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1.
We explore the diachronic development of verbal reduplication in Ancient Egyptian (Afro-Asiatic) by systematically comparing reduplicative stem formations in Old Egyptian (2500–2000 BC) and in Coptic Egyptian (3rd–12th c. AD). Old Egyptian is a language with a rich inventory of reduplication patterns, which have been reduced in the course of almost four thousand years of uninterrupted language history. Coptic retains only a limited number of reduplicative stem formations, frequently with concomitant loss of the simple stem. We show that the decreasing productivity of verbal reduplication in the language correlates with broad morphological and syntactic changes in the verbal domain.  相似文献   

2.
The population history of the East Slavs is complicated. There are still many unanswered questions relating to the origins and formation of the East Slavic gene pool. The aims of the current study were as follows: (1) to assess the degree of biological affinity in medieval East Slavic tribes and to test the hypothesis that East Slavic peoples have a common origin; (2) to show their genetic connections to the autochthonous populations of the northern part of Eastern Europe (Baltic and Finno‐Ugric tribes); and (3) to identify a genetic continuity between the bearers of Chernyakhov culture and medieval Eastern Slavs. In this study, nonmetric cranial trait data for medieval East Slavic tribes and comparative samples from unrelated groups were examined. Analyzes of phenotypic differentiation were based on Nei's standard genetic distance and hierarchical GST statistics. The results obtained suggest that the genetic affinity of the East Slavic tribes is due not only to inter‐tribal gene flow, but is, more importantly, a result of their common population history. Evidence of gene flow from the Baltic and Finno‐Ugric groups was showed in the gene pool of Eastern Slavs, as was genetic continuity between medieval East Slavic tribes and the populations of the preceding Chernyakhov culture. These findings support a “generalizing” hypothesis of East Slavic origin, in which a Slavic community was formed in some particular ancestral area, and subsequently spread throughout Eastern Europe. Am J Phys Anthropol 152:495–505, 2013. © 2013 Wiley Periodicals, Inc.  相似文献   

3.
Ribosomal proteins and colorectal cancer   总被引:1,自引:0,他引:1  
Lai MD  Xu J 《Current Genomics》2007,8(1):43-49
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4.
In this article, I shall discuss the treatment of reduplication, and most notably total reduplication in an implemented grammar of Hausa. I shall compare several patterns observed in the language and conclude, on the basis of segmental and suprasegmental properties alike, that partial and total reduplication operate on entirely different structures: phonological representations of limited size (max: CVC) in the case of partial reduplication, and morphological representations, such as stems in the case of total reduplication. Finally, I shall show that partial reduplication can readily be captured by the morphophonological means offered by the underlying formalism, yet argue that total reduplication is best modelled on the basis of a binary morphological construction. I shall propose a formalisation that keeps all of the linguistic generalisations within the grammar proper, yet ensures compositionality and reversibility.  相似文献   

5.
6.
The structure and diversity of mitochondrial DNA (mtDNA) macrohaplogroup U lineages in Russians from Eastern Europe are studied on the basis of analysis of variation of nucleotide sequences of complete mitochondrial genomes. In total, 132 mitochondrial genomes belonging to haplogroups U1, U2e, U3, U4, U5, U7, U8a, and K are characterized. Results of phylogeographic analysis show that the mitochondrial gene pool of Russians contains mtDNA haplotypes belonging to subhaplogroups that are characteristic only of Russians and other Eastern Slavs (13.7%), Slavs in general (11.4%), Slavs and Germans (17.4%), and Slavs, Germans, and Baltic Finns (9.8%). Results of molecular dating show that ages of mtDNA subhaplogroups to which Russian mtDNA haplotypes belong vary in a wide range, from 600 to 17000 years. However, molecular dating results for Slavic and Slavic-Germanic mtDNA subhaplogroups demonstrate that their formation mainly occurred in the Bronze and Iron Ages (1000–5000 years ago). Only some instances (for subhaplogroups U5b1a1 and U5b1e1a) are characterized by a good agreement between molecular dating results and the chronology of Slavic ethnic history based on historical and archaeological data.  相似文献   

7.
Larry M. Hyman 《Morphology》2009,19(2):177-206
In this study I present a comparative and historical analysis of “frequentative” Bantu verb-stem reduplication, many of whose variants have been described for a number of Eastern and Southern Bantu languages. While some languages have full-stem compounding, where the stem consists of the verb root plus any and all suffixes, others restrict the reduplicant to two syllables. Two questions are addressed: (i) What was the original nature of reduplication in Proto-Bantu? (ii) What diachronic processes have led to the observed variation? I first consider evidence that the frequentative began as full-stem reduplication, which then became restricted either morphologically (by excluding inflectional and ultimately derivational suffixes) and/or phonologically (by imposing a bisyllabic maximum size constraint). I then turn to the opposite hypothesis and consider evidence and motivations for a conflicting tendency to rebuild full-stem reduplication from the partial reduplicant. I end by attempting to explain why the partial reduplicant is almost always preposed to the fuller base.  相似文献   

8.
9.
Ribosomes are highly conserved macromolecular machines that are responsible for protein synthesis in all living organisms. Work published in the past year has shown that changes to the ribosome core can affect the mechanism of translation initiation that is favored in the cell, which potentially leads to specific changes in the relative efficiencies with which different proteins are made. Here, I examine recent data from expression and proteomic studies that suggest that cells make slightly different ribosomes under different growth conditions, and discuss genetic evidence that such differences are functional. In particular, I argue that eukaryotic cells probably produce ribosomes that lack one or more core ribosomal proteins (RPs) under some conditions, and that core RPs contribute differentially to translation of distinct subpopulations of mRNAs.  相似文献   

10.
Neocortical state variables are defined and evaluated at three levels: microscopic using multiple spike activity (MSA), mesoscopic using local field potentials (LFP) and electrocorticograms (ECoG), and macroscopic using electroencephalograms (EEG) and brain imaging. Transactions between levels occur in all areas of cortex, upwardly by integration (abstraction, generalization) and downwardly by differentiation (speciation). The levels are joined by circular causality: microscopic activity upwardly creates mesoscopic order parameters, which downwardly constrain the microscopic activity that creates them. Integration dominates in sensory cortices. Microscopic activity evoked by receptor input in sensation induces emergence of mesoscopic activity in perception, followed by integration of perceptual activity into macroscopic activity in concept formation. The reverse process dominates in motor cortices, where the macroscopic activity embodying the concepts supports predictions of future states as goals. These macroscopic states are conceived to order mesoscopic activity in patterns that constitute plans for actions to achieve the goals. These planning patterns are conceived to provide frames in which the microscopic activity evolves in trajectories that adapted to the immediate environmental conditions detected by new stimuli. This circular sequence forms the action-perception cycle. Its upward limb is understood through correlation of sensory cortical activity with behavior. Now brain-machine interfaces (BMI) offer a means to understand the downward sequence through correlation of behavior with motor cortical activity, beginning with macroscopic goal states and concluding with recording of microscopic MSA trajectories that operate neuroprostheses. Part 1 develops a hypothesis that describes qualitatively the neurodynamics that supports the action-perception cycle and derivative reflex arc. Part 2 describes episodic, “cinematographic” spatial pattern formation and predicts some properties of the macroscopic and mesoscopic frames by which the embedded trajectories of the microscopic activity of cortical sensorimotor neurons might be organized and controlled. URL: http://sulcus.berkeley.edu  相似文献   

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Agroinfiltrated Nicotiana benthamiana is a flexible and scalable platform for recombinant protein (RP) production, but its great potential is hampered by plant proteases that degrade RPs. Here, we tested 29 candidate protease inhibitors (PIs) in agroinfiltrated N. benthamiana leaves for enhancing accumulation of three unrelated RPs: glycoenzyme α‐Galactosidase; glycohormone erythropoietin (EPO); and IgG antibody VRC01. Of the previously described PIs enhancing RP accumulation, we found only cystatin SlCYS8 to be effective. We identified three additional new, unrelated PIs that enhance RP accumulation: N. benthamiana NbPR4, NbPot1 and human HsTIMP, which have been reported to inhibit cysteine, serine and metalloproteases, respectively. Remarkably, accumulation of all three RPs is enhanced by each PI similarly, suggesting that the mechanism of degradation of unrelated RPs follows a common pathway. Inhibitory functions HsTIMP and SlCYS8 are required to enhance RP accumulation, suggesting that their target proteases may degrade RPs. Different PIs additively enhance RP accumulation, but the effect of each PI is dose‐dependent. Activity‐based protein profiling (ABPP) revealed that the activities of papain‐like Cys proteases (PLCPs), Ser hydrolases (SHs) or vacuolar processing enzymes (VPEs) in leaves are unaffected upon expression of the new PIs, whereas SlCYS8 expression specifically suppresses PLCP activity only. Quantitative proteomics indicates that the three new PIs affect agroinfiltrated tissues similarly and that they all increase immune responses. NbPR4, NbPot1 and HsTIMP can be used to study plant proteases and improve RP accumulation in molecular farming.  相似文献   

13.
Micromorphological characters of leaf epidermis of 27 published species of Chimonobambusa Makino were examined by both light and scanning electron microscopes (Table 1). On the adaxial surface, bulliform cells are of irregular or tetragonal shape and in 2-- 3 rows between veins; stomata rare. On the abaxial surface, intercostal long cells are of thin and sinuous wall; short cells solitary, paired, or 3 to several in a row on veins; silica bodies narrow tall or saddle like; bicellular hairs common, with the basal cell slightly longer than or as long as the distal cell; hooks elliptic and apiculate, common in some species and rare in the others; papillae numerous, those overarching stomata showing different patterns (Plates 1, 2). The examined species exhibit three types of leaf epidermis (Table 2 ): 1, papillae widely spread, 4 rod- like papillae overarching the individual stomata, hooks common, including all the six examined species of Sect. Qiongzhuea and 9 species of Sect. Oreocalamus; 2, papillae around stomata only (with the exception of C. microfloscula), the 4 papillae branched or curved, plus several small ones, forming an arciform cover over the individual stomata, hooks sparse, including 7 species of Sect. Oreocalamus and 1 species of Sect. Chimonobambusa; 3, papillae overarching stomata intermediate between the other two types, with the other characters similar to type 1, including 2 species of Sect. Chimonobambusa and 2 species of Sect. Oreocalamus. The three types more or less correspond to the current classification of the genus based on gross morphology, but since Sect. Oreocalamus showed all the three types and type 3 was somewhat intermediate between the other two, present data support a broad sense of the genus Chimonobambusa, and the three sections proposed by Ohrnberger (1990) are to some extent acceptable. The results support the removing of C. luzhiensis from Sect. Qiongzhuea, but reassignment of C. metuoensis to Sect. Qiongzhuea cannot be confirmed. In addition, the leaf epidermis is of diagnostic value at species level. The data support the inclusion of C. linearifolia in C. angustifolia, but do not support that of C. rivularis in C. lactistriata, nor of C. yunnanensis and C. tuberculata in C. armata (Ohrnberger, 1990). In fact, C. yunnanensis, C. tuberculata and C. lactistriata, in addition to C. hirtinoda, are similar to C. qudrangularis in both leaf and gross morphological characters; so is C. pachystachys to C. utilis, C. neopurpurea to C. marmorea, and maybe C. rigidula to C. szechuanensis. They are possibly sister-species.or even conspecific, respectively. The various specific papillate patterns are characteristic of bamboo taxa, andinvestigation of wider samples will be of great interest in bamboo systematics.  相似文献   

14.
槭树科花粉形态及其系统学意义   总被引:9,自引:1,他引:9  
报道了槭树科(Aceraceae)槭属21组33种和金钱槭属2种植物的花粉形态。本科花粉近球形至长球形,极面观为三裂圆形。从花粉萌发孔类型看,金钱槭属Dipteronia具三孔沟,槭属(Acer)除4组具三孔沟外,其余均为三沟。从花粉外壁纹饰看,金钱槭属2个种和槭属的大多数种为条纹状,罕为细条纹-拟网状和皱波状。通过花粉形态分析,并结合其它方向的证据,我们认为:(1)Sect.Palmata,Sect.Spicata和Sect.Microcarpa可能是槭属中与金钱槭属关系最密切的类群;(2)A.distalum和A.nipponicum代表了近缘的两个单种组;(3)A.pseudoplatanus不同于Sect.Acer的其它4个种而与A.saccharum可能存在更为密切的关系;(4)Sect.Carpinifolia(细条纹-拟网状外壁纹饰)和Sect.Negundo(皱波状外壁纹饰)则可能代表了槭属中最特化的类群;(5)按槭树科花粉三孔沟到三沟的演化规律,Dipteronia较Acer原始。  相似文献   

15.
Study on the primary structure of more than 100 regulatory peptides was carried out with the view of determining their structural similarity. Practically all regulatory peptides appeared to be related to each other. One regulatory peptide can bear similarity to several regulatory peptides (RPs) which is realized by different fragments. The structural similarity of RPs was in some cases unexpected, e. g., somatocrinin-thymosin, secretin-endorphin, etc. Gastro-intestinal peptides were related to most RPs. It seems likely that these peptides are the most ancient ones among RPs.  相似文献   

16.
Mussels (Mytilus sp.) from two regions along the permanent salinity gradient within the Baltic proper were exposed to copper (35 ppb) or petrol (0.3 mL/L) for 10 days and analyzed for mRNA expressions in gill tissue. Expression of mRNAs for the heat shock proteins HSP70 and HSP90 was significantly induced by copper, but not by petrol. For the metallothioneins MT10 and MT20, regional differences in mRNA expressions could be seen. In mussels from the northern Baltic proper, MT20 expression increased 2.8 and 3.4 times, after exposure to copper and petrol, respectively. In contrast, no change could be seen in MT20 expression for mussels from the southern Baltic proper. MT10 showed a peculiar expression not previously described. For some mussels, no expression at all was detected, some showed a weak expression and for some individuals a strong expression could be seen. For the mussels from the southern Baltic proper, the number of individuals with a strong expression of MT10 increased from 1 out of 18 (control), to 7 and 8, after exposure to copper and petrol, respectively. The results clearly show that responses vary between different regions within the Baltic proper, which emphasises the importance to study interactions between contaminants, populations and regions.  相似文献   

17.
栝楼属花粉形态研究及其在分类学上的意义   总被引:5,自引:0,他引:5  
本文收集了国内外栝楼属Trichosanthes 31种1变种,在光学显微镜和扫描电镜下,进行了花粉粒形态的比较观察。该属花粉粒为3孔沟型,外壁表面纹饰可分为四个类型,即:疣状或皱波状(小苞组),粗网状(大苞组),细网状或光滑(叶苞组),近光滑或皱波状(王瓜组)。这四个类型的划分与植物形态分类基本一致,可作为分组及分种的依据之一。花粉特征支持将叶苞组分为叶苞亚组和柔毛亚组,如叶苞亚组有明显的沟,而柔毛亚组没有。  相似文献   

18.
19.
Objectives: The paper was aimed to establish the influence of some general and local factors on adaptation process to removable prostheses (RPs). The adaptation process is a complex issue, which is often associated with painful reactions. Those complaints force patients to visit a dentist who makes alterations to reduce the patient's discomfort. Material and methods: The study involved analysis of 300 dental records of patients who visited our Department for RPs. The authors analysed the influence of gender, age, condition of general health, maintenance of the prosthetic base tissues and the kind of prostheses on the process of adaptation. It was measured by means of a number of follow‐up visits of the patients to our polyclinic. The findings were analysed statistically by means of chi‐squared test. The level of significance was assumed to be p < 0.05. Results and conclusions: Adaptation to RPs without any correction was revealed by about one‐fifth of patients. Men adapted to RPs better than women. The biggest problems with adaptation to RPs were observed in patients using a complete and partial prosthesis simultaneously. The number of follow‐up visits by patients who were treated with RPs for the first time or had been treated before was almost the same. Adaptation of RPs on an atrophic muco‐osseous ridge was associated with more multiple visits than in the case of a well‐preserved ridge. Healthy patients adapt to RPs better than patients with systemic disorders. Taking into account the limitations of the study, the number of follow‐up visits may be used as a helpful indicator of the adaptation process.  相似文献   

20.
Fruit features of 17 Acaena species in New Zealand were investigated to determine the relations between reproductive allocation patterns, mode of dispersal and species ecology. Three basic morphological types, corresponding to major sections within the genus, are represented: spineless fruits (Sect. Pteracaena—one species), spined fruits lacking barbs (Sect. Microphyllae—6 species), and spined fruits with barbs (Sect. Ancistrum—10 species). The presence of terminal barbs on spines enhances fruit adhesion to animals, and is associated with the development of longer scapes, globular many-fruited capitula, and smaller single-seeded fruits. Barb-spined species generally have the broadest geographical range and habitat distribution within New Zealand, and are the only species of Acaena to occur in forests or on offshore islands. These species are generally strongly stoloniferous. Acaena species with barbless spines and/or no spines are often regional endemics confined to open and/or localised habitats, are rhizomatous, and may be dispersed by water, ingestion or wind. There is a tight correlation between intrageneric classification and species ecology and fruit features which requires testing via independent phylogenetic analysis based on molecular genetic characters. Although avian dispersers have declined since human settlement, introduced mammals may be performing a similar function for barbed Acaena species.  相似文献   

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