古建筑木构件的防火处理与性能研究

古建筑具有重要的文化价值和经济价值,是重要的不可再生文化遗产。中国的古建筑以木为主要结构,而木结构的耐火等级低,这就造成了中国古建筑面临了一个极大的隐患——火灾,因此对古建筑木构件的防火处理与性能的研究迫在眉睫。为此,试验选取3种不同的木材和5种不同的阻燃剂作为研究对象,首先对涂覆不同阻燃剂的木材进行表观特征测量,然后分别采用热重分析法和扫描电子显微镜测试技术进行表征测试,最后分析阻燃木材的各种力学性能测试。研究结果表明:喷涂阻燃剂的木材其性能效果均优于未喷涂的木材。特别针对未涂油漆的原木构件,可以采用有机磷杂环阻燃剂或磷—氮类阻燃剂;普通油漆的木构件则适用于磷—氮类阻燃剂,而处理桐油木构件应用磷—氮类阻燃剂或阻燃油。     

Ancient DNA supports lineage replacement in European dog gene pool: insight into Neolithic southeast France

We report palaeogenetic analysis of domesticated dog (Canis familiaris) remains excavated from three archaeological sites from southeast France and dating from Middle Neolithic. Ancient DNA analysis was attempted on teeth and bone samples taken from 11 dogs. Three 266-base-pair fragments of the mitochondrial genome Hypervariable Region I (HVR-I) could be retrieved and revealed two haplotypes belonging to HVR-I lineage C. These three sequences were compared to the sequences of Swedish and Italian Neolithic dogs and permitted to confirm that clade C was largely represented all over Western Europe during this period. One haplotype defined in Neolithic French dog was observed for the first time in Canis mtDNA, underlining the loss of mitochondrial diversity in Europe since the Neolithic. Finally, these results point out mitochondrial lineage replacement in Europe, since lineage C represents only 5% of extant European dogs. Altogether, these results support the proposition that palaeogenetic studies are essential for the reconstruction of the past demographic history and the domestication process of dogs.     

First ancient bovine DNA evidence from India: difficult but not impossible

Ancient DNA isolation from the tropical countries has been shown to be very difficult in the past. Here for the first time we have been successful in isolating ancient DNA from Indian cattle samples. We were able to obtain DNA and sequence the partial mitochondrial D-loop in 3 of the 15 bovine fossil samples ranging in age from 2000 BC to 1000 AD, and were able to further identify the most recent sample as being of Bos indicus origin. Our results on ancient DNA extraction from India will encourage other researchers in this field to carry out further studies of ancient DNA from Indian bovine samples. Our results represent the first successful extraction and amplification of bovine ancient DNA from India, and thus may pave the road for a better understanding of demographic and historical processes of cattle domestication that has taken place in this region.     

Oaks,tree-rings and wooden cultural heritage: a review of the main characteristics and applications of oak dendrochronology in Europe

We overview the recent development of oak dendrochronology in Europe related to archaeology and art-history. Tree-ring series of European oaks (Quercus robur and Q. petraea) have provided a reliable framework for chronometric dating and reconstruction of past climate and environment. To date, long oak chronologies cover almost the entire Holocene, up to 8480 BC and the network over the entire area in which the two oaks grow is being improved. We present the main characteristics of oak ring series and discuss the latest methodological advances in defining the calendar year in which the tree-rings were formed and in interpreting such dating in terms of the age of a wooden object. Dendrochronology has established itself as a standard dating tool and has been applied in a wide variety of (pre-)historical studies. Archaeological wood, historical buildings, works of art (such as panel paintings and sculptures) have been successfully investigated. Recent advances in dendro-provenancing have helped to obtain more information on the timber trade in the past. Information on past forest structures, silviculture and timber use have become available through scrutinizing historical and contemporary ring-width patterns.     

Ancient DNA reveals a major genetic change during the transition from hunting economy to reindeer husbandry in northern Scandinavia

The timing and origin of reindeer domestication has been highly debated. Recent molecular analyses show several mitochondrial lineages of domestic reindeer across Eurasia suggesting different origins of Fennoscandian and Siberian domestic reindeer. In order to investigate the origin of domestic Fennoscandian reindeer, we sequenced a mitochondrial control region fragment of 68 ancient reindeer remains from archaeological sites in Finnmark, the major county for extant reindeer husbandry in Norway, spanning from ca. BC 3400 to AD 1800. The majority of the Stone and Iron Age reindeer assemblages in Finnmark are from settlements in the eastern part of the county, in the Varangerfjord area. The reindeer remains from these settlements show affiliation to the large and complex Beringian haplotype cluster, found in extant reindeer from the Kola Peninsula to north-eastern Russia. A distinct haplotype shift is observed in the late medieval period, when the typical haplotype signatures of extant domestic Fennoscandian reindeer appeared in coastal regions of both eastern and western Finnmark. These haplotypes were not found among the Stone and Iron Age wild reindeer samples of Finnmark, suggesting that this population was not ancestral to extant domestic reindeer of Fennoscandia.     

Tikal timbers and temples: ancient Maya agroforestry and the end of time

Tikal, a major lowland Maya civic-ceremonial center in the heart of the Petén region of Central America, relied heavily on the adjacent lowland rainforest as a resource base for fuel and construction materials. In this study, we analyzed 135 wood samples from timbers used in the construction of all six of the city's major temples as well as two major palaces to determine which tree species were being exploited and to better understand ancient Maya agroforestry practices during the Late Classic period. We found evidence for a change in preference from the large-growing, upland forest species, Manilkara zapota, to a seasonal wetland species Haematoxylon campechianum in A.D. 741 as well as a decrease in lintel beam widths over time. Though M. zapota later returned as the wood species of choice in A.D. 810, beam widths were found to be significantly smaller. These findings concur with models that hypothesize widespread deforestation during the Late Classic period and indicate a declining forest resource base by the 9th century A.D. Because of the many large timbers available for temple construction in the 8th century, some system of forest conservation is indicated for the ancient Maya prior to the Late Classic period.     

Seasoned or green? Radial cracks analysis as a method for identifying the use of green wood as fuel in archaeological charcoal

For several years, sociological questions have been central in anthracology. The development of socio-economic approaches based on the recognition of anatomical signatures in wood has made it possible to focus on topics related to firewood use and its management. The presence of radial cracks (RC) on archaeological charcoal is generally interpreted as the result of the burning of green wood. The present study proposes a verification of this theory by the experimental combustion of seasoned and green wood of Scots Pine (Pinus sylvestris L.). Experimenting with this species was a research priority since it was the dominant taxon (representing 80-100% of the charcoal remains) identified in the Palaeolithic European sites under consideration.The experiments were conducted using two different methods: (i) inside a muffle furnace that allowed us to control the combustions, but in which the combustion process is quite different from most archaeological situations and (ii) in an open fireplace, less controllable but closer to the archaeological conditions. The systematic quantification of the number, length and width of the radial cracks (RC) measured on the transversal sections of the experimental samples demonstrates that (i) radial cracks occur independently of the moisture content of the wood before the combustion (on green and seasoned wood); (ii) however, the average number of radial cracks (RC/cm²) allows distinguishing seasoned from green wood; (iii) in the muffle furnace, the size of the RC appeared to be a good criterion for discriminating seasoned and green wood, but this observation was not confirmed by the open-air combustions. Our results clearly show that the appearance of radial cracks is not diagnostic of the combustion of green wood. Nevertheless, the number of radial cracks (RC/cm²) could represent a new method that might help identifying the combustion of green wood in archaeological charcoal samples.     

Reburial of shipwrecks in marine sediments: a long-term study on wood degradation

Historical shipwrecks in marine environments are continuously decomposed by wood-degrading organisms, adapted to this specific environment. To protect the wrecks from degradation and to preserve the unique remains for future generations, reburial of wrecks using various covering materials has been suggested as a long-term preservation method. The following experiment was carried out to study the bio-protective effect of sediment. Sound oak, pine, and birch samples were buried above and within marine sediment in Marstrand harbour, and retrieved for analysis after 6, 12, 24, and 36 months. Macroscopic as well as light-microscopic examinations were carried out on each occasion. Marine borers (shipworm, Limnoria), soft rot and tunnelling bacteria were wood degraders immediately above the seabed; soft rot, tunnelling bacteria, and erosion bacteria were active 10 cm below the seabed; erosion bacteria were the only degraders at a depth of 43 cm below the seabed. The wood species had different durability towards the decay agents. After 3 years, wood samples above the seabed were totally decomposed, whereas wood was highly protected at 43 cm depth in sediment. In the sediment, decay decreased significantly with depth of burial. The results suggest that reburial of shipwrecks in marine sediment can be recommended as a simple and efficient method for long-term preservation of the wooden cultural heritage.     

Molecular history of tuberculosis from ancient mummies and skeletons

The origin and evolution of the infectious disease tuberculosis (TB) and its pathogens is still not fully understood. An important effort for a better understanding of the underlying mechanisms of TB evolution lies within the investigation of skeletal and mummified material dating back several thousand of years. In this work, molecular data from mummified and skeletal material from different time periods of the Old World are compared, and the current status of ancient mycobacterial DNA analysis in ancient human remains is discussed, with particular reference to the genetic evolution of human TB. The molecular analysis of material from southern Germany (1400–1800 AD), Hungary (600–1700 AD) and Egypt (3500–500 BC) revealed high frequencies of TB in all time periods. In several individuals from ancient Egypt the mycobacterial DNA could be further characterised by spoligotyping. Thereby, evidence for ancestral M. tuberculosis strains was found in the pre‐ to early dynastic material from Abydos (3500–2650 BC), while typical M. africanum signatures were detected in the Middle Kingdom tomb in Thebes‐West (2050–1650 BC). Samples from the New Kingdom to Late Period tombs (1500–500 BC) were characterised as modern M. tuberculosis strains. In concordance with other studies on ancient skeletal and mummified samples, no evidence for the presence of M. bovis was found. These results contradict the theory that M. tuberculosis evolved from M. bovis during domestication, but supports the new scenario that M. tuberculosis probably derived from an ancestral progenitor strain. Copyright © 2007 John Wiley & Sons, Ltd.     

Cats of the Pharaohs: Genetic Comparison of Egyptian Cat Mummies to their Feline Contemporaries

The ancient Egyptians mummified an abundance of cats during the Late Period (664 - 332 BC). The overlapping morphology and sizes of developing wildcats and domestic cats confounds the identity of mummified cat species. Genetic analyses should support mummy identification and was conducted on two long bones and a mandible of three cats that were mummified by the ancient Egyptians. The mummy DNA was extracted in a dedicated ancient DNA laboratory at the University of California - Davis, then directly sequencing between 246 and 402 bp of the mtDNA control region from each bone. When compared to a dataset of wildcats (Felis silvestris silvestris, F. s. tristrami, and F. chaus) as well as a previously published worldwide dataset of modern domestic cat samples, including Egypt, the DNA evidence suggests the three mummies represent common contemporary domestic cat mitotypes prevalent in modern Egypt and the Middle East. Divergence estimates date the origin of the mummies' mitotypes to between two and 7.5 thousand years prior to their mummification, likely prior to or during Egyptian Predyanstic and Early Dynastic Periods. These data are the first genetic evidence supporting that the ancient Egyptians used domesticated cats, F. s. catus, for votive mummies, and likely implies cats were domesticated prior to extensive mummification of cats.     

DNA analysis in charred grains of naked wheat from several archaeological sites in Spain

In the present work we attempt to recover endogenous ancient DNA from cereal grains preserved under different conditions: charred, partially charred and waterlogged. A total of 126 grains from naked wheat and 18 from barley from different sites on the Eastern Iberian Peninsula ranging from the beginning of agriculture in the region to the turn of the Common Era, were studied. Two different extraction protocols were used, a standard phenol–chloroform method and a silica-based DNA extraction procedure implemented for artificially charred seeds. Amplifications were directed to three markers: the large subunit of ribulose 1,5 biphosphate carboxylase (rbcL) and the microsatellite WCT12 in the chloroplast genome and the x and y subunits of the high molecular weight glutenin gene (Glu-1) in the nucleus. The first two were used to assess the preservation status of the samples, while with the third we tried to identify the wheat grains at species level. It was possible to obtain eleven positive amplifications in 8 partially charred seeds but only two amplifications of the Glu-1 gene from a single sample of the Early Bronze age were genome-specific. Different contamination sources were identified and reported. Cloning and alignment of sequenced clones showed a correspondence of the amplified fragment to modern wheat D genome haplotypes. This result suggests that the sample corresponds to hexaploid wheat (Triticum aestivum L.), thus being the first ancient DNA evidence to date for the cultivation of hexaploid wheat in the prehistoric agriculture of the Iberian Peninsula. Moreover, obtained results highlight contamination problems associated to the study of ancient archaeobotanical charred seeds suggest that the combination of a silica-based extraction method together with the amplification of specific targets is a good strategy for recovering endogenous ancient DNA from this kind of material.     

Low regional diversity of late cave bears mitochondrial DNA at the time of Chauvet Aurignacian paintings

The Chauvet-Pont d'Arc and Deux-Ouvertures caves, located along the Ardèche River (France), contain abundant remains of the extinct cave bear (Ursus spelaeus). Because they also display a variety of Palaeolithic anthropogenic evidences, such as the earliest charcoal drawings recorded to date (Chauvet-Pont d'Arc), and delicate engravings (Deux-Ouvertures), they offer the opportunity of studying the interaction between animals and human beings during a key period for Pleistocene species extinctions. We characterized cave bear specimens from these two sites by radiocarbon dating, stable isotopes, and mitochondrial DNA analysis. In Chauvet-Pont d'Arc, we obtained radiocarbon ages that ranged between 29,000 and 37,300 years before present (BP). The Deux-Ouvertures cave bear specimens clustered to the bottom of this time frame, returning radiocarbon ages of 27,440–30,220 years BP. Cave bear nitrogen isotope values were all compatible with a vegetarian diet. Mitochondrial DNA analysis, carried out on a highly variable domain of the control region, evidenced only two cave bear haplotypes, including a new haplotype, and a common one which largely predominated. We detected both haplotypes in Chauvet-Pont d'Arc, but only recorded the predominant one in the Deux-Ouvertures Cave. Our data put forward the surprising observation that cave bears inhabited Ardèche over a short period of time, from about 37,000 to 27,400 years BP. They were notably present during the first (Aurignacian) phase of human intrusions in Chauvet-Pont d'Arc, 30,000–32,000 years BP. This points to the possible competition for cave sites, presumably on a seasonal scale considering the cave bear habit for hibernation. During this time period, the small number of haplotypes is at variance with the extensive genetic diversity reported elsewhere for much more ancient specimens.     

The impact of traditional land use on woodlands: a case study in the Spanish Central System

We analyse the consequences of traditional use on forest characteristics during the last millennium in a mountain area of Spanish Central System, using information contained in documents, as well as cartography and toponymy. In the Middle Ages the local forests were transformed into municipal dehesas (communal fenced woods), communal wood pastures and arable lands. Pinewoods located in areas above 1500 m decreased because of the high grazing pressure. In the fifteenth century two manors were created (Buitrago and Montesclaros). Livestock became an important factor during this period. As a consequence an open wood was formed and oak coppices were also abundant (the felling of this species was at that time permitted by the Ordinances). At the end of the period of traditional management, pinewoods were disappearing and the main forest areas were located only in municipal dehesas. The area of beech was reduced in favour of melojo oak and scrub, due to the lower sprouting capacity of the beeches and their lower drought tolerance. Open wood pastures remain only in the eastern part of the study area, where there has been less intense human intervention. After the abolition of manors in the nineteenth century, arable land increased in the western part of the area, which had a higher population density. In the twentieth century, both human and livestock pressure decreased substantially and pine species were reintroduced by reforestation. The primitive savannah was transformed into ‘infilled savannah’, while temperate species spread around their refuges in municipal woods.     

Hemp in ancient rope and fabric from the Christmas Cave in Israel: talmudic background and DNA sequence identification

The “Christmas Cave”, a cave in the Qidron Valley near the Dead Sea and Qumran, has yielded a complex collection of plant-derived rope and fabric artifacts. Using polymerase chain reaction (PCR) to amplify DNA of the samples, we estimated the sizes and determined restriction patterns and base sequences of chloroplast genes, primarily rbcL (gene for the large subunit of ribulose bisphosphate carboxylase). DNA was successfully extracted from all samples, but was limited to sizes of approximately 200–300 base pairs. As expected, the DNA extracted from the samples was identified as coming primarily from flax (Linum usitatissamum L.), but two samples had a significant fraction, and all samples had at least a trace, of hemp (Cannabis sativa L.) DNA. Artifacts from the Christmas Cave were thought to date from Roman times, but it was thought possible that some could be much older. Accelerator mass spectrometry (AMS)-based ¹⁴C dating confirmed that the samples contained representatives from both the Roman and Chalcolithic periods. This paper provides a synthesis of DNA, isotope, and literary analysis to illuminate textile history at the Christmas Cave site.     

New trials in the consolidation of waterlogged archaeological wood with different acetone-carried products

Some acetone-carried consolidants for waterlogged archaeological wood were tested in order to evaluate treatments able to save time and energy. In details, colophony (rosin), two esterified colophonies (Rosin 100^® and Rosin 459^®), a mixture of colophony with PEG 3400 and a vinyl acetate - vinyl versate copolymer (Vinavil 8020S^®) were tested. The treatments were carried out at temperatures of 20 and 35 °C on waterlogged maritime pine, elm, oak and beech. The materials came from the archaeological site of the ancient ships of Pisa (Tuscany, Italy) and were dated back to VII cent. BC – II cent. AD. To evaluate the processes, equilibrium moisture content and dimensional stability of treated wood samples at different relative humidity, and retention of impregnating products were measured; moreover macroscopic and microscopic examination were also run to respectively assess the shape and appearance of treated wood and the way of deposition of consolidants. The results highlighted that natural and modified colophony treatments gave the most satisfactory results both in the maintenance of shape and dimensions of samples and in the stabilization with respect to RH variations. Moreover, the equilibrium moisture contents of samples treated with R100 and R459 were much reduced in comparison to the other consolidants and to untreated archaeological wood. This fact was related to the high retention values of those products that occluded most of the porosity including the microporosity of cell walls. Therefore, in terms of higroscopicity treated wood was more similar to impregnating substances rather than to decayed wood. This fact was considered helpful in contrasting the moisture-related negative effects in cases of eventual faults in the climate control during e.g. exhibition and in protecting treated wood from the risks of new fungal attacks.     

Mitochondrial DNA Analysis of Ancient Domestic Goats in the Southern Caucasus: A Preliminary Result from Neolithic Settlements at Göytepe and Hacı Elamxanlı Tepe

This study presents preliminary results of mitochondrial DNA analyses of modern and ancient domestic goats in the southern Caucasus in order to examine their phylogenetic relationship with modern and ancient goats. For this purpose, seven ancient samples were obtained from two early agricultural villages in west Azerbaijan (Göytepe and Hacı Elamxanlı tepe, dated to ca. 6000–5500 cal bc , the Pottery Neolithic period), in addition to five modern goat samples in the same region. In the study, mitochondrial DNA segments of the control region (216 bp for the Neolithic samples and 481 bp for the modern samples) were amplified, and phylogenetic analyses were performed using previously published reference DNA sequences. As a result, all the haplotypes found in this study were grouped in the haplogroup A of goats. The finding of the haplogroup A among domestic goats in the southern Caucasus in the early sixth millennium bc can be interpreted as part of the geographic expansion of this lineage from the areas of initial domestication to surrounding areas that include also South and Southeast Europe. In the southern Caucasus, the haplogroup A probably continued to be a major lineage among domestic goats since their emergence in this area to the present. In contrast, this lineage has not been detected among local wild goats including Capra aegagrus , indicating the external origin of domestic goats. This possibility is consistent with archaeological records that indicate sudden appearance of agricultural lifeways in the southern Caucasus and cultural connections with northern Mesopotamia. Copyright © 2016 John Wiley & Sons, Ltd.     

Preservation of fungi in archaeological charcoal

During the analysis of wood charcoal remains from archaeological sites, it is common to find different microorganisms and different forms of degradation present in the plant tissue. However, one may encounter difficulties when attempting to identify these microorganisms and determine when their attack occurred. This paper focuses on preservation aspects related to the microorganisms in wood and demonstrates the structural changes that take place in different types of decayed wood after it was converted into charcoal. The study seeks to determine whether the microbial attack found in archaeological woods took place before the burning of the wood or after. Burning experiments were conducted using wood that had been decayed by various types of fungi including white-rot, brown-rot, and soft-rot. The laboratory burnt wood samples showed decay patterns that were comparable to those observed in archaeological charcoal samples, indicating that signs of fungal infestation and features of decay can be preserved after burning with micromorphological details of mycelium and cell wall attack evident. This indication may provide important information related to the gathering of deadwood as fuelwood. In addition, examples of decayed wood preserved in archaeological charcoal assemblages are described. Their relationship to the archaeological context and environmental conditions may suggest different interpretative models concerning wood management strategies applied by past societies.     

考古木材降解评价的物理指标

为寻找一种能较为科学、方便地反映木材降解程度的指标,共收集不同地方出土的13种木材,8个树种,对这些树种的考古木材与新鲜木材的含水率、干缩性、基本密度、气干密度、综纤维素等指标进行对比分析。实验表明,基本密度和最大含水率(饱水含水率)基本上能够反映古木的降解程度,可以作为反映古木降解程度的物理评价指标。     

The use of the polymerase chain reaction (PCR) to detect Mycobacterium tuberculosis in ancient skeletons

The polymerase chain reaction has been used to extract ancient DNA from a wide range of different types of material. We have considered the possibility of finding residual bacterial DNA in bone that may have been infected with Mycobacterium tuberculosis using this technique. We propose a method of collecting samples and testing for the presence of degraded genetic material in ancient bone. The steps of the polymerase chain reaction are detailed and discussed, as are those for the preparation of the bone sample. Results obtained would suggest that this technique could have wide application in osteoarchaeological research by giving us new information on diseases of antiquity. Future avenues for the investigation of bacterial DNA in ancient bone are suggested.     

Short-chain n-alkanes (C16–20) in ancient soil are useful molecular markers for prehistoric biomass burning

The incorporation of plant biomass into soil usually leads to long-chain n-alkanes with a relative predominance of odd carbon numbered homologues. Contrastingly, an increase in short-chain even carbon numbered n-alkanes was found in charred biomass with progressing temperatures. We applied lipid analysis to buried ancient topsoils that contained charred organic matter and to corresponding control soils, which were characterized by a lighter color and lower contents of charred materials. Commonly, the proportion of lipid extracts was found to be lower in the ancient soil than in the control samples, which indicated an enhanced degradation of organic matter, e.g., by thermal degradation. All samples displayed a particular pattern of short-chain and even carbon numbered n-alkanes (maximum at n-C₁₆ or n-C₁₈). The ratios CPI (carbon preference index) and ACL (average chain length) for the investigated soil samples matched the ratios found for maize and rye straw charred at 400 °C or 500 °C, respectively. These molecular ratios indicate the presence of charred biomass. The predominance of short-chain and even carbon numbered n-alkanes was a result of thermal degradation of biomass. The degradation products were preserved in ancient soils and could be applied as molecular markers in archaeological or palaeoenvironmental research.