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分形列的收敛特性
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作者 沈晨 《石油化工高等学校学报》 EI CAS 2001年第1期82-84,共3页
对于完备度量空间 (X ,d)及相应的分形空间 (H(X) ,h) ,我们曾得到结论 :如果 (H(X) ,h)中的分形列 {An}收敛 ,则∪∞n =1An 为 (X ,d)的完全有界集 ,{An}的极限limn→∞ An=∩∞n =1∪∞m =nAm,并且 ,当{An}单调增加时 ,∪∞n =1An 的... 对于完备度量空间 (X ,d)及相应的分形空间 (H(X) ,h) ,我们曾得到结论 :如果 (H(X) ,h)中的分形列 {An}收敛 ,则∪∞n =1An 为 (X ,d)的完全有界集 ,{An}的极限limn→∞ An=∩∞n =1∪∞m =nAm,并且 ,当{An}单调增加时 ,∪∞n =1An 的完全有界性亦成为 {An}收敛的充分条件。本文进一步研究了在除去 {An}的单调性情况下 ,借助于∩∞n=1∪∞m =nAm来寻找 {An}收敛的充分必要条件问题 ,得到了其收敛的特征 ,即 {An}收敛当且仅当∪∞n =1An 为 (X ,d)的完全有界集且∩∞n =1∪∞m =nAm =∩{Ani}∈S ∪∞i=1Ani,其中S为 {An}的子列全体 ,“———”表示闭包。 展开更多
关键词 分形空间 分形列 收敛性 完全有界集 完备度量空间
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Partial transmitting sequence method based on trellis factor search 被引量:2
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作者 吴炳洋 程时昕 《Journal of Southeast University(English Edition)》 EI CAS 2005年第2期123-126,共4页
To obtain good trade-offs between complexity and performance onpeak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM)using partial transmitting sequence (PTS) schemes, a trel... To obtain good trade-offs between complexity and performance onpeak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM)using partial transmitting sequence (PTS) schemes, a trellis structure based PTS factor searchmethod is proposed. The trellis search is with a variant constraint length L_C, 1 ≤ L_C ≤ V-1,where V is the number of PTS subblocks. The method is to decide a PTS factor by searching all thepossible paths obtained by varying L_C consecutive factors. The trellis search can be viewed as ageneral PTS factor search model. If L_C = V-1, it is a full search, and if L_C = 1, it is aniterative search. Using different constraint lengths, trellis factor search PTS exhibits differentPAPR reduction performances. A larger L_C results in a better performance and L_C = V-1 results inthe optimum. However, a larger L_C requires more computation. This helps to choose a good trade-offbetween complexity and performance. 展开更多
关键词 peak-to-average power ratio (PAPR) partial transmitting sequence (PTS) trellis search
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Grateloupia ramosa Wang & Luan sp. nov. (Halymeniaceae, Rhodophyta), a new species from China based on morphological evidence and comparative rbcL sequences 被引量:5
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作者 曹翠翠 刘淼 +3 位作者 郭少茹 赵丹 栾日孝 王宏伟 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2016年第2期283-294,共12页
Grateloupia ramosa Wang & Luan sp. nov.(Halymeniaceae, Rhodophyta) is newly described from Hainan Province, southern China. The organism has the following morphological features:(1) purplish red, cartilaginous and... Grateloupia ramosa Wang & Luan sp. nov.(Halymeniaceae, Rhodophyta) is newly described from Hainan Province, southern China. The organism has the following morphological features:(1) purplish red, cartilaginous and lubricous thalli 5–10 cm in height;(2) compressed percurrent axes bearing abundant branches with opposite arrangement;(3) claw-like apices on top, constricted to 2–4 cm at the base;(4) cortex consisting of 3–6 layers of elliptical or anomalous cells and a medulla covered by compact medullary filaments;(5) reproductive structures distributed throughout the thallus, especially centralized at the bottom of the end portion of the branches; and(6) 4-celled Carpogonial branches and 3-celled auxiliary-cell branches, both of the Grateloupia-type. The morphological diff erences were supported by molecular phylogenetics based on ribulose-1, 5-bisphosphate carboxylase/oxygenase( rbc L) gene sequence analysis. There was only a 1 bp divergence between specimens collected from Wenchang and Lingshui of Hainan province. The new species was embedded in the large Grateloupia clade of the Halymeniaceae. The pairwise distances between G. ramosa and other species within Grateloupia ranged from 26 to 105 bp, within pairwise distances of 13–111 bp between species of the large genus Grateloupia in Halymeniaceae. Thus, we propose this new species as G. ramosa Wang & Luan sp. nov. 展开更多
关键词 GRATELOUPIA Grateloupia ramosa HALYMENIACEAE morphology rbcL sequence Rhdophyta
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Morphology and Molecular Identification of Ulva Forming Green Tides in Qingdao,China
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作者 KONG Fanna MAO Yunxiang +2 位作者 CUI Fujun ZHANG Xingkui GAO Zhen 《Journal of Ocean University of China》 SCIE CAS 2011年第1期73-79,共7页
Green tides are caused by the proliferation of chlorophytes under suitable hydrographic conditions.These blooms lead to environmental degradation and negatively impact the waters and seagrass beds,as well as fishing a... Green tides are caused by the proliferation of chlorophytes under suitable hydrographic conditions.These blooms lead to environmental degradation and negatively impact the waters and seagrass beds,as well as fishing and other recreational activities in the bay.A comprehensive ecological understanding of the bloom dynamics,including the origin and persistence,is needed to foster management decisions.The algae in the great majority of green tide blooms usually belong to two genera of Ulvophyceae,Ulva and Enteromorpha.Ulva has been observed more often in recent years.In China,green tides occurred for the first time in the middle area of the Yellow Sea in 2007,and a large-scale algae blooming broke out in the middle and southern areas of the Yellow Sea in late May 2008.We identified them as Ulva prolifera by comparative analysis of the rDNA internal transcribed spacer 1 (ITS1),5.8S and ITS2 sequences in combination with microscopic observation.Morphological differences were found between the free-floating algae and the attached thalli.Various reproduction patterns of the free-floating algae include sexual,asexual and vegetative propagations,which played important roles in the long-term green tide persistence in China.The ITS sequences of the blooming algae were identical to those of the samples from the Lianyungang sea area but were different from the attached samples from the Qingdao sea area.The results infer that the blooms are originated from other sea areas rather than from the local attached populations. 展开更多
关键词 Ulva prolifera green tides ITS sequences monostromatic phylogenetic analysis
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Automatic Tracing and Segmentation of Rat Mammary Fat Pads in MRI Image Sequences Based on Cartoon-Texture Model 被引量:3
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作者 涂圣贤 张素 +4 位作者 陈亚珠 Freedman Matthew T WANG Bin XUAN Jason WANG Yue 《Transactions of Tianjin University》 EI CAS 2009年第3期229-235,共7页
The growth patterns of mammary fat pads and glandular tissues inside the fat pads may be related with the risk factors of breast cancer.Quantitative measurements of this relationship are available after segmentation o... The growth patterns of mammary fat pads and glandular tissues inside the fat pads may be related with the risk factors of breast cancer.Quantitative measurements of this relationship are available after segmentation of mammary pads and glandular tissues.Rat fat pads may lose continuity along image sequences or adjoin similar intensity areas like epidermis and subcutaneous regions.A new approach for automatic tracing and segmentation of fat pads in magnetic resonance imaging(MRI) image sequences is presented,which does not require that the number of pads be constant or the spatial location of pads be adjacent among image slices.First,each image is decomposed into cartoon image and texture image based on cartoon-texture model.They will be used as smooth image and feature image for segmentation and for targeting pad seeds,respectively.Then,two-phase direct energy segmentation based on Chan-Vese active contour model is applied to partitioning the cartoon image into a set of regions,from which the pad boundary is traced iteratively from the pad seed.A tracing algorithm based on scanning order is proposed to accurately trace the pad boundary,which effectively removes the epidermis attached to the pad without any post processing as well as solves the problem of over-segmentation of some small holes inside the pad.The experimental results demonstrate the utility of this approach in accurate delineation of various numbers of mammary pads from several sets of MRI images. 展开更多
关键词 active contours cartoon-texture model tracing boundary sequential images segmentation
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A Preliminary Phylogenetic Analysis of Luidia (Paxillosida: Luidiidae) from Chinese Waters with Cytochrome Oxidase Subunit I (COI) Sequences
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作者 XIAO Ning LIU Ruiyu +1 位作者 YUAN Shuai SHA Zhongli 《Journal of Ocean University of China》 SCIE CAS 2013年第3期459-468,共10页
Luidia Forbes (Paxillosida: Luidiidae) are common soft bottom sea stars with 49 described species. Because of substan- tial morphological diversity, the taxonomy of the genus is complex and hasn't been resolved de... Luidia Forbes (Paxillosida: Luidiidae) are common soft bottom sea stars with 49 described species. Because of substan- tial morphological diversity, the taxonomy of the genus is complex and hasn't been resolved definitely. In order to resolve general taxonomic issues, and determine species boundaries and phylogenetic relationships within the genus Luidia, the sequences of tyro- chrome oxidase subunit I (COI) gene from 24 specimens of Luidia, belonging to eight taxa in Chinese waters, were studied. Three sequences of two species in genus Luidia from GenBank were used to analyze the phylogenetie relationships. The molecular phy- logeny exhibited three main clades, each with strong bootstrap support: Clade A including Luidia quinaria from the Sea of Japan; Clade B including seven nominal species (L. quinaria von Martens, L. yesoensis Goto, L. ehangi Liu, Liao and Li, L. orientalis Fisher, L. avicularia Fisher, L. longispina Sladen and L. hardwicki Gray) from Chinese waters; and Clade C including L. maculata Miiller & Troschel from Chinese waters. Our molecular phylogeny results support the morphological Quinaria-Group and Alter- nata-Group assigned by D6derlein. Seven nominal species we sampled do not exhibit genetic distances that are large enough to rec- ognize them as separate species. Cryptic species may exist in 'Luidia quinaria' from the Yellow Sea and the Sea of Japan. Meaning- ful morphological characters need further investigation in Luidia. 展开更多
关键词 ECHINODERMATA Luidia China DNA taxonomy cryptic species
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Using Array Methods to Identify and Process Weak Signals Generated by the Brightlight(Ⅰ) 50t Explosion 被引量:1
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作者 Hao Chunyue Zheng Zhong Zhang Shuang 《Earthquake Research in China》 2010年第2期190-197,共8页
Waveforms generated by the 50t explosion of project Brightlight ( I ) were recorded by HILR array. Using array techniques, the author performed identification, f-k analysis, velocity spectrum analysis, etc. of the w... Waveforms generated by the 50t explosion of project Brightlight ( I ) were recorded by HILR array. Using array techniques, the author performed identification, f-k analysis, velocity spectrum analysis, etc. of the weak signals. The analysis results show that the signal-to-noise ratio after beamforming was obviously enhanced, and the signal could be clearly shown. The energy from this explosion was mainly concentrated in the 1 -8Hz range from f-k analysis. The velocity spectrum gave clear positions of event phases, which could not be seen in the original weak signals. The maximum energy distribution obtained by the Beaman method is close to the theoretical value in the azimuth-slowness domain. 展开更多
关键词 Brightlight( I explosion HILR seismic array Identification of weak signals Array techniques
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Fractal characteristics and its application in electromagnetic radiation signals during fracturing of coal or rock 被引量:6
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作者 Wang Chao Xu Jiankun +1 位作者 Zhao Xiaoxia Wei Mingyao 《International Journal of Mining Science and Technology》 2012年第2期255-258,共4页
The present study analyzed the electromagnetic radiation(EMR) time series of the destruction process of coal or rock sample under uniaxial loading and the monitoring process in working face by means of fractal geometr... The present study analyzed the electromagnetic radiation(EMR) time series of the destruction process of coal or rock sample under uniaxial loading and the monitoring process in working face by means of fractal geometry,and results of the correlation dimension change curve of EMR time series were obtained.In the meantime,the current study also sought the fractal characteristic to the EMR signals by contrast to the change curve of EMR signals and explored the precursory phenomenon of rock burst.This paper concluded the main findings as followed:the EMR time series of the destruction process of coal or rock sample under uniaxial loading and the monitoring process in working face corresponded to fractal;the correlation dimension of EMR time series reflected the process of coal or rock damage deformation,that is,the inner damage of coal or rock made a change from random to order.In the field application,the correlation dimension served as a new index of forecasting the coal or rock dynamic disaster. 展开更多
关键词 Electromagnetic radiationFractal characteristicCorrelation dimensionRock burst
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Phylogeny of subclass Scuticociliatia(Protozoa,Ciliophora) using combined data inferred from genetic,morphological,and morphogenetic evidence
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作者 伊珍珍 王艳刚 +2 位作者 林晓凤 Khaled A.S.AL-RASHEID 宋微波 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2010年第4期778-784,共7页
Gene sequence-based genealogies of scuticociliates are different from those produced by morphological analyses.For this reason,11 representative scuticociliates and two ambiguously related genera were chosen to test t... Gene sequence-based genealogies of scuticociliates are different from those produced by morphological analyses.For this reason,11 representative scuticociliates and two ambiguously related genera were chosen to test the ability of combined phylogenetic analyses using both gene sequences and morphological/morphogenetic characteristics.Analyses of both the SSrRNA gene sequences and the combined datasets revealed a consistent branching pattern.While the terminal branches and the order level relationships were generally well resolved,the family level relationships remain unresolved.However,two other trees based on ITS1-5.8S-ITS2 region sequences and morphological/morphogenetic characters showed limited information,due to a lack of informative sites in these two datasets.Our data suggest,however,that the combined analysis of morphological/morphogenetic characters and gene sequences did produce some changes to the phylogenetic estimates of this group. 展开更多
关键词 CILIOPHORA Scuticociliatia phylogenetic analyses combined data
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The Research of Fractal Characteristics of the Electrocardiogram in a Real Time Mode
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作者 Valery Antonov Anatoly Kovalenko +1 位作者 Artem Zagaynov Vu Van Quang 《Journal of Mathematics and System Science》 2012年第3期191-195,共5页
The article presents the results of recent investigations into Holter monitoring of ECG, using non-linear analysis methods. This paper discusses one of the modern methods of time series analysis--a method of determini... The article presents the results of recent investigations into Holter monitoring of ECG, using non-linear analysis methods. This paper discusses one of the modern methods of time series analysis--a method of deterministic chaos theory. It involves the transition from study of the characteristics of the signal to the investigation of metric (and probabilistic) properties of the reconstructed attractor of the signal. It is shown that one of the most precise characteristics of the functional state of biological systems is the dynamical trend of correlation dimension and entropy of the reconstructed attractor. On the basis of this it is suggested that a complex programming apparatus be created for calculating these characteristics on line. A similar programming product is being created now with the support of RFBR. The first results of the working program, its adjustment, and further development, are also considered in the article. 展开更多
关键词 Holter monitoring ECG correlation dimension fractal analysis of time series non-linear dynamics of heart rate
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Effect of Long-Term in Vitro Sub-culturing on Quality Degeneration of Sweet Potato Varieties: Morpho- Anatomic Assessment and Simple Sequence Repeats Analysis
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作者 Mihiretu Cherinet Hundayehu Elsa Du Toit +3 位作者 Sunette Laurie Martin Steyn Ria Greyling Nokuthula Myeza 《Journal of Agricultural Science and Technology(A)》 2014年第10期811-821,共11页
The aim of this study was to assess the effect of long-term in vitro sub-culturing on the varietal degeneration of three sweet potato varieties, namely, Monate, Mokone and Ndou which were sub-cultured for 32, 23 and 1... The aim of this study was to assess the effect of long-term in vitro sub-culturing on the varietal degeneration of three sweet potato varieties, namely, Monate, Mokone and Ndou which were sub-cultured for 32, 23 and 12 generations, respectively. Each generation was cultured in a media which is made from 4.43 g/L Murashige and Skoog (MS), 30 g/L sucrose and 2 g/L gelrite, respectively, and grown under 16 h light and 8 h dark photoperiod for 30 d. For each generation, 45 plantlets were acclimatized for two months in a glasshouse. Data on in vitro growth performance and 11 morphological characteristics during acclimatization were recorded. Early root and shoot formation was observed after the 27th and 21st sub-cultured generations of Monate and Mokone, respectively. During acclimatization, plantlets from the same variety showed differences in morphological traits such as leaf colour, abaxial leaf pigmentation, vine pigmentation, petiole pigmentation, leaf wrinkling and flowering. However, the rate of these morphological differences is random and irrespective to increase in sub-culturing. Therefore, to understand the genetic base of these morphological variability, two plantlets from each variety were subjected to genetic analysis by using five simple sequence repeat (SSR) primers (IB-242, IB-318, IB-255F, 1B-248 and IB-255). Although SSR loci IB-255F and IB-318 could distinguish between the three varieties, there were no allelic polymorphisms detected in plantlets from the same varieties. Therefore, long-term sub-culturing do not leads to quality degeneration in the three sweet potato varieties. 展开更多
关键词 MICRO-PROPAGATION ORGANOGENESIS SUB-CULTURE true-to-type morphology polymorphism.
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A Shear-wave Splitting Study of the Yingjiang M_S6.1 Earthquake Sequence Occurring on May 30,2014
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作者 Li Jin Gao Yuan +3 位作者 Xu Fukun Xiang Yang Xiang Yuan Liu Geng 《Earthquake Research in China》 CSCD 2016年第2期177-185,共9页
Earthquakes of M_S5. 6 and M_S6.1 occurred in Yingjiang,Yunnan on May 24 and May 30,2014 respectively. In this paper,we use the waveform data recorded by mobile seismic stations( KAC) which were set up in the source a... Earthquakes of M_S5. 6 and M_S6.1 occurred in Yingjiang,Yunnan on May 24 and May 30,2014 respectively. In this paper,we use the waveform data recorded by mobile seismic stations( KAC) which were set up in the source area after the Yingjiang MS5. 6earthquake on May 24,2014 to study the shear-wave splitting characteristics of Yingjiang M_S6.1 earthquake sequence with the SAM method. The result shows that predominant polarization of fast shear-waves before the M_S6.1 earthquake is consistent with the direction of regional principal compressive stress,and predominant polarization of fast shear-waves before the M_S6.1 earthquake show better consistency and smaller dispersion compared to after the M_S6.1 earthquake,and there may be a deflection for the fast shearwaves predominant polarization between the M_S6.1 earthquake sequence and foreshock sequence. We found that the time-delays generally exhibited a lower level before the M_S6.1earthquake and a relatively higher value after the M_S6.1 earthquake. 展开更多
关键词 Yingjiang earthquake sequence Foreshock Shear-wave splittingPolarization of fast shear-waves Time-delays
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Landslide monitoring with high-resolution SAR data in the Three Gorges region 被引量:18
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作者 MingSheng Liao Jing Tang +2 位作者 Teng Wang Timo Balz Lu Zhang 《Science China Earth Sciences》 SCIE EI CAS 2012年第4期590-601,共12页
Employing the well-known D-InSAR technique,we investigated landslide monitoring in the Three Gorges region using TerraSAR-X data.The experiment demonstrates that using both the amplitude and differential phase allows ... Employing the well-known D-InSAR technique,we investigated landslide monitoring in the Three Gorges region using TerraSAR-X data.The experiment demonstrates that using both the amplitude and differential phase allows us to identify the precise location,deformation and time range of occurrence of certain landslides.To overcome the atmospheric effect on D-InSAR results,a time-series analysis was also carried out.The observed nonlinear relationship between the deformation and water level suggests that reservoir water level fluctuation is one of the major causes of landslides,which is significant in terms of issuing landslide warnings.In addition,the comparison of TerraSAR-X and C-band ASAR data results indicates that TerraSAR-X data provide far more reasonable deformation measurements because of their high temporal and spatial resolutions. 展开更多
关键词 landslide monitoring D-INSAR time series analysis high resolution
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Direct observation of atomic-level fractal structure in a metallic glass membrane 被引量:1
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作者 Hongyu Jiang Jiyu Xu +11 位作者 Qinghua Zhang Qian Yu Laiquan Shen Ming Liu Yitao Sun Chengrong Cao Dong Su Haiyang Bai Sheng Meng Baoan Sun Lin Gu Weihua Wang 《Science Bulletin》 SCIE EI CSCD 2021年第13期1312-1318,M0004,共8页
Determination and conceptualization of atomic structures of metallic glasses or amorphous alloys remain a grand challenge.Structural models proposed for bulk metallic glasses are still controversial owing to experimen... Determination and conceptualization of atomic structures of metallic glasses or amorphous alloys remain a grand challenge.Structural models proposed for bulk metallic glasses are still controversial owing to experimental difficulties in directly imaging the atom positions in three-dimensional structures.With the advanced atomic-resolution imaging,here we directly observed the atomic arrangements in atomically thin metallic glassy membranes obtained by vapor deposition.The atomic packing in the amorphous membrane is shown to have a fractal characteristic,with the fractal dimension depending on the atomic density.Locally,the atomic configuration for the metallic glass membrane is composed of many types of polygons with the bonding angles concentrated on 45°-55°.The fractal atomic structure is consistent with the analysis by the percolation theory,and may account for the enhanced relaxation dynamics and the easiness of glass transition as reported for the thin metallic glassy films or glassy surface. 展开更多
关键词 Metallic glass Atomic-resolution imaging Fractal packing Percolation theory
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Phylogeny of the Labeoninae (Teleostei, Cypriniformes) based on nuclear DNA sequences and implications on character evolution and biogeography 被引量:2
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作者 Lanping ZHENG Junxing YANG Xiaoyong CHEN 《Current Zoology》 SCIE CAS CSCD 2012年第6期837-850,共14页
Abstract The Labeoninae is a subfamily of the family Cyprinidae, Order Cypriniformes. Oromandibular morphology within the Labeoninae is the greatest among cyprinid fishes. Although several phylogenetic studies about l... Abstract The Labeoninae is a subfamily of the family Cyprinidae, Order Cypriniformes. Oromandibular morphology within the Labeoninae is the greatest among cyprinid fishes. Although several phylogenetic studies about labeonines have been undertaken the results have been inconsistent and a comprehensive phylogeny is needed. Further, an incongruence between morphological and molecular phylogeny requires a systematic exploration of the significance of morphological characters on the basis of the molecular phylogeny. In this study, a total of 292 nucleotide sequences from 73 individuals (representing 24 genera and 73 species) of Labeoninae were analyzed. The results of the phylogenetic analysis indicate that there are four major clades within Labeoninae and three monophyletic lineages within the fourth clade. Results of the character evolution show that all oromandibular morphological characters are homoplastically distributed on the molecular phylogenetic tree and suggests that these characters evolved several times during the history of labeonines. In particular, the labeonine, a specific disc on the lower lip, has been acquired three times and reversed twice. These morphological characters do not have systematic significance but can be useful for taxonomy. The results of biogeography suggest that the Labeoninae originated from Southeast Asia and separately dispersed to Africa, East Asia and South Asia. 展开更多
关键词 PHYLOGENY Character evolution BIOGEOGRAPHY LABEONINAE
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Archaeal viruses-novel,diverse and enigmatic 被引量:2
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作者 GARRETT Roger A 《Science China(Life Sciences)》 SCIE CAS 2012年第5期422-433,共12页
Recent research has revealed a remarkable diversity of viruses in archaeal-rich environments where spindles, spheres, fila- ments and rods are common, together with other exceptional morphotypes never recorded previou... Recent research has revealed a remarkable diversity of viruses in archaeal-rich environments where spindles, spheres, fila- ments and rods are common, together with other exceptional morphotypes never recorded previously. Moreover, their dou- ble-stranded DNA genomes carry very few genes exhibiting homology to those of bacterial and eukaryal viruses. Studies on viral life cycles are still at a preliminary stage but important insights are being gained especially from microarray analyses of viral transcripts for a few model virus-host systems. Recently, evidence has been presented for some exceptional archaeal- nspecific mechanisms for extra-cellular morphological development of virions and for their cellular extrusion. Here we sum- marise some of the recent developments in this rapidly developing and exciting research area. 展开更多
关键词 virus morphotypes diversity and evolution life cycle temporal regulation cellular extrusion mechanism
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4D Graphical representation research of DNA sequences 被引量:1
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作者 Chengjie Tan Shanshan Li Ping Zhu 《International Journal of Biomathematics》 2015年第1期47-58,共12页
Graphical representation of DNA sequences is a key component in studying biological problems. In order to gain new insights in DNA sequences, this paper combined the digitized methods of single-base, base pairs and co... Graphical representation of DNA sequences is a key component in studying biological problems. In order to gain new insights in DNA sequences, this paper combined the digitized methods of single-base, base pairs and coding in triplet bases with the times of base appearing, and then a novel 4D graphical representation method of DNA sequences was put forward. It was a one-to-one correspondence of the arbitrary DNA sequence and 4D graphical representation, that avoided causing non-unique 4D graphical representation and overlapping lines. The method could reflect the biological information features of DNA sequence more comprehensively and effectively without any losses. Based on the 4D graphical representation, we used the geometric center of 4D graphical representation as eigenvalue of DNA sequences analyses, which kept the original features of the data, and then established the Euclidean distances and included angles between vectors' ter- minal point for similarity analyses of the first extron of the beta-globulin gene among 11 species. Finally, we established the graph of systematic hierarchical cluster analysis of 11 species to observe more easily the relationship between species. A positive outcome was reached, and the results were in accord with biological taxonomy, which also supported the rationality and effectiveness of the novel 4D graphical representation. 展开更多
关键词 Euclidean distance graphical representation geometric center similarity analysis.
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Fractal characteristics of far-field diffraction patterns for two-dimensional Thue-Morse quasicrystals
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作者 阳明仰 周骏 +2 位作者 L Petti S De Nicola P Mormile 《Optoelectronics Letters》 EI 2011年第5期346-349,共4页
We report a numerical method to analyze the fractal characteristics of far-field diffraction patterns for two-dimensional Thue-Morse (2-D TM) structures. The far-field diffraction patterns of the 2-D TM structures can... We report a numerical method to analyze the fractal characteristics of far-field diffraction patterns for two-dimensional Thue-Morse (2-D TM) structures. The far-field diffraction patterns of the 2-D TM structures can be obtained by the numerical method, and they have a good agreement with the experimental ones. The analysis shows that the fractal characteristics of far-field diffraction patterns for the 2-D TM structures are determined by the inflation rule, which have potential applications in the design of optical diffraction devices. 展开更多
关键词 Diffraction patterns Fractals INTERFEROMETRY Two dimensional
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