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101.
Knapped stone tools constitute an interesting evidence of the mental abilities of their makers. Almost imperishable, they bear visible traces of the successive removals they come from, and of the flaking techniques used. On that basis, we present a few remarkable achievements along the evolution of prehistoric lithic technology, and discuss their capabilities. The tools of the oldest Palaeolithic already surpass the nut cracking from Chimpanzees. Some core reductions into flakes, as early as 2.3 My, show a repeated organization of the removals, and the capacity to prevent a problem. The regular and symmetrical hand-axes from Africa and Europe, appearing between 1 and 0.5 My, provide evidence of a mental template and hence a capacity of conceptualization. The Levalloisian core reduction, somewhat more recent, give evidence of a goal structured method: the technical actions were hierarchized and subordinate to morphological intentions.  相似文献   
102.
本文主要从生物因素方面考虑,分析了导致石质文物病害的主要原因和机理,并综述了国内外石质文物保护的现状、防治和修复方法。地衣是引起石质文物腐蚀的关键生物类群,与国外相比,目前国内专门针对地衣进行石质文物防治的研究鲜见报道。作者建议,石质文物的地衣生物腐蚀及防治研究应从以下方面入手:(1)石质文物地衣必须首先进行系统的种类调查;(2)对地衣腐蚀石质文物的机理进行深入研究;(3)探寻地衣病害安全有效的去除方法;(4)逐步探索地衣病害修复后的监测和预防方法。  相似文献   
103.
翟少冬 《人类学学报》2015,34(2):192-201
本文主要介绍了陶寺遗址石制品复制实验的目的、方法、过程和结果,其中,过程部分主要介绍了磨制石器的复制。结果部分主要是通过实验考察了陶寺遗址磨制石器生产所需的几种工艺,以及这些工艺的操作所需的工具、时间等因素。文章认为,陶寺遗址磨制石器的制作过程简单,一般只需打片和磨两个步骤。磨比较简单易操作,只是比较耗费时间;而打片相对于打制石器来讲,要简单很多。因此,陶寺遗址磨制石器的制作工艺总体来讲比较简单易操作。  相似文献   
104.
J. F. Parr 《Economic botany》2002,56(3):260-270
For Australian Aboriginal people plant resins have played an important role in both trade and the manufacture of hafted tools. In particular, the resins of theXanthorrhoea species were widely distributed and favored resources. The aim of this pilot study was to: (1) determine if starch grains were present in all of theXanthorrhoea resin samples examined, and (2) determine the feasibility of discriminating between resins of differentXanthorrhoea species by the morphological attributes of their starch grains. The results established that starch grains were present within all of theXanthorrhoea species resins that were examined. Moreover, for the purpose of identifying resins from within this genus the preliminary results suggest that starch grains have sufficient differences in attributes to allow discrimination between species. The results suggest that further research into the morphological attributes of starch grains in resins may prove to be an efficient and cost-effective means by which species identification could be achieved for small portions of archaeological resin samples.
Resumen  Las resinas de las plantas han tenido un papel muy importante para los Aborigenes Australianos en el intercambio y en la manofactura de herramientas con mangos. En particular, las resinas de las especiesXanthorrhoea eran recursos ampliamente distribuidos y preferidos. El objetivo de este estudio piloto fue: I) establecer si los granos de almidon estaban presentes en todas las muestras estudiadas de resina deXanthorrhoea y2) determinar la factibilidad de discriminacion entre las resinas de diferentes especies mediante los atributos morfológicos de sus granos de almidón. Los resultados establecieron que los granos de almidón se encontraban presentes en todas las especies de resinaXanthorrhoea examinadas. Ademas, para este proposito de identificar resinas desde dentro del genero glos resultados preliminares sugieren que los granos de almidón tienen suficientes diferencias en atributos para permitir la discriminación entre las especies. Los resultados indican que futuras investitigaciones dirigidas a las caracteristticas morfológicas de los granos de almidón en las resinas pueden ser un medio eficiente y barato a trovés del cual se puede lograr la indentificacion de especies.
  相似文献   
105.
Seedlings were grown in vitro from fertilized eggs and immature embryos of the Siberian stone pine. Cultivation of megagametophytes on a hormone-containing Murashige-Skoog medium from the egg formation until the globular embryo stage made it possible to manipulate fertilization and embryogenesis. Immature embryos are the most promising for in vitrocultivation. Their maturation and germination proceed within seven days of cultivation. When zygotic embryos were cultivated, adventitious buds were formed from cells at the cotyledon base and tips. When adventitious buds were subcultivated on a medium containing benzylaminopurine and naphthylacetic acid, organogenic callus and shoots were formed. Thus, cultivation of megagametophytes and embryos of the Siberian stone pine led to the completion of embryogenesis and formation of viable of seedlings.  相似文献   
106.
Nested polymerase chain reaction (PCR) assays were developed based on microsatellite regions for detection of Monilinia fructicola, the causal agent of brown rot of stone fruits, and Botryosphaeria dothidea, the causal agent of panicle and shoot blight of pistachio. The nested PCR primers specific to M. fructicola were developed based upon the sequence of a species‐specific DNA fragment amplified by microsatellite primer M13. The external and internal primer pairs EMfF + EMfR and IMfF + IMfR amplified a 571‐ and a 468‐bp fragment, respectively, from M. fructicola, but not from any other fungal species present in stone fruit orchards. The nested PCR primer pairs specific to B. dothidea were developed based upon the sequence of a species‐specific 1330‐bp DNA fragment amplified by microsatellite primer T3B. The external and internal primer pairs EBdF + EBdR and IBdF + IBdR amplified a 701‐ and a 627‐bp fragment, respectively, from B. dothidea, but not from any other fungal species associated with pistachio. The nested PCR assays were sensitive enough to detect the specific fragments in 1 fg of M. fructicola or B. dothidea DNA or in the DNA from only two conidia of M. fructicola or B. dothidea. The nested PCR assays could detect small numbers of M. fructicola conidia caught on spore‐trap tapes and detect visible infections of B. dothidea in pistachio tissues. Microsatellite regions with high numbers of copies are widely dispersed in eukaryotic genomes. The results of this study indicate that microsatellite regions could be useful in developing highly sensitive PCR detection systems for phytopathogenic fungi.  相似文献   
107.
福建三明船帆洞旧石器遗址   总被引:7,自引:4,他引:3  
船帆洞旧石器遗址可分为上、下两个文化层。在下文化层发现一处人工石铺地面遗存。出土石制品 30 0余件 ,同层出土的哺乳动物化石包括巨貘、中国犀和鬣狗 3个绝灭种 ,其年代应属旧石器时代晚期。上文化层出土物以打制石器与磨制骨、角器共存为主要文化特征 ,其时代应晚于下文化层 ,可能仍属旧石器时代。  相似文献   
108.
保鲜剂对夏季香石竹切花衰老的延缓作用   总被引:10,自引:0,他引:10  
石贵玉  周巧劲  伍永炎  陈宁承   《广西植物》1994,14(4):341-344
香石竹切花瓶插期间花瓣中SOD和蛋白质在前期上升,然后比处理组提前3天呈下降趋势。采后花瓣中CAT、可溶性总糖和蔗糖均为下降。经由蔗糖、8-羟基喹啉和植物生长调节剂或钴镍盐组成的保鲜剂能延缓切花花瓣中SOD、CAT活性的下降,阻碍蛋白质、可溶性总糖和蔗糖的降解速度,同时使切花的瓶插寿命延长、含水量增加。  相似文献   
109.
110.
楼房子遗址系陇东地区一处旧石器时代中期的旷野遗址。2018年对楼房子遗址下文化层下部(第14、15层)进行了发掘,发掘面积为16 m2,出土大量石制品、动物化石。石制品原料以石英砂岩和硅质灰岩为主,类型包括石核、石片、石器、断块或断片、备料等。剥片采用硬锤锤击法,石器修理以硬锤锤击法为主。石制品类型和技术总体上属于北方小石器传统。结合地层堆积及相关的孢粉分析初步认为,楼房子遗址下文化层时代与MIS5相当。  相似文献   
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