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31.
Random amplification of polymorphic DNA (RAPD) was conducted by using 10 random primers (P-1 to P-10) inGracilaria lemaneiformis. Phase and sex specific bands were amplified by primers P-2, P-6, P-7 and P-8: for P-2 a 1.4 kb band was found in female gametophytes and tetrasporophytes, for P-6, a 0.6 kb band appeared in male gametophytes and tetrasporophytes; for P-7, a 0.76 kb band appeared in male gametophytes and tetrasporophytes; for P-7, a 0.72 kb band appeared in female gametophytes and tetrasporophytes; for P-8, a 0.73 kb band only appeared in male gametophytes.
相似文献32.
长白山望天鹅火山双峰式火山岩的成因演化 总被引:12,自引:7,他引:5
望天鹅火山活动从早到晚分为三期:①长白期以粗面玄武岩为主,少量碱性玄武岩和玄武质粗安岩;②望天鹅期又分早晚两个亚期,早期玄武质粗安岩和粗面岩,晚期碱性流纹岩;③红头山期碱性流纹岩。望天鹅火山岩的岩石学、REE、不相容元素和Nd、Sr、Pb同位素(143Nd/144Nd、87Sr/86Sr、206Pb/204Pb分别变化于0.512567~0.512642、0.705198~0.716742和17.434~17.934),揭示了岩浆源区明显受洋壳的俯冲和壳幔混合混染,三期火山岩具有共同的岩浆源区和紧密的成因演化关系,分离结晶作用控制了岩浆的演化过程。原始碱性系列玄武质岩浆经橄榄石、辉石的结晶分异,向粗面玄武岩演化;粗面玄武岩经斜长石强烈的结晶分离作用,还有辉石、钛铁氧化物和磷灰石的分离结晶作用形成具显著Eu、Sr、Ba、Ti、P负异常的碱性流纹岩,导致本区火山岩缺失中性(SiO2=57%~63%)的安山岩和粗安岩,呈现双峰式火山岩组合的特点。 相似文献
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Gracilariopsis lemaneiformis is a commercially exploited alga. Its filaceous thallus can be divided into three parts, holdfast, middle segment and tip. The growth and branch forming trend and agar content of these three parts were analyzed, respectively, in this study. The results showed that the tip had the highest growth rate and branched most, although it was the last part with branch forming ability. The holdfast formed branches earliest but slowly. Holdfast had the highest agar content. We also assessed the difference in protoplast formation and regeneration among three parts. The middle segment displayed the shortest enzymolysis time and the highest protoplast yield; whereas the tip had the strongest vitality of protoplasts formation. Juvenile plants were only obtained from the protoplasts generated from the tip. These results suggested that the differentiation and function of G. lemaneiformis was different. 相似文献
37.
Bingwen Qiu Canying Zeng Chongcheng Cheng Zhenghong Tang Jianyang Gao Yinpo Sui 《中国地理科学(英文版)》2014,24(3):317-327
Most evaluation of the consistency of multisensor images have focused on Normalized Difference Vegetation Index (NDVI) products for natural landscapes, often neglecting less vegetated urban landscapes. This gap has been filled through quantifying and evaluating spatial heterogeneity of urban and natural landscapes from QuickBird, Satellite pour l'observation de la Terre (SPOT), Ad- vanced Spacebome Thermal Emission and Reflection Radiometer (ASTER) and Landsat Thematic Mapper (TM) images with variogram analysis. Instead of a logarithmic relationship with pixel size observed in the corresponding aggregated images, the spatial variability decayed and the spatial structures decomposed more slowly and complexly with spatial resolution for real multisensor im- ages. As the spatial resolution increased, the proportion of spatial variability of the smaller spatial structure decreased quickly and only a larger spatial structure was observed at very coarse scales. Compared with visible band, greater spatial variability was observed in near infrared band for both densely and less densely vegetated landscapes. The influence of image size on spatial heterogeneity was highly dependent on whether the empirical sernivariogram reached its sill within the original image size. When the empirical semivariogram did not reach its sill at the original observation scale, spatial variability and mean characteristic length scale would increase with image size; otherwise they might decrease. This study could provide new insights into the knowledge of spatial heterogeneity in real multisen- sor images with consideration of their nominal spatial resolution, image size and spectral bands. 相似文献
38.
We investigate the quasi‐static simple shear flow of a two‐dimensional assembly of cohesionless particles using discrete element method (DEM) simulations. We focus on the unsteady flow regime where the solid would experience significant evolution of stresses, mobilised shear strength and dilation. We construct the DEM model using a discretised‐wall confined granular cell where the apparent boundary is allowed to dilate or contract synchronously with the confined solid. A rather uniform simple shear field is achieved across the whole assembly, which benefits rheological studies in generalising constitutive laws for continuum methods. We examine two aspects of the simple shear behaviour: macroscopic stress and strain rate evolution, particularly the non‐coaxiality between the principal directions of the two; and micromechanics such as evolution of fabric. For an initially anisotropic specimen sheared under constant normal pressure, the direction of principal stress rotates towards that of the principal strain rate, gradually reducing the degree of non‐coaxiality from about 45° to fluctuating around 0°. The rate in approaching coaxiality is slower in samples with larger initial porosity, stress ratio and mean stress. Generally, a faster rate in approaching coaxiality in simple shear is observed in a more dilatant sample, which often shows a larger degree of mobilised fabric anisotropy, suggesting the possible important role of instantaneous internal friction angle. The evolution of principal fabric direction resembles that of the principal stress direction. © 2013 The Authors. International Journal for Numerical and Analytical Methods in Geomechanics published by John Wiley & Sons, Ltd. 相似文献
39.
Multi‐scale investigations aided by the discrete element method (DEM) play a vital role for current state‐of‐the‐art research on the elementary behaviour of granular materials. Similar to laboratory tests, there are three important aspects to be considered carefully, which are the proper stress/strain definition and measurement, the application of target loading paths and the designed experiment setup, to be addressed in the present paper. Considering the volume sensitive characteristics of granular materials, in the proposed technique, the deformation of the tested specimen is controlled and measured by deformation gradient tensor involving both the undeformed configuration and the current configuration. Definitions of Biot strain and Cauchy stress are adopted. The expressions of them in terms of contact forces and particle displacements, respectively, are derived. The boundary of the tested specimen consists of rigid massless planar units. It is suggested that the representative element uses a convex polyhedral (polygonal) shape to minimize possible boundary arching effects. General loading paths are described by directly specifying the changes in the stress/strain invariants or directions. Loading can be applied in the strain‐controlled mode by specifying the translations and rotations of the boundary units, or in the stress‐controlled mode by using a servo‐control mechanism, or in the combination of the two methods to realize mixed boundary conditions. Taking the simulation results as the natural consequences originated from a complex system, virtual experiments provide particle‐scale information database to conduct multi‐scale investigations for better understanding in granular material behaviours and possible development of the constitutive theories provided the qualitative similarity between the simulation results from virtual experiments and observations on real material behaviour. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
40.
REN Xueying SUI Zhenghong ZHANG Xuecheng 《中国海洋大学学报(英文版)》2006,5(2):146-150
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) plays important roles in various cellular processes. A cytosolic GAPDH encoding gene (gpd) of Gracilaria/Gracilariopsis lemaneiformis was cloned and characterized. Deduced amino acid sequence of the enzyme of G. lemaneiformis had high homology with those of seven red algae. The 5'-untranslated regions of the GAPDHs encoding genes of these red algae varied greatly. GAPDHs of these red algae shared the highly conserved glyceraldehyde 3-phosphate dehydrogenase active site ASCTTNCL. However, such active site of Cyanidium caldarium was different from those of the other six algae at the last two residues (CL to LF), thus the spatial structure of its GAPDH active center may be different from those of the other six. Phylogenetic analysis indicated that GAPDH of G. lemaneiformis might have undergone an evolution similar to those of Porphyra yezoensis, Chondrus crispus, and Gracilaria verrucosa. C. caldarium had a closer evolutionary relationship with Cyanidioschyzon merolae than with Cyanidium sp. Virtual Northern blot analysis revealed that gpd of G. lemaneiformis expressed constitutively, which suggested that it might be house-keeping and could be adapted as an inner control in gene expression analysis of G. lemaneiformis. 相似文献