance signals in quartz

The temporal change in the number of oxygen vacancies in quartz was investigated by ob-serving the E1’ center in the atmospheric depositions collected at two cities in Japan in the recent past. The depositions collected at Fukuoka in March show the ESR intensities being correlated with the sum of the number of the days, in the month, on which Kosa was observed while no such correlation was found in the deposition those collected at Akita but a trend of decrease with time. The present results suggest that the number of oxygen vacancies in quartz might be useful to estimate quantitatively the contribution of the dust originated from China to the atmospheric deposition in Japan.     

Subterranean transport and deposition of quartz by ants in sandy sites relevant to age overestimation in optical luminescence dating

An artificial layered sandy site was created using a combination of native sand and colored sand (3 parts native uncolored quartz, 1 part colored quartz) in Apalachicola National Forest near Tallahassee, Florida. Twelve layers of sand, each 1 by 1 m in horizontal extent by 10 cm in thickness were emplaced to a depth of 2 m followed by implantation at the surface of a Florida harvester ant (Pogonomymrex badius) colony (the lower two layers were 50 cm thick). The colony excavated a nest, and after 7 months, the sand layers were excavated to the base to test the hypothesis that sand grains were moved upward within the ant nest without reaching the surface. The ants penetrated 11 of the 12 colored layers reaching a depth of 130 cm. Thirty nine sticky-acetate peels of ant chamber floors were collected and colored sand grains were counted under a microscope. More than 16,000 grains were identified in layers that did not originally host them. Of these, more than 80% were unambiguously moved upward. This means that possibly as many as 54,000 upwardly mobile grains were present (ratio of 3:1 uncolored to colored). In relation to optical luminescence (OSL) dating, this means that grains that would not have been optically zeroed by transport to the surface (defined here as subterranean-transported) were present in abundance, and that if the site was ancient, there would have been found many grains that were older than the layers they presently reside in, even if only one colony of harvester ants had disturbed the layers. This is in addition to the fact that backfilling of chambers and tunnels may contribute even more significantly to the presence of a subterranean-transported component of an OSL sample. We conclude that ants can significantly affect the age distributions in sandy archaeological sites. Multiple examples of such disturbances have been documented in the literature. Most relevant to our results are recent studies of the OSL chronology of Pre-Clovis-age and Palaeoindian age archaeological sites in sandy environments in North America that may have been compromised by ant bioturbation of quartz sand grains. Here we have examined in detail the potential effects of one episode of ant nest-building on the age overestimation of affected sediments. From this we found that as few as 12 episodes of bioturbation involving backfilling of chambers in the same volume of sand could lead to the presence of 1 contaminant grain per 50 grains of sample.     

Constraints on Local Welfare Discretion in an Era of Second‐Order Devolution

Under devolution, state and local governments are expected to use the greater authority granted to them to design new and innovative programs that are tailored to local needs. Existing research on the devolution of welfare programs has reported substantial variation in the policies adopted by states in the wake of welfare reform. However, under second‐order devolution, local governments also gained discretion over welfare services. Some have argued that, while devolution should increase flexibility, local governments face constraints that limit their functional discretion. Using California as an example, I assess whether there is variation in the service priorities adopted by local governments and whether these priorities translate to frontline practices. I show differences in the service priorities of local governments; however, these priorities are not associated with differences in sanctioning or time‐limit exemptions. Thus, while local governments may formally adopt different priorities, state and federal policy choices, as well as client characteristics, may restrict priorities from translating into differences in caseworker behavior.     

The in situ preservation of archaeological remains: using lysimeters to assess the impacts of saturation and seasonality

Recent research has studied the effects of seasonal variability on waterlogged burial environments. In a new approach to the study of archaeological contexts, the use of controlled laboratory conditions via lysimeters has enabled new insights into the nature of short term fluctuations in saturation, and the impact that these can have on burial contexts. In addition, the protocols used have facilitated interesting insights into burial environments and the way in which fluctuations in saturation and seasonality can impact on the contained organic components within them.     

Lithic reduction sequences as an aid to the analysis of Late Stone Age quartz assemblages from the Luano Spring,Chingola, Zambia

This paper describes Late Stone Age assemblages of quartz tools and debitage from sites near Luano Hot Spring, Chingola, Zambia. Formal tools at the Luano rock shelter site suggest a Nachikufan II to Nachikufan III sequence according to the traditional terminology. However, analysis of the debitage demonstrates that all levels of the site represent a single Late Stone Age technological tradition. Differences in formal tool frequencies at this site are better explained as activity facies. The implications of these results for our understanding of local Late Stone Age-Iron Age contacts are discussed.

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Résumé Cet article décrit des ensemblages d'outils et d'éclats de débitage sur quartz de l'Age de la Pierre Récent provenant de sites proches des sources thermales de Luano, près de Chingola, en Zambie. Les outils de l'abri sous roche de Luano suggèrent une séquence allant du Nachikufien II au Nachikufien III selon la terminologie traditionnelle, cependant l'analyse du débitage montre que toutes les couches du gisement correspondent à une seule tradition technologique de l'Age de la Pierre Récent. Dans ce gisement, les différences de fréquences des types d'outils s'expliqueraient par des facies résultant d'activités différentes. Les implications de ces résultats pour l'etude locale des contacts entre l'Age de la Pierre Récent et l'Age du fer sont discutées ici.

     

Characteristics of ESR signals and TLCLs of quartz included in various source rocks and sediments in Japan: A clue to sediment provenance

The variation of electron spin resonance (ESR) signal intensities and thermoluminescence colour images (TLCIs) of quartz was investigated in the present study for various rocks and sediments in Japan, to discuss the possibilities of identifying the sediment provenance. The ESR signal intensity of the E₁’ centre in the same grain size in granitic quartz varies from sample to sample, except for that in Quaternary samples of volcanic sediment, which is very low, close to the noise level. It was found that the diagram, ESR intensities of Al versus Ti-Li centre signal intensities, distinguish volcanic from the same grain size in granitic quartz as well as distinguish individual tephra from another. The TLCIs from volcanic quartz and some granitic quartz samples is almost red and that from the rest of granitic and metamudstone quartz is blue as results of TLCIs although the emission intensities are different. Our results suggest that examining the multiple-centre signal intensities of ESR and the TLCIs are effective to identify the source of quartz and to estimate the sediment provenance.     

Investigations on the degree of bleaching of quartz OSL signals using modern aeolian dust from western Loess Plateau, China

Optically Stimulated Luminescence signal of quartz extracted from modern aeolian dust with known maximum age (about decades) was analyzed in terms of degree of bleaching. The results of dose recovery tests show that the modified double single-aliquot regenerative-dose protocol with the early background subtraction is robust for dating these modern dusts using small aliquots. Bleaching of these dusts is discussed based on the distribution of De values in histograms, scatter plots of D_e versus sensitivity corrected natural OSL signal and comparison between measured D_e and expected D_e. The results indicate that most dusts were completely bleached but some dusts were not completely bleached. For those incompletely bleached dusts in Lanzhou area, the maximum OSL age overestimation is up to ～1 ka, which might be caused by fast deposition accompanied by heavy sand/dust storms. The research suggests that cautions should be given to OSL ages younger than 1 ka in the western China close to deserts.     

Multi-method luminescence investigations on quartz grains of different sizes extracted from a loess section in Southeast Romania interbedding the Campanian Ignimbrite ash layer

In this study we present luminescence investigations of four samples of loess bracketing the Campanian Ignimbrite/Y5 tephra at the Rasova-Valea cu Pietre site, on the eastern bank of the Danube River, southeastern Romania. Investigations involved SAR-OSL dating on aliquots of fine (4–11 μm) and medium-grained (63–90 μm) quartz, as well as single grain analyses on 125–180 μm quartz. Luminescence dating results coupled with glass-shard chemical fingerprinting assign the depositional age and origin of the ash layer to that of the Campanian Ignimbrite/Y5 tephra, dated elsewhere using ⁴⁰Ar/³⁹Ar to 39.28 ± 0.11 ka. Fine-grained (4–11 μm) quartz SAR-OSL analyses yielded ages of 44.4 ± 4.5 ka below the ash, and 41.4 ± 4.2 ka above the ash layer. Single grain analysis on coarse-grained quartz, however, demonstrates that coarse material from these samples exhibits low sensitivity and responds poorly to internal checks of the SAR protocol in comparison with the finer sediment. This observation highlights the need for more extensive investigations into the luminescence properties of quartz as well as into the origin of quartz contributions from different primary sources in the Lower Danube loess steppe.     

Intellectuals,Economic Reform and Social Change: Constraints and Opportunities in the Formation of a Nigerian Technocracy

Crisis and economic reforms have changed the status of intellectuals and their relations with dominant élites and policy makers. Because of the technical and ideological nature of these reforms, policy makers have tended to rely on intellectuals as opposed to bureaucrats to shape the agenda of change. This has converted a large number of intellectuals into technocrats and undermined the fabric of academic life in universities. Nowhere is this more pronounced than in developing countries with a large middle class and an economic or financial base that ensures some degree of independence from the multilateral financial institutions. Understanding the success or failure of economic reforms in developing countries requires some analysis of the complex relations between technocrats and political leaders and the societal constraints both sets of actors face. This article explores these issues in the context of Nigeria, whose academic community, bureaucrats and professionals grew in leaps and bounds in the 1970s, following an oil-induced boom. The crisis of the 1980s led to attempts at economic reform and a highly programmed strategy of political change in which academics played a leading role. The article examines the effectiveness of intellectuals in government, and compares the Nigeria case with technocratic experiments in Ghana, Botswana and Côte d?Ivoire.