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Percussive technology is part of the behavioural suite of several fossil and living primates. Stone Age ancestors used lithic artefacts in pounding activities, which could have been most important in the earliest stages of stone working. This has relevant evolutionary implications, as other primates such as chimpanzees and some monkeys use stone hammer-and-anvil combinations to crack hard-shelled foodstuffs. Parallels between primate percussive technologies and early archaeological sites need to be further explored in order to assess the emergence of technological behaviour in our evolutionary line, and firmly establish bridges between Primatology and Archaeology. What are the anatomical, cognitive and ecological constraints of percussive technology? How common are percussive activities in the Stone Age and among living primates? What is their functional significance? How similar are archaeological percussive tools and those made by non-human primates? This issue of Phil. Trans. addresses some of these questions by presenting case studies with a wide chronological, geographical and disciplinary coverage. The studies presented here cover studies of Brazilian capuchins, captive chimpanzees and chimpanzees in the wild, research on the use of percussive technology among modern humans and recent hunter–gatherers in Australia, the Near East and Europe, and archaeological examples of this behaviour from a million years ago to the Holocene. In summary, the breadth and depth of research compiled here should make this issue of Philosophical Transactions of the Royal Society B, a landmark step forward towards a better understanding of percussive technology, a unique behaviour shared by some modern and fossil primates.  相似文献   

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The absence of Pan and Gorilla fossils from Africa has led some to suggest that African rain forests are not conducive to bone preservation. The absence of fossils is unfortunate as it hampers phylogenetic and socioecological interpretations on the divergence of the earliest hominids. For the most part, taphonomic studies have been restricted to cave and open country contexts. With this in mind, we have initiated a taphonomic project in a tropical rain forest, the Kibale Forest of western Uganda. In the course of bone gathering activities over the past 4 years, we have documented the retrieval of skeletal remains representing nine chimpanzees (Pan troglodytes schweinfurthii). Crania and mandibles are most commonly recovered, followed by elements of the axial skeleton, and finally, appendages. Vertical segregation of small compact bones can occur in areas with a soft substrate. Scavenging activity suggests the role of suids, but this has not been proven. Geochemical tests suggest that Kibale soils are neutral and may be conducive to bone preservation. Our independent preliminary data from bone weathering/survival experiments indicate that bones appear undamaged after several years and are able to accumulate on the forest floor. These results contrast with popular assumptions on the potential of African rain forests as potential fossil reservoirs.  相似文献   

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饶氏藻是我国绿藻门中的特有类群,藻体盘状.表面不平整。文中对中国各地的饶氏藻及泡状饶氏藻进行了广泛采集调查和显微结构观察,并比较了不同地区标本各层细胞的直径。还观察到许多地区的藻体表层细胞的特殊结构——突起,补充了该类群的显微结构特征。同时对河南修武云台山的泡状饶氏藻进行了电镜观察,与北京房山产的泡状饶氏藻比较,二者的超微结构特征十分相似。值得注意的是,这个种的线粒体超微结构很特殊,具有纵向排列的“嵴”。  相似文献   

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Summary The critical theory of evolution was developed by a group of scientists working together with Wolfgang F. Gutmann at the Senckenberg-Research-Institute in Frankfurt am Main. Gutmann worked at Senckenberg for 37 years. In this time he presented 247 contributions which are distributed over 47 periodicals and books. The ideas that were developed by Gutmann and his colleagues were innovative and pathbreaking for morphology and evolutionary biology. The large number of his morphological publications is indicative of the wide field that was opened up by the concepts of constructional morphology. As some of his colleagues have suggested, constructional morphology as an engineering approach to the study of organisms (i. e., engineering morphology) may replace the traditional concepts of morphology and anatomy and provides the observational base for the historical reconstruction of evolutionary pathways. Constructional morphology as a quasi-engineering approach can be the morphological pendant to the contemporary molecular approaches to biology, as it can provide the necessary morphological basis for the interpretation of the results of molecular studies in the light of evolution.  相似文献   

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通过对文献的研究,指出《中国植物志》和《Flora of China》中存在黔灵山冬青资料不完善的问题。结合实地跟踪考察及形态解剖,描述了黔灵山冬青雄、雌花,并绘制了形态图。雄花:二歧聚伞花序,单生于当年生枝条叶腋内,3~7朵,淡紫色;雌花:假二歧聚伞花序,单生于当年生枝条叶腋内,1~3朵,淡紫色或白色。完善了黔灵山冬青的分类学资料。  相似文献   

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Edith R. Saunders' contributions to floral anatomy are briefly considered. Fourteen of her abstracts and discussions and 49 of her lengthier works are cited. An index to 249 families of angiosperms sensu Airy Shaw (1973) keyed to Saunders' publications is given.  相似文献   

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The bovine J blood group substance exists as a glycosphingolipid (ceramide deca-hexoside as well as ceramide dodecahexoside) and as a glycoprotein. The lipidic form occurs in erythrocyte membranes, both forms are found in serum. The lipidic J substances were isolated from erythrocytes and from serum, and identified by thin-layer chromatography with lipidic J substances isolated from spleen. The glycoprotein nature of the non-lipidic J of serum was evident by pronase-catalysed hydrolysis yielding J-active glycopeptides of lower molecular weights. The lipidic J was completely extracted from lyophilized stroma with chloroform/methanol. From lyophilized serum, however. it was completely extracted only in the presence of water, indicating different binding partners in serum and in erythrocyte membranes. The J lipid was incorporated as intact molecule into the erythrocyte membrane by a simple incubation technique. The incorporation was inhibited by various glyc-erophospholipids (called blockers). The J glycoprotein could not be transferred to the erythrocyte membrane. Three methods are descrjbed which are suitable for the preparation of a blocker-free fraction enriched with J lipids from J-positive serum.  相似文献   

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Synopsis Eugenie Clark is an ichthyologist with a talent for communicating about marine life. Her life had three principal periods, (1) studies under Charles Breder, Carl Hubbs, Lester Aronson and Myron Gordon, (2) directorship of the Cape Haze Marine Laboratory sponsored by the Vanderbilts, and (3) professorship and inspired teaching at the University of Maryland. Genie proved that sharks have surprising learning abilities and that, contrary to popular opinion, none are vicious killers. During her studies on reproductive behavior, territoriality, and ecology of tropical marine sand-dwelling fishes of the Caribbean and Red seas, among many other phenomena, she discovered the cross-fertilizing hermaphroditeSerranus subligarius, the Moses and peacock soles producing toxins that repel sharks and other predators, and sharks sleeping in underwater caves in Mexico and Japan. She combined a love for swimming and diving with the study of marine fishes - from hard-hat diving and snorkeling to using SCUBA and submersibles. Professor emerita since 1992, she has ridden whale sharks and participated in dives using submersibles to 3 600 m depths. She is a recipient of over 25 honors and awards, participated in 24 television specials, and the current IMAX film on sharks. She is the author of theLady with a Spear andThe Lady and the Sharks which are of considerable popular fame.  相似文献   

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Physalins F and J are shown to be Physalin B 5β,6β-epoxide and 5α,6α-epoxide, respectively. The transformation of physalin F into physalin D (5,6-dihydro-5α,6β-dihydroxyphysalin B) and an acid-catalysed skeletal rearrangement of physalin F into isophysalin F are described.  相似文献   

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It is demonstrated that a new pulse sequence element, Spin-State-SelectiveCoherence Transfer (S3CT), via an intermediate state ofheteronuclear IS zero- or double-quantum coherence can transfer the twosingle-quantum coherences on one of the spins exclusively to any one of thetwo single-quantum coherences on the other spin. This fact is used for editinginto two subspectra that are most suitable for extraction of homo- orheteronuclear J coupling constants when S3CT is combined withhomonuclear coherence transfer during a mixing period. Experimentalconfirmation is obtained using a 15N-labeled 58-residue protein,the C-terminal Kunitz domain from human type VI collagen. The J coupling con-stants determined include 3JHN-H and3JN-H related to the and1 angles, respectively.  相似文献   

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The definition of relatively stable expressed internal reference genes is essential in both traditional blotting quantification and as a modern data quantitative strategy. Appropriate internal reference genes can accurately standardize the expression abundance of target genes to avoid serious experimental errors. In this study, the expression profiles of ten candidate genes, ACT1, ACT2, GAPDH, eIF1, eIF2, α-TUB, β-TUB, TBP, RNA Pol II and RP II, were calculated for a suitable reference gene selection in Paeonia ostii T. Hong et J. X. Zhang leaves under various drought stress conditions. Data were processed by the four regularly used evaluation software. A comprehensive analysis revealed that RNA Pol II was the most stable gene and eIF2 was the least stable one. In addition, the geNorm program provided the optimal choice of two reference gene combination, RNA Pol II and β-TUB, for qRT-PCR normalization in P. ostii subjected to different drought stress levels. Our research provided convenience for gene expression analysis in P. ostii under drought stress and promoted research of effective methods to alleviate P. ostii drought stress in the future.  相似文献   

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