New exposure of loess deposits in Boyanychi (Ukraine) — Results of thermoluminescence analyses

The loess site at Boynychi (the Volyn Upland) is of essential importance for the stratigraphy of Middle and Upper Pleistocene in Central Europe. The profile was recently dated by Fedorowicz and Prylypko in 2007 (parallel dating), and by Kusiak in 2009. The Upper Vistulian loesses are much thicker in the exposure from 2009 than in the earlier examined one (2007). The list of results obtained in the Gdańsk, Kiev and Lublin laboratories, respectively, can be divided in two. The first group contains the results obtained for the Horohiv and Korshiv pedocomplexes and for the loess from the penultimate glacial, which separates these pedocomplexes. The results from all laboratories are very similar and rather well describe the real age of dated deposits. The second group contains the widely differing results of dating of the Vistulian loesses. The TL ages obtained by Fedorowicz and Prylypko are considerably older than those obtained by Kusiak in the new exposure. The latter ones excellently correspond to the geologic-stratigraphic interpretation of the profile. Two incompatible series of TL dating results indicate that local variability of loess accumulation conditions in different stages of their formation may have resulted in incomplete luminescence zeroing of mineral material before deposition.     

Luminescence characteristics and dose distributions for quartz and feldspar grains from Mumba rockshelter,Tanzania

Mumba rockshelter is a key archaeological site for the Middle and Later Stone Age occupation of East Africa, but its chronology has remained unresolved. We report the results of a dating study, focussing on the characterisation of the optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL) properties of quartz- and potassium-rich feldspar grains. Quartz has previously proven troublesome for dating in East Africa. We identified five general types of quartz grain behaviour, based on the shapes of their OSL decay and dose–response curves. Dose recovery experiments and measurement of the natural samples revealed particular problems with quartz grains that had hyperbolic dose–response curves, low characteristic saturation doses and anomalously large changes in sensitivity between regenerative-dose cycles. The use of pulsed irradiation during measurement and standard and additional quality-assurance criteria during data analysis reduced the number of grains that suffered from these problems. We applied these procedures to individual grains of quartz from eight samples and, using appropriate statistical models, identified post-depositional mixing in three samples. The remaining samples had scattered equivalent-dose distributions typical of quartz grains that had received variable beta dose rates during burial. Stratigraphically consistent OSL ages were obtained for all but the deepest sample. Feldspar ages were estimated for the latter sample and three other samples, using the elevated temperature IRSL signal that exhibited low rates of anomalous fading. Fading-corrected feldspar ages for the latter three samples are consistent with their single-grain quartz ages, but single-grain dating is needed to address problems of post-depositional mixing.     

Diet,social differentiation and cultural change in Roman Britain: new isotopic evidence from Gloucestershire

This study uses stable isotope analyses (δ¹³C and δ¹⁵N) of human bone collagen to reconstruct the diet of three Romano-British (first to early fifth century AD) populations from Gloucestershire in South West England. Gloucestershire was an important part of Roman Britain with two major administrative centres at Gloucester (Glevum) and Cirencester (Corinium) and numerous smaller settlements and farmsteads. To investigate potential dietary differences between the rural and urban populations of Roman Gloucestershire, we compared human bone collagen stable isotope values from 32 individuals from urban Gloucester with those of 46 individuals from two rural cemeteries at Horcott Quarry and Cotswold Community, respectively. Seven individuals from urban Gloucester were buried in a mass grave; all others were buried in single inhumations. Results show small but significant differences in stable isotope ratios between the urban and rural populations which indicate that the urban population might have consumed slightly more marine and/or freshwater resources than the people living in the rural communities. We interpret this difference as a direct reflection of Rome’s influence on Gloucester’s population and the town’s economic status. Subtle differences in stable isotope ratios were also observed at the site level, as burial practice does correlate with diet in some cases. Overall, the results from this study demonstrate that diet, as reconstructed through stable isotope analysis, is a very sensitive, if settlement-specific, indicator of social differentiation and culture change.     

Sourcing ceramics with portable XRF spectrometers? A comparison with INAA using Mimbres pottery from the American Southwest

Seventy-five intact Mimbres and Jornada pottery sherds from the American Southwest were analyzed by portable XRF and instrumental neutron activation analysis (INAA). Examination of the data demonstrates that INAA and portable XRF results for elements common to both analyses can be used to construct similar compositional groups. When individual compositional groups are compared to one another, it is apparent that unambiguous separation of compositional groups is challenging by portable XRF given (1) the limited number of key discriminating elements that can be measured relative to INAA, and (2) the relative analytical precision and accuracy of portable XRF for measurements of intact heterogeneous ceramics. We conclude that sourcing intact ceramics by portable XRF is challenging and that bulk analytical measurements, such as INAA, remain a better approach for sourcing archaeological pottery.     

The p‐Regions Problem. p‐区域问题

The p‐regions problem involves the aggregation or clustering of n small areas into p spatially contiguous regions while optimizing some criteria. The main objective of this article is to explore possible avenues for formulating this problem as a mixed integer‐programming (MIP) problem. The critical issue in formulating this problem is to ensure that each region is a spatially contiguous cluster of small areas. We introduce three MIP models for solving the p regions problem. Each model minimizes the sum of dissimilarities between all pairs of areas within each region while guaranteeing contiguity. Three strategies designed to ensure contiguity are presented: (1) an adaptation of the Miller, Tucker, and Zemlin tour‐breaking constraints developed for the traveling salesman problem; (2) the use of ordered‐area assignment variables based upon an extension of an approach by Cova and Church for the geographical site design problem; and (3) the use of flow constraints based upon an extension of work by Shirabe. We test the efficacy of each formulation as well as specify a strategy to reduce overall problem size.     

The political economy of maize production and poverty reduction in Zambia: analysis of the last 50 years

Poverty and food security are endemic issues in much of sub-Saharan Africa. To eradicate extreme poverty and hunger in the region remains a key Millennium Development Goal. Many African governments have pursued economic reforms and agricultural policy interventions in order to accelerate economic growth that reduces poverty faster. Agricultural policy regimes in Zambia in the last 50 years (1964–2008) are examined here to better understand their likely impact on food security and poverty, with an emphasis on the political economy of maize subsidy policies. The empirical work draws on secondary sources and an evaluation of farm household data from three villages in the Kasama District of Zambia from 1986/87 and 1992/93 to estimate a two-period econometric model to examine the impact on household welfare in a pre- and post-reform period. The analysis shows that past interventions had mixed effects on enhancing the production of food crops such as maize. While such reforms were politically popular, it did not necessarily translate into household-level productivity or welfare gains in the short term. The political economy of reforms needs to respond to the inherent diversity among the poor rural and urban households. The potential of agriculture to generate a more pro-poor growth process depends on the creation of new market opportunities that most benefit the rural poor. The state should encourage private sector investments for addressing infrastructure constraints to improve market access and accelerate more pro-poor growth through renewed investments in agriculture, rural infrastructure, gender inclusion, smarter subsidies and regional food trade. However, the financing of such investments poses significant challenges. There is a need to address impediments to the effective participation of public private investors to generate more effective poverty reduction and hunger eradication programmes. This article also explores the opportunities for new public–private investments through South–South cooperation and Asia-driven growth for reducing poverty in Zambia.