牙鲆淋巴囊肿病毒中国株(LCDV-C)羟类固醇脱氢酶基因的特征分析

属于虹彩病毒科的淋巴囊肿病毒(Lymphoeystisdiseasevirus,LCDV)是一类能引起全球各地上百种淡、海水鱼产生囊肿的病原。在新分离到淋巴囊肿病毒中国株(LymphocystisdiseasevirusisolatefromChina,LCDV—C)并完成序列测定的基础上,用计算机辅助分析了LCDV—C羟类固醇脱氢酶(hydroxysteroiddehydrogenase,HSD)基因结构特征,LCDV—CHSD读码框为1023bp,推导其编码含340个氨基酸、分子量约为39.3kD的蛋

Gaussian processes for POMDP-based dialogue manager optimization

A partially observable Markov decision process (POMDP) has been proposed as a dialog model that enables automatic optimization of the dialog policy and provides robustness to speech understanding errors. Various approximations allow such a model to be used for building real-world dialog systems. However, they require a large number of dialogs to train the dialog policy and hence they typically rely on the availability of a user simulator. They also require significant designer effort to hand-craft the policy representation. We investigate the use of Gaussian processes (GPs) in policy modeling to overcome these problems. We show that GP policy optimization can be implemented for a real world POMDP dialog manager, and in particular: 1) we examine different formulations of a GP policy to minimize variability in the learning process; 2) we find that the use of GP increases the learning rate by an order of magnitude thereby allowing learning by direct interaction with human users; and 3) we demonstrate that designer effort can be substantially reduced by basing the policy directly on the full belief space thereby avoiding ad hoc feature space modeling. Overall, the GP approach represents an important step forward towards fully automatic dialog policy optimization in real world systems. © 2013 IEEE.

Design and fabrication of polarization-independent micro-ring resonators

Origin of polarization sensitivity of photonic wire waveguides (PWWs) is analysed and the effective refractive indices of two different polarization states are calculated by the three-dimensional full-vector beam propagation method. We find that PWWs are polarization insensitive if the distribution of its refractive index is uniform and the cross section is square. An MRR based on such a polarization-insensitive PWW is fabricated on an 8-inch silicon-on-insulator wafer using 248-nm deep ultraviolet lithography and reactive ion etching. The quasi-TE mode is resonant at 1542.25 nm and 1558.90 nm, and the quasi-TM mode is resonant at 1542.12 nm and 1558.94 nm. The corresponding polarization shift is 0.13 nm at the shorter wavelength and 0.04 nm at the longer wavelength. Thus the fabricated device is polarization independent. The extinction ratio is larger than 10 dB. The 3 dB bandwidth is about 2.5 nm and the Qvalue is about 620 at 1558.90 nm.

Parallel Fully-Implicit Computation of Magnetohydrodynamics Acceleration Experiments

A three-dimensional MHD solver is described in the paper. The solver simulates reacting flows with nonequilibrium between translational-rotational, vibrational and electron translational modes. The conservation equations are discretized with implicit time marching and the second-order modified Steger-Warming scheme, and the resulted linear system is solved iteratively with Newton-Krylov-Schwarz method that is implemented by PETS,: package. The results of convergence tests arc plotted, which show good scalability and convergence around twice faster when compared with the DPLR method. Then five test runs are conducted simulating the experiments done at the NASA Ames MHD channel, and the calculated pressures, temperatures, electrical conductivity, back EMF, load factors and flow accelerations are shown to agree with the experimental data. Our computation shows that the electrical conductivity distribution is not uniform in the powered section of the MHD channel, and that it is important to include Joule heating in order to calculate the correct conductivity and the MHD acceleration.

不同光强条件下树木释放N_2O的研究

首次采用封闭罩法 ,对阳生树木 (水曲柳、红松和赤杨 )及阴生树木 (椴树 )的连体及离体枝叶在不同光强下的N2 O释放进行了野外原位观测 .结果表明 ,阳生树木与阴生树木的N2 O释放对光的反应不同 .阳生树木的N2 O释放受光强的调节规律同以往对农作物等的研究结果一致 ;而阴生树木椴树的N2 O释放速率在强光下N2 O释放较多 ,弱光下释放减少甚至吸收大气N2 O ,其N2 O释放速率与光强呈显著线性正相关关系 .

第94届美国生态学会年会在新墨西哥州阿尔伯克基召开

<正>美国生态学会(ESA)第94届年会于2009年8月2日到7日在新墨西哥州阿尔伯克基(Albuquerque)的国际会议中心举行,3000多人参加此次会议。会议主题是"Ecological Knowledge and a Global Sustainable Society"。8月2日下午5时,美

Considerable effects of diversity indices and spatial scales on conclusions relating to ecological diversity

The relationships between ecological diversity and ecosystem functions such as stability and productivity have long been debated and have no final conclusion until now. It is ignored that the debate should be firstly based on the same diversity index, which should be theoretically complete, and on same observation scale. For the issue on the scale of ecotope observation, ecosystems should be distinguished according to intensity of human disturbance. For the issue on the scale of species observation, either number diversity or biomass diversity should be identified. This paper takes grassland ecosystems located within the Bayin Xile grassland of Xilin Gol League of Inner Mongolia Autonomous Region as an example to analyze effects of different diversity indices and spatial scales on the conclusions of ecological diversity and its relationships with ecosystem functions. The analysis results both on the scale of ecotope observation and on the scale of species observation show that different diversity indices might give different conclusions and spatial resolution has a great effect on the relative conclusions. (c) 2005 Elsevier B.V. All rights reserved.

Effect of cavitations on brittle-ductile transition of particle toughened thermoplastics

In this study, we established a correlation between cavitations volume and the brittle-ductile transition (BDT) for particle toughened thermoplastics. The brittle-ductile transition temperature (T-BD) was calculated as a function of T* and interparticle distance (ED), respectively, where T* was a parameter related to the volume of cavitations. The results showed that the smaller the cavitations volume, the higher the brittle-ductile transition temperature. The calculations correlated well with the experimental data. With respect to rubber particle, the rigid particle was too hard to be voided during deformation, thereby the TED of the blend was much higher than that of rubber particle toughened thermoplastic. This was a main reason that rubber particle could toughen thermoplastics effectively, whereas rigid particle could not.