The archaeology of radiocarbon accelerator dating

Accelerator mass spectrometry (AMS) allows radiocarbon dating to be carried out by direct counting of¹⁴C atoms, rather than the conventional counting of radioactive disintegrations. The result is that samples up to 1000 times smaller can be handled. The approach was tested in principle by 1977 and for archaeological operation by 1983. More than 2000 samples per year are now being dated worldwide. The machines can now operate to about ± 80 years or better. Dates older than 40,000 years have not yet been achieved, but the ability to use small samples has already had considerable impact on dating the period 10,000–30,000 years ago. Bone is an ideal material for the new technique, since amino acids can normally be isolated and purified from gram-size samples. Studies of the origins of domestication are aided by the dating of individual grains and seeds. Because small samples can be mobile in the soil, careful sample selection strategies and procedures are required. The full impact of the technique can be assessed only through the rapid and comprehensive publication of archaeological results.     

Potential Use of Foamed Mortar (FM) for Thermal Upgrading of Chinese Traditional Hui-Style Residences

The Hui-style residence is an important architectural heritage of China. The hollow wall structures are widely used to build its exterior wall system. However, the thermal performance of the hollow wall is no longer able to meet the new energy-saving and environmental requirement. This article describes a laboratory study of the development of foamed mortar (FM), with the potential for use in thermal upgrading of the Hui-style hollow wall system without dramatically changing its traditional structure. The key early age, physical, mechanical and thermal properties were systematically measured. Two extended models were respectively developed to calculate compressive strength and thermal conductivity, as a function of porosity. Environment chamber test was also employed to investigate the effectiveness of this novel thermal upgrading approach and the results show that filling the voids with FM can effectively improve the overall thermal resistance of the hollow wall system by 44%, which is almost equal to the overall thermal resistance when using the more expensive commercial inorganic stucco system. In addition, the combination of these two methods yielded an overall thermal resistance of 0.701 m²·K/W, which is even higher than 0.67 m²·K/W for the code required in the hot summer/cold winter climate zone.     

Spatial variation in cervical cancer screening participation and outcomes among Indigenous and non‐Indigenous Australians in Queensland

Indigenous women continue to experience a disproportionately higher burden of cervical cancer than non‐Indigenous women in Australia. The National Indigenous Cervical Screening Project used probabilistic record linkage to combine population‐based administrative databases and identify Indigenous women on Pap Smear Registers. This study aimed to quantify the spatial variation by local government areas (LGAs) for Indigenous and non‐Indigenous women in Queensland in cervical screening participation rates and related outcomes. Empirical Bayes local geostatistical smoothing was performed to reduce the likelihood of spurious variation between small areas. The cohort included 1,091,260 women (2 per cent Indigenous) aged 20 to 69 with 2,393,708 Pap smears between 2006 and 2011. Indigenous women had smoothed LGA‐specific 5‐year participation rates (interquartile range (IQR) 38.9–53.3 per 100 eligible women) consistently lower than non‐Indigenous women (IQR 80.7–85.3). The non‐overlapping confidence intervals of these rates suggest that the Indigenous differential was significant. Compared with Indigenous women, non‐Indigenous women had consistently lower and more stable prevalence rates of histologically confirmed high grade abnormalities (IQR 8.0–10.1 versus 15.0–21.3 per 1,000 screened women). Although the LGA‐specific rates also suggest that a higher proportion of non‐Indigenous women were followed‐up within two months of an abnormal screening result, the wide confidence intervals for these estimates limit our ability to draw definitive conclusions about spatial patterns for this outcome. These findings highlight the importance of continued monitoring and ongoing efforts to identify drivers of these patterns and develop effective strategies to improve participation and potentially reduce the cervical cancer burden among Indigenous women.     

Exponentially decreasing tooth growth rate in horse teeth: implications for isotopic analyses

A range of archaeological and palaeoclimatic studies use isotopic analyses of ungulate hypsodont tooth enamel. Such studies commonly assume a constant growth rate, though this has not been fully tested. Here, we use stable isotope analyses of sequential enamel samples to study horse tooth growth. We fit the data using models corresponding to constant and exponentially decreasing rates of growth, and compare the results to metrical data showing the geometry and timing of apposition. The results indicate enamel apposition and maturation advances at an exponentially decreasing rate. An understanding of this variable growth rate is crucial for interpreting isotopic data from equid teeth.     

Real‐time quadrupole mass spectrometer analysis of gas in borehole fluid samples acquired using the U‐tube sampling methodology

Sampling of fluids in deep boreholes is challenging because of the necessity of minimizing external contamination and maintaining sample integrity during recovery. The U‐tube sampling methodology was developed to collect large volume, multiphase samples at in situ pressures. As a permanent or semi‐permanent installation, the U‐tube can be used for rapidly acquiring multiple samples or it may be installed for long‐term monitoring applications. The U‐tube was first deployed in Liberty County, TX to monitor crosswell CO₂ injection as part of the Frio CO₂ sequestration experiment. Analysis of gases (dissolved or separate phase) was performed in the field using a quadrupole mass spectrometer, which served as the basis for determining the arrival of the CO₂ plume. The presence of oxygen and argon in elevated concentrations, along with reduced methane concentration, indicates sample alteration caused by the introduction of surface fluids during borehole completion. Despite producing the well to eliminate non‐native fluids, measurements demonstrate that contamination persists until the immiscible CO₂ injection swept formation fluid into the observation wellbore.     

Stone Age fishhooks – how were they dimensioned? Morphology,strength test,and breakage pattern of Neolithic bone fishhooks from Ajvide,Gotland, Sweden

The late Stone Age Pitted Ware site at Ajvide, Gotland, in the Baltic Sea, Sweden, has revealed a large deposit of fishbone and approximately 400 bone fishhooks, complete and incomplete. Cod (Gadus morhua), which is one of the most abundant fish species in the bone assemblage, was probably caught with hook and line fishing. To investigate the fishhooks' field of application, a morphological and morphometric study was performed on 384 available hooks. Two sets of replicas made of four selected original fishhooks were submitted to a strength test. A breakage study of the incomplete hooks in comparison with the strength-tested hooks was carried out in order to distinguish fresh breaks from dry breaks. It seems that a certain morphology for fishhooks was preferred at Ajvide, indicating they were produced by skilled craftsmen for special usage. The strength test showed that the hooks had a weight bearing capacity more than the average size of cod caught at Ajvide. Using results of these tests, we predicted that the mean breaking strength of 46 intact Ajvide hooks was 96.6 ± 26.1 (s.d.) Newtons (equivalent to 9.85 ± 2.7 kg). The design of fishhooks changed somewhat over time, being slightly larger in the oldest layers of the site. The breakage patterns of the hooks show that the bow was the most common area of breakage. The design and weight bearing capacity of the hooks point to a specialized cod fishery from boats in deep water.     

An investigation of soil phosphorus distribution within occupation deposits from a Romano-British hut group

A simple scheme for soil sampling and subsequent analysis for total soil phosphorus using perchloric acid digestion is described and its application illustrated by samples from the native farmstead of the Roman period at Cefn Graeanog in North Wales. The floor deposits of three distinctive buildings were analysed, and the data obtained enhanced by Trend Surface Analysis to produce generalized maps of the phosphorus distribution, together with levels of significance of such distribution patterns. These were then used to clarify the details of the interpretation of the usage of the various types of building. Data for soil phosphorus concentration clearly reveal the pattern of erosion of constructed floors, the presence of features such as hearths and drains, and can be used to reveal patterns not otherwise discernible by excavation techniques.     

The use of multiple discriminant analysis in classifying prehistoric phytolith assemblages recovered from cooking residues

In the investigation of the dispersal of maize (Zea mays ssp. mays) from south-central Mexico to the northern and southern limits of agriculture in the Western Hemisphere archaeologists and paleoethnobotanists are increasingly turning to the microbotanical record. Recent analysis of phytolith assemblages from charred cooking residues on pottery sherds in central New York recovered using 209 rondel phytolith variables has identified maize as early as 2270 ± 35 B.P. In this article we use discriminant analysis to re-classify these rondel phytolith assemblages resulting in only seven variables. The results are consistent with those achieved earlier using many more variables and a less formal statistical approach in terms of classification and in similarity of the original and reduced data matrix as seen by the Mantel test and cluster analyses.     

西部十二省、自治区、直辖市旅游竞争力的组合评价

对一个地区的旅游竞争力进行评价有助于客观地了解该地区旅游业的发展状况,而科学合理的评价依赖于评价指标和评价方法的选择。本文提出了合理选择指标的原则,并在所构建的旅游竞争力评价指标体系中引入了＂软＂指标。由于单一评价模型的评价结果各不相同,本文引入组合评价模型对西部十二省、自治区、直辖市的旅游竞争力进行评价,然后采用斯皮尔曼等级相关系数对组合评价结果进行检验,结果显示本文采用的组合评价方法与其它评价方法的一致性最高,说明该方法能比较客观综合地反映旅游竞争力状况。最后,通过聚类分析,进一步验证了本文方法的有效性。     

基于价值转移方法的我国游憩活动价值评价

鉴于目前我国在构建价值转移模型中存在的限制因素,本文采用基于Meta分析的价值转移方法并尝试利用国外游憩活动价值评价的实证研究结果,构建基于Meta分析的国际间价值函数转移模型,估算了我国10种游憩活动的日平均消费者剩余.通过将价值转移模型估算的游憩活动价值“转移值”与国内97个游憩价值评价的“真实值”做比较,对价值转移模型的有效性和可靠性进行统计检验,平均转移误差为18.74％.最后,总结了提高我国Meta回归价值转移模型的具体、可操作性方法及途径.