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21.
    
Anatomically preserved mature stems of late Middle Triassic corystosperms from the Paramillo Formation of Argentina are described and assigned to Cuneumxylon spallettii gen. nov. et sp. nov. The silicified specimens show features of the pith, primary xylem and successive rings of secondary xylem and phloem. The most striking characteristic is the anomalous secondary growth, represented by secondary xylem bounded by arcs of secondary phloem probably derived from successive repositioned cambia. Cuneumxylon has two kinds of unusual centrifugal secondary growth. The first shows unequal activity of different portions of the cambium on the circumference of the axes; the consequent restriction of cambial activity to certain restricted areas develops wedged stems, which often split. The second produces polyxylic stems following supernumerary cambial activity. As in extant plants growing in arid regions, the included phloem and the associated parenchyma may have had functional value avoiding desiccation of the outer tissues of the stem during droughts. Anatomical features of other Corystospermaceae were used to determine systematic affinities and to establish relationships among medullosans, corystosperms and cycads.  相似文献   
22.
    
ABSTRACT

This paper proposes a classification of the risks threatening archaeological sites in southern Iraq and suggests some possible remediation to better preserve them. This has been possible thanks to a research methodology that combines remote sensing and ground control on a sample of 558 sites documented by the Iraqi-Italian QADIS survey project. A three-tier typological framework has been created illustrating the risks jeopardising the cultural heritage of the region. This research showed that the most impacting risks are the ones caused by agricultural activity, despite current narratives which mainly focus on looting and violent destruction. To get at the root of the problem, current laws protecting cultural heritage in Iraq are analysed, as well as how the cultural authorities are organised on the ground. Improving the organisation of the SBAH, engaging the local communities towards the issue of sites’ protection and introducing preventive archaeology are among the solutions proposed.  相似文献   
23.
    
Balts' territories have one peculiarity—large amounts of horse bones are found in burial grounds. This phenomenon is typical to the Prussians (5th–11th centuries) and Lithuanians (Kaunas region 8th–11th centuries) Horse burials of the 8th–11th centuries reflect the archaeological culture of Middle Lithuania most significantly. Several horse burial types have been defined on the basis of individuals; osteological signs and the archaeological data of the horse remains. A typical horse grave is when the whole horse was buried. Sometimes only a head or a head with forelegs, or scattered horse remains are found in a burial. The large number of burial grounds with an abundance of horse graves testifies to a very expressive ritual of horse offering in the Balts' region. On the basis of the data obtained, we determined that mostly 4–10 year old horses were buried in the grounds of Middle Lithuania. From the bone measurements, it has been determined that the length of metacarpals ranges between 180 and 216 mm (the average length 193.1±0.99 mm); the length of metatarsals between 218 and 253 mm (average length 233.9±0.73 mm).These data demonstrate that horses of different types were buried in Marvelė and Veršvai burial grounds (wither height 120–136 cm). A certain number of the larger horses (wither height 136–144 and 153 cm; length of metacarpals 210–222 mm) might not have belonged to local breeds. We have come to the conclusion that the most similar horse skeletons (according to the osteometric data) were found in Latvia. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
24.
    
Abstract

During dredging works for the new London Gateway Port in 2011, fragments of a German Ju 88 bomber were recovered from the Thames Estuary. Subsequent archaeological investigation by Wessex Archaeology, using geophysical survey and divers, resulted in the location of the wreck site and its subsequent recovery under licence in 2012. Post-recovery analysis has enabled it to be identified as a very rare prototype Ju 88T. The aircraft, flown by men of the secretive Luftwaffe special operations unit VOdL, was lost during a reconnaissance mission to record bomb damage at Chelmsford in 1943. The Norwegian fighter ace who shot it down, Marius Eriksen, subsequently achieved fame as a Norwegian skiing champion and actor. The recovery was unusual in that it was carried out as a staged archaeological investigation and in the context of offshore development, where ‘avoidance’ is the usual strategy.  相似文献   
25.
This paper tests the validity of the circumference at the nutrient foramen of the tibia for sex determination on two human osteological collections: the Lisbon Collection of Identified Skeletons (n = 160) and the São Martinho medieval archaeological collection from Leiria, Portugal (n = 57). The methodological approach chosen to conduct the test was the sectioning point method. The overall accuracy (males and females combined) in the Lisbon Collection was 78% and in the São Martinho Collection it reached 90%. In both series, females were more accurately classified than males. This paper advocates the importance of developing and using sample specific methods for sex determination in modern and in archaeological human osteological assemblages. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
26.
氯离子选择性电极测定铁器碱性脱盐溶液中氯离子的含量   总被引:2,自引:1,他引:1  
在铁质文物的保护过程中,脱盐是重要的保护程序之一。通常铁器的脱盐溶液为碱性。本工作主要研究氯离子选择性电极法在测定碱性脱盐溶液中的氯离子含量时,溶液pH值和复配溶液中的表面活性剂对测定结果的影响。实验结果表明:(1)用氯离子选择性电极法测定碱性脱盐溶液或复配碱性脱盐溶液中的氯离子浓度是可行的;(2)溶液的pH值对测量结果有一定的影响,当溶液pH值在2~7范围内时,其对电位值影响不大;(3)表面活性剂对测量结果影响较小,在实际应用中,应配制与待测溶液组分相同的氯离子标准溶液,后期数据处理并绘制标准曲线,以使测量结果尽可能接近实际值。精密度和回收率实验表明,该方法准确度满足定量分析的要求。由此可见,当脱盐溶液为碱性NaOH或复配碱性NaOH溶液时,用氯离子选择性电极实时监测脱盐溶液中的氯离子含量能较好地反映器物脱盐程度。  相似文献   
27.
The soluble and exchangeable ions for a soil profile from the Roonka archaeological site. Lower Murray Basin, South Australia, are compared with the total elemental content of the soils. Since the chemical composition of post-mortem ionic substitution phases and secondary minerals in archaeological bone will depend on the availability of ions to the soil solution under field conditions, it is suggested that models addressing diagenesis in bone employ soluble and exchangeable ions rather than total elemental soil data.  相似文献   
28.
    
Micromammalian bone assemblages from modern pellets of the strigiform Bubo virginianus magellanicus, from the upper Atuel River (southern Mendoza, Argentina), were taphonomically analysed. The results allow us to place B. v. magellanicus in the category of intermediate modification (Category 2). This sample has also been compared with results from other members of this genus, in order to classify B. v. magellanicus as a taphonomic agent. The participation of the Bubo species in archaeological accumulations has been documented, but in Argentina, the role of B. v. magellanicus has been reported up to the present. It is partly because of the sequence of one archaeological site in the south of Mendoza Province called Laguna El Sosneado‐3 (LS‐3). However, considering the absence of a current taphonomic model of this owl, this participation was mentioned as a hypothesis. In the current investigation, archaeological and modern samples have been compared. The results indicate that the skeletal element assemblages recovered from LS‐3 were accumulated by strigiform birds. Taphonomical evidence of light modifications on units I and IV indicates that Tyto alba (Category 1) was probably the main species involved in these units, whereas the taphonomical evidence on skeletal element assemblages recovered from units II and III suggests the action of a strigiform with a major category of modification such as B. v. magellanicus. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
29.
    
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30.
This paper refers to the body of international, national and regional legislation that exists to protect submerged cultural heritage sites. It advocates the use of the consultation process available through current legislation to protect submerged sites through preservation or through record by archaeological mitigation. It reviews the main types of commercial seabed developments and opens discussion on the appropriate archaeological response.  相似文献   
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