70 resultados para searching
Resumo:
The parasitic copepod Sinergasilus major is an important pathogen of grass carp Ctenopharyngodon idella. To understand the immune response of grass carp to the copepod infection, suppression subtractive hybridization method was employed to characterize genes up-regulation during the copepod infection in liver and gills of the fish. One hundred and twenty-two dot blot positive clones from infected subtracted library were sequenced. Searching available databases by using these nucleotide sequences revealed that 23 genes are immune-related, including known acute-phase reactants, and four novel genes encoding proteins such as source of immunodominant MHC-associated peptides (SIMP), TNF receptor-associated factor 2 binding protein (T2BP), poliovirus receptor-related protein 1 precursor, glycoprotein A repetitions predominant (GARP). The differential expression of seven immune genes, i.e. GARP, alpha-2-macroglobulin, MHC class I, C3, SIMP, T2BP, transferrin, as a result of infection was further confirmed by RT-PCR, with the up-regulation of alpha-2-macroglobulin, MHC class I, C3, SIMP and T2BP in the liver of infected fish, and down-regulation of SIMP in the gills of infected fish. The present study provides foundation for understanding grass carp immune response and candidate genes for further analysis.
Resumo:
A systemic study was initiated to identify stage-specific expression genes in fish embryogenesis by using suppression subtractive hybridization (SSH) technique. In this study, we presented a preliminary result on screen for stage-specific expression genes between tail bud stage (TBS) and heartbeat beginning stage (HBS) in gynogenetic silver crucian carp (Carassius auratus gibelio). Two SSH plasmid libraries specific for TBS embryos and HBS embryos were constructed, and stage-specific expression genes were screened between the two stages. 1963 TBS positive clones and 2466 HBS positive clones were sampled to PCR amplification, and 1373 TBS and 1809 HBS PCR positive clones were selected to carry out dot blots. 169 TBS dot blot positive clones and 272 HBS dot blot positive clones were sequenced. Searching GenBank by using these nucleotide sequences indicated that most of the TBS dot blot positive clones could not be found homologous sequences in the database, while known genes were mainly detected from HBS dot blot positive clones. Of the 79 known genes, 20 were enzymes or kinases involved in important metabolism of embryonic development. Moreover, specific expressions of partial genes were further confirmed by virtual northern blots. This study is the first step for making a large attempt to study temporal and spatial control of gene expression in the gynogenetic fish embryogenesis.
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In the light of descriptive geometry and notions in set theory, this paper re-defines the basic elements in space such as curve and surface and so on, presents some fundamental notions with respect to the point cover based on the High-dimension space (HDS) point covering theory, finally takes points from mapping part of speech signals to HDS, so as to analyze distribution information of these speech points in HDS, and various geometric covering objects for speech points and their relationship. Besides, this paper also proposes a new algorithm for speaker independent continuous digit speech recognition based on the HDS point dynamic searching theory without end-points detection and segmentation. First from the different digit syllables in real continuous digit speech, we establish the covering area in feature space for continuous speech. During recognition, we make use of the point covering dynamic searching theory in HDS to do recognition, and then get the satisfying recognized results. At last, compared to HMM (Hidden Markov models)-based method, from the development trend of the comparing results, as sample amount increasing, the difference of recognition rate between two methods will decrease slowly, while sample amount approaching to be very large, two recognition rates all close to 100% little by little. As seen from the results, the recognition rate of HDS point covering method is higher than that of in HMM (Hidden Markov models) based method, because, the point covering describes the morphological distribution for speech in HDS, whereas HMM-based method is only a probability distribution, whose accuracy is certainly inferior to point covering.
Resumo:
Based on biomimetic pattern recognition theory, we proposed a novel speaker-independent continuous speech keyword-spotting algorithm. Without endpoint detection and division, we can get the minimum distance curve between continuous speech samples and every keyword-training net through the dynamic searching to the feature-extracted continuous speech. Then we can count the number of the keywords by investigating the vale-value and the numbers of the vales in the curve. Experiments of small vocabulary continuous speech with various speaking rate have got good recognition results and proved the validity of the algorithm.
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Quantum computing is a quickly growing research field. This article introduces the basic concepts of quantum computing, recent developments in quantum searching, and decoherence in a possible quantum dot realization.
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Particle Swarm Optimization (PSO) algorithm is often used for finding optimal solution, but it easily entraps into the local extremum in later evolution period. Based on improved chaos searching strategy, an enhanced particle swarm optimization algorithm is proposed in this study. When particles get into the local extremum, they are activated by chaos search strategy, where the chaos search area is controlled in the neighborhood of current optimal solution by reducing search area of variables. The new algorithm not only gets rid of the local extremum effectively but also enhances the precision of convergence significantly. Experiment results show that the proposed algorithm is better than standard PSO algorithm in both precision and stability.
Resumo:
介绍了DBF表的文件格式和基于自索引的全文查询算法FM-index.针对DBF文件同时包含二进制文件头和纯文本数据记录的特点,以及对查询结果的特定要求,扩充了现有的FM-index算法,使其支持对DBF文件的压缩查询.测试结果表明,虽然FM-index在压缩/解压时间上与WinRAR仍有一段差距,但是FM-index对压缩查询功能的支持大大提高了文件的查询性能.
Resumo:
随着计算机硬件的快速变化,如何充分利用计算机资源,使软件性能尽可能逼近处理器峰值是人们关心的问题.针对特定硬件平台手工优化程序,或者依赖编译器优化技术,存在人工介入,难与硬件更新同步等问题.而采用自适应性能优化技术实现的高性能数学软件包(SANS)如FFTW,ATLAS,PHiPAC,OSKI等,可有效解决前两种方法存在的问题,降低开发成本,提高软件可移植性.针对自适应性能优化技术中,优化参数搜索过程十分耗时的问题,提出对优化搜索过程的评价指标Pt,并给出用此指标控制优化搜索过程的方法.实验表明运用该指标可以在较短的时间内得到一个合理的性能值.
Resumo:
Finding countermodels is an effective way of disproving false conjectures. In first-order predicate logic, model finding is an undecidable problem. But if a finite model exists, it can be found by exhaustive search. The finite model generation problem in the first-order logic can also be translated to the satisfiability problem in the propositional logic. But a direct translation may not be very efficient. This paper discusses how to take the symmetries into account so as to make the resulting problem easier. A static method for adding constraints is presented, which can be thought of as an approximation of the least number heuristic (LNH). Also described is a dynamic method, which asks a model searcher like SEM to generate a set of partial models, and then gives each partial model to a propositional prover. The two methods are analyzed, and compared with each other.
Resumo:
从2006 年10 月24 日至2007 年4 月9 日,采用固定样线法和瞬时扫描法, 对在大山包国家级自然保护区(N27°18′38″~27°29′15″,E103°14′55″~103°23′49″) 内越冬的黑颈鹤种群进行了越冬行为、日间活动节律和越冬栖息地利用的详细调 查,同时对黑颈鹤的春季迁徙行为和冬季黑颈鹤的死亡现象进行了观察和分析。 这些研究有助于我们了解黑颈鹤是采取何种行为模式和栖息地利用模式来适应高 海拔、低温度的环境,同时对如何有效地保护越冬黑颈鹤和合理规划保护区功能 区域有重要的指导作用。 将黑颈鹤的越冬行为分为:取食(Feeding)、搜寻(Searching)、警戒(Vigilance)、 争斗(Fight)、行走(Walk)、飞行(Flight)、休整(Maintenance)和其它(Others) 八种,越冬期间最主要的行为是取食(53.05±4.93)%,其它行为依次为:搜寻 (10.38±1.34)%、警戒(18.75±2.65)%、休整(10.32±4.93)%、行走(4.90±1.59) %、飞行(1.70±0.38)%、争斗(0.36±0.25)%、其它(0.55±0.41)%。单因素 方差分析(One-Way ANOVA)分析表明越冬期间黑颈鹤日间各时间段(1h)和各 月份间行为差异极显著(P<0.05),并呈现出规律的变化。黑颈鹤的取食、警戒、 搜寻行为具明显的早(10:00-11:00)、晚(17:00-18:00)两个活动高峰,中午 13:00~14:00 最低;而休整行为正好相反,呈现出中午高峰、上午和下午低谷的趋 势;另外几种行为节律性表现不明显。黑颈鹤越冬期主要行为的节律变化是受环 境温度变化影响的,温度高时黑颈鹤增加了修整时间减少了取食时间,而温度低 时则减少了修整时间增加了取食时间以维持能量需求,湿度是通过温度对黑颈鹤 产生影响的。每天黑颈鹤都随着太阳的升起开始觉醒,于07:18±0:15 飞离夜栖地, 大雾的天气影响了黑颈鹤的外出觅食,与之相适应的是黑颈鹤相应的推迟了出飞 时间。黑颈鹤所采取的所有行为都表现出了对大山包特殊环境的适应。 在大山包黑颈鹤所利用的栖息共有耕地(farmland)、草地(grassland)、沼泽 (marsh)和浅水水域(water area)四类。选择指数分析表明黑颈鹤对水域有极大 的偏好,其次为沼泽湿地,再次为耕地,而对草地表现为负选择,并且在越冬期 间的各月份之间,对不同栖息利用比率保持一致。这提示我们在进行保护区规划 的时候应该适当增加前三种栖息地的面积以满足黑颈鹤的越冬需求。主成份因子 分析表明黑颈鹤倾向于选择距夜栖地和水源较近、人流较少、干扰较小、无坡或缓坡的低海拔栖息地。处于不同越冬地的越冬黑颈鹤根据当地的实际情况采取不 同的栖息地利用,说明黑颈鹤具有较强的环境适应能力。 调查期间记录到了三只带有彩环的黑颈鹤个体,其中有两只佩戴有卫星发射 器,发射器编号分别为64309 和64311。大山包黑颈鹤种群数量变动的春季和秋季 高峰是由于处于不同越冬地的黑颈鹤迁徙造成的,同时也说明了大山包是在滇东 北和黔西北越冬的黑颈鹤的集散地。黑颈鹤的春季迁徙一般集中在3 月下旬至4 月上旬,在晴朗、微风的上午10:00-11:00 迁徙的黑颈鹤数量最多,说明了天气条 件对黑颈鹤迁徙的重要性。 大山包保护区内的高压输电电线和通信电缆对越冬黑颈鹤构成了极大的威 胁。观察期间共有7 只黑颈鹤因撞上输电电线而死亡,除去一只没有外伤的成体 之外,成幼比例为1:1,大都发生在天气较为恶劣的12 月-2 月之间。发生撞死黑 颈鹤的时候保护区内都有不同程度的大雾笼罩,由于大雾的影响造成可视条件下 降,加之黑颈鹤飞行的机动性差(翼载量大、展弦比不大),造成了黑颈鹤的伤亡.
Resumo:
The spin-reorientation phenomenon in Nd2Fe14B has been investigated using an angular dependent free energy approach. A magnetic Hamiltonian which includes the crystal electric field term and the exchange term has been established using realistic band structure results. The temperature dependence of the molecular field is accounted for by introducing the Brillouin function and the magnetic Hamiltonian is diagonalized within the ground state multiplet of the Nd ion. The eigenstates are then used to form the partition function for the free energy. At each temperature, the direction of the molecular field is obtained by searching for the minimum in the angular parameter space of the free energy. Our calculations show that for Nd2Fe14B, the net magnetic anisotropy direction is canted away from the c axis at a temperature close to the experimentally reported spin-reorientation temperature of 150 K. The temperature dependence of the magnetic structure is found to be very sensitive to the size of the second order crystal field parameter B20.
Resumo:
Quantum computing is a quickly growing research field. This article introduces the basic concepts of quantum computing, recent developments in quantum searching, and decoherence in a possible quantum dot realization.
Resumo:
In protein sequence alignment, residue similarity is usually evaluated by substitution matrix, which scores all possible exchanges of one amino acid with another. Several matrices are widely used in sequence alignment, including PAM matrices derived from homologous sequence and BLOSUM matrices derived from aligned segments of BLOCKS. However, most matrices have not addressed the high-order residue-residue interactions that are vital to the bioproperties of protein.With consideration for the inherent correlation in residue triplet, we present a new scoring scheme for sequence alignment. Protein sequence is treated as overlapping and successive 3-residue segments. Two edge residues of a triplet are clustered into hydrophobic or polar categories, respectively. Protein sequence is then rewritten into triplet sequence with 2 · 20 · 2 = 80 alphabets. Using a traditional approach, we construct a new scoring scheme named TLESUMhp (TripLEt SUbstitution Matrices with hydropobic and polar information) for pairwise substitution of triplets, which characterizes the similarity of residue triplets. The applications of this matrix led to marked improvements in multiple sequence alignment and in searching structurally alike residue segments. The reason for the occurrence of the ‘‘twilight zone,’’ i.e., structure explosion of lowidentity sequences, is also discussed.
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Efforts have been made in our group to study the band structure of odd-odd nuclei in the A similar to 170 mass region. We aimed at providing new data of high-spin states and searching for the low-spin signature inversion in the 2-qp bands built on the pi h(9/2) circle times nu i(13/2) and pi i(13/2)circle times nu i(13/2) configurations. In this talk, main results of our work will be summarized, and some systematic features of signature inversion discussed. The spin and parity assignments for the pi i(13/2) circle times nu i(13/2) band in (184)An could be regarded as firm providing a good example for systematic and theoretical investigations.
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A dynamic measurement system was developed by the Institute of Modern Physics (IMP) for the dipole prototype of Rapid Cycle Synchrotron (RCS) of China Spallation Neutron Source (CSNS). The repetition frequency of RCS is 25 Hz. The probe is a moving arc searching-coil, and the data acquisition system is based on the dynamic analysis modular of National Instrument. To get the error of high order harmonics of the field at basic frequency, the hardware integrator is replaced by a high speed ADC with software filter and integrator. A series of harmonic coefficients of field are used to express the varieties of dynamic fields in space and time simultaneously. The measurement system has been tested in Institute of High Energy Physics (IHEP), and the property of the dipole prototype of RCS has been measured. Some measurement results and the repeatability of system are illustrated in this paper.