超声波技术在大佛寺石窟石质保护中的应用

介绍超声波探测在石质文物风化评价、化学加固效果评价及其裂隙研究方面的应用,并将其结果与目前常用的方法进行了比较。     

Method-dependent variations in stable isotope results for structural carbonate in bone bioapatite

Stable carbon and oxygen isotope values (δ¹³C, δ¹⁸O) were obtained for structural carbonate in the bioapatite of archaeological bones from Guatemala and Sudan using several common analytical methods. For the Sudan samples, the different methods produced δ¹³C values within ±0.1‰ and δ¹⁸O values within ±0.7‰, on average. The isotopic results for the Guatemala samples were similar in reproducibility to the Sudan samples when obtained using methods that employed lower reaction temperatures and reactions in sealed vessels. However, many Guatemala samples had highly variable and extremely low δ¹⁸O values when reacted at higher temperatures in vessels that remained open to cryogenic traps. The latter arrangement caused reaction products to be removed immediately upon their production. The anomalously low δ¹⁸O values are related to the production of a contaminant gas that causes the m/z 46/44 ratio to be lowered, either by adding to the m/z 44 peak or subtracting from the m/z 46 peak. That said, potential contaminant materials were not detectable in “anomalous” bones using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, or inductively-coupled plasma atomic emission spectroscopy. However, subtle structural and chemical differences between “normal” and “anomalous” samples were observed, most notably in the FTIR ν₂ CO₃ domain. We suggest that these changes promote volatilization of an oxyphosphorus compound and oxygen isotope fractionation between PO⁻ derived from this compound and CO₂ derived from bone carbonate. Production of the contaminant gas and the related “anomalous” δ¹⁸O values is reversible if the reaction occurs within a sealed vessel for a sufficient period of time, which allows a “back-reaction” to occur.     

Why are cut mark frequencies in archaeofaunal assemblages so variable? A multivariate analysis

Cut mark frequencies in archaeological faunal assemblages are so variable that their use has recently created some skepticism. The present study analyses this variability using multivariate statistics on a set of 14 variables that involve differential skeletal element representation, fragmentation processes, carnivore ravaging impact, carcass size and tool type. All these variables affect the resulting cut mark frequencies reported in archaeological sites. A large sample of archaeofaunal assemblages has been used for this study. It was concluded that the best estimator of cut mark frequency in any given assemblage is the percentage of cut-marked long bone specimens (probably due to its better preservation than other anatomical areas), which is determined by fragmentation and carnivore ravaging. Carcass size and tool type also play a major role in differences in cut mark frequencies. Fragmentation is also a key variable determining the abundance of cut-marked specimens. It is argued that general cut mark percentages are of limited value, given the number of variables that determine them, and that a more heuristic approach involves quantifying cut marks in a qualitative manner.     

An X-ray Diffraction (XRD) and X-ray Fluorescence (XRF) investigation in human and animal fossil bones from Holocene to Middle Triassic

We examined by Rietveld refinement of X-ray Diffraction patterns a series of 61 human and animal fossil bones in an age range from present time to Middle Triassic (around 245 Ma). This approach, supplemented by elemental analysis according to X-ray Fluorescence, has permitted to obtain a quantitative evaluation of the mineralogical phases in the specimens, thus allowing to reconstruct the mineralization process involved. Concerning the apatite phase, after adopting a monoclinic geometry for the unit cell, the method permits to determine with fair degree of precision the unit cell volume, which is found to decrease in relatively short geological times as a function of the fluorine substitution process for the hydroxyl group –OH. After excluding the role of a high-temperature fire treatment to the bones, it is found that a certain linear correlation may exist over the geological time scale involved between the age of the specimen and the average crystallite size. This observation permits to use the XRD pattern as an evaluation of the age of the fossil, although the stratigraphic observations, where available, remain as the main reliable source for dating such biomaterials. The uncertainty related to this age estimation may be hardly better than 15–20% in absolute, because of various assumptions involved in the XRD methodology used and in the variability of the burial environment that may be subjected to discontinuous changes over the very long time of deposition.     

宋代兵力部署考察

北宋前期的军队部署实行内外相制原则,京师兵力和其他地方兵力相等,以互相牵制。这一原则在宋神宗时发生变化,大部兵力分布在西北地区,而京师地区兵力不断减少,北宋末只剩数万。南宋前期,恢复实行了内外相制的兵力部署原则,临安地区驻兵最强,后期再次颠倒,重兵多在边防。无论北宋还是南宋,兵力部署在地域上都是重北轻南,南宋政府对南部内地的防卫尤弱于北宋。北宋的东线防御立足于兵,并不依赖黄河天险,重兵都在黄河以北;南宋重兵分布在长江沿线,对天险的依赖加强,但几乎放弃了边界的另一天险——淮河,表明其防御是消极的以守为主的战略。     

High-throughput mass spectrometric analysis of 1400-year-old mycolic acids as biomarkers for ancient tuberculosis infection

The cell wall of mycobacteria includes an unusual outer membrane of extremely low permeability. This cell envelope consists of a characteristic cell wall skeleton, a mycoloyl arabinogalactan peptidoglycan complex, and related hydrophobic components that contribute to the cell surface properties. In this study 1400-year-old mycolic acids as unique tuberculosis biomarkers have been extracted and identified for the first time by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) and Fourier transform infrared spectroscopy (FT-IR). The data suggest that the MALDI TOF MS has potential as a rapid and reproducible technique for the detection and identification of ancient mycobacterial infections.     

Fluvial transport of bovid long bones fragmented by the feeding activities of hominins and carnivores

This study explores the hydraulic transportability of bovid long bone fragments created through hominin and carnivore carcass consumption in order to determine the effect of fluvial transport on the incidences of hominin- and carnivore-induced bone surface modifications. Transportability was determined using an oval race track flume and 311 long bone fragments from modern control collections of hominin- and carnivore-modified bone. Results show that the fluvial transport of long bone fragments is predicted by animal size class and bone specimen size, as measured by maximum cortical thickness, maximum length, and maximum width. All of these variables can be measured on fossil specimens. Long bone portion (midshaft, near-epiphysis, and epiphysis) does not affect transport and hydraulic transport does not substantially modify the incidences of tooth, percussion, and cut marking in transported or lag assemblages in low energy fluvial environments. Implications of this study are: 1) animal size classes, and cortical thickness, length, and width of long bone fragments can be used to identify fluvial winnowing in fossil assemblages; 2) analyses concerning the relative timing of hominin and carnivore carcass consumption based on the proportions of long bone fragments bearing tooth, percussion, or cut marks can be meaningfully applied to fossil assemblages deposited in low-energy fluvial environments.     

Taphonomic identification of cut marks made with lithic handaxes: an experimental study

Recent experimental studies have developed new diagnostic criteria to differentiate between trampling and cut marks. Within cut marks, these diagnostic criteria have been useful to differentiate between marks made with simple and retouched flakes. The present study expands the application of these criteria using a multivariate analysis to discriminate marks created with handaxes from those made with stone tool flakes. A discriminant analysis resulted in a selection of specific variables, which can successfully differentiate cut marks made with handaxes from those created with retouched flakes in more than 80% of occasions. The utility of this analogical taphonomic signature created by handaxes is discussed in the light of their potential value as butchering tools.     

Paleodietary analysis of the prehistoric population of the Canary Islands inferred from stable isotopes (carbon,nitrogen and hydrogen) in bone collagen

Nitrogen and carbon isotope compositions were measured in the bone collagen from a total of 86 prehispanic samples of the Canary Islands, and hydrogen in 70, all of them with enough amount of bone collagen, and adequate N and C content. These samples belong to prehistoric population of El Hierro (n = 27), Tenerife (n = 18), and Gran Canaria (n = 41). Isotope compositions were also obtained for prehistoric and modern food resources that were likely consumed by these people. Marked differences were observed among the three islands regarding the three isotopes analyzed: the δ¹⁵N values were highest among the population of Gran Canaria (10.8‰ ± 0.9‰), who also showed the highest δD values (7 ± 8‰). The population of El Hierro showed the highest δ¹³C values (−18.6‰ ± 0.7‰). These data suggest a high consumption of marine products by the population from El Hierro, and also an important consumption of terrestrial meat or marine, piscivore fish, by the population from Gran Canaria, together with domesticated C₃ plants (barley and/or wheat), fruits of Ficus carica and other wild species, and goat products. Additionally, marked differences were observed between men and women, which suggest that women consumed a more vegetal-based diet, a finding which is in agreement with the higher proportion of teeth with carious lesions among women.     

殷周时期的“举族”及其相关问题

<正>~~