889 resultados para Barker frog


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A novel manganese superoxide dismutase (MnSOD) was cloned from bay scallop Argopecten irradians by 3' and 5' rapid amplification of cDNA ends (RACE) PCR. The full-length cDNA of MnSOD was of 1207 bp with a 678 bp open reading frame encoding 226 amino acids. The deduced amino acid sequence contained a putative signal peptide of 26 amino acids. Sequence comparison showed that the MnSOD of A. irradians shared high identity with MnSOD in invertebrates and vertebrates, such as MnSOD from abalone Haliotis discus discus (ABG88843) and frog Xenopus laevis (AAQ63483). Furthermore, the 3D structure of bay scallop MnSOD was predicted by SWISS-MODEL Protein Modelling Server and compared with those of other MnSODs. The overall structure of bay scallop MnSOD was similar to those of zebrafish Danio rerio, fruit fly Drosophila melanogaster, Chinese shrimp Fenneropenaeus chinensis, human Homo sapiens, and had the highest similarity to scallop Mizuhopecten yessoensis and abalone H. discus discus. A quantitative real-time PCR (qRT-PCR) assay was developed to detect the mRNA expression of MnSOD in different tissues and the temporal expression in haemocytes following challenge with the bacterium Vibrio anguillarum. A higher-level of mRNA expression of MnSOD was detected in gill and mantle. The expression of MnSOD reached the highest level at 3 h post-injection with V. anguillarum and then slightly recovered from 6 to 48 h. The results indicated that bay scallop MnSOD was a constitutive and inducible protein and thus could play an important role in the immune responses against V anguillarum infection. (c) 2008 Elsevier Ltd. All rights reserved.

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在指定路径上的运行时间是衡量真空机器人性能的重要指标,使用时间最优轨迹规划方法能够缩短该运行时间.Frog-leg型结构的真空机器人是同时具有主动与从动关节的并联机构,进行轨迹规划之前必须进行运动学及动力学求解.在此基础上提出Frog-leg型结构的真空机器人时间最优轨迹规划方法,规划出在允许最大速度与加速度范围内的加速度、速度与位置曲线.利用Matlab软件进行了仿真研究.仿真实验结果证明,与梯形轨迹规划方法相比,时间最优轨迹规划方法能够在满足加速度力矩约束的条件下显著缩短真空机器人在指定路径上的运行时间。

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The processes of seismic wave propagation in phase space and one way wave extrapolation in frequency-space domain, if without dissipation, are essentially transformation under the action of one parameter Lie groups. Consequently, the numerical calculation methods of the propagation ought to be Lie group transformation too, which is known as Lie group method. After a fruitful study on the fast methods in matrix inversion, some of the Lie group methods in seismic numerical modeling and depth migration are presented here. Firstly the Lie group description and method of seismic wave propagation in phase space is proposed, which is, in other words, symplectic group description and method for seismic wave propagation, since symplectic group is a Lie subgroup and symplectic method is a special Lie group method. Under the frame of Hamiltonian, the propagation of seismic wave is a symplectic group transformation with one parameter and consequently, the numerical calculation methods of the propagation ought to be symplectic method. After discrete the wave field in time and phase space, many explicit, implicit and leap-frog symplectic schemes are deduced for numerical modeling. Compared to symplectic schemes, Finite difference (FD) method is an approximate of symplectic method. Consequently, explicit, implicit and leap-frog symplectic schemes and FD method are applied in the same conditions to get a wave field in constant velocity model, a synthetic model and Marmousi model. The result illustrates the potential power of the symplectic methods. As an application, symplectic method is employed to give synthetic seismic record of Qinghai foothills model. Another application is the development of Ray+symplectic reverse-time migration method. To make a reasonable balance between the computational efficiency and accuracy, we combine the multi-valued wave field & Green function algorithm with symplectic reverse time migration and thus develop a new ray+wave equation prestack depth migration method. Marmousi model data and Qinghai foothills model data are processed here. The result shows that our method is a better alternative to ray migration for complex structure imaging. Similarly, the extrapolation of one way wave in frequency-space domain is a Lie group transformation with one parameter Z and consequently, the numerical calculation methods of the extrapolation ought to be Lie group methods. After discrete the wave field in depth and space, the Lie group transformation has the form of matrix exponential and each approximation of it gives a Lie group algorithm. Though Pade symmetrical series approximation of matrix exponential gives a extrapolation method which is traditionally regarded as implicit FD migration, it benefits the theoretic and applying study of seismic imaging for it represent the depth extrapolation and migration method in a entirely different way. While, the technique of coordinates of second kind for the approximation of the matrix exponential begins a new way to develop migration operator. The inversion of matrix plays a vital role in the numerical migration method given by Pade symmetrical series approximation. The matrix has a Toepelitz structure with a helical boundary condition and is easy to inverse with LU decomposition. A efficient LU decomposition method is spectral factorization. That is, after the minimum phase correlative function of each array of matrix had be given by a spectral factorization method, all of the functions are arranged in a position according to its former location to get a lower triangular matrix. The major merit of LU decomposition with spectral factorization (SF Decomposition) is its efficiency in dealing with a large number of matrixes. After the setup of a table of the spectral factorization results of each array of matrix, the SF decomposition can give the lower triangular matrix by reading the table. However, the relationship among arrays is ignored in this method, which brings errors in decomposition method. Especially for numerical calculation in complex model, the errors is fatal. Direct elimination method can give the exact LU decomposition But even it is simplified in our case, the large number of decomposition cost unendurable computer time. A hybrid method is proposed here, which combines spectral factorization with direct elimination. Its decomposition errors is 10 times little than that of spectral factorization, and its decomposition speed is quite faster than that of direct elimination, especially in dealing with a large number of matrix. With the hybrid method, the 3D implicit migration can be expected to apply on real seismic data. Finally, the impulse response of 3D implicit migration operator is presented.

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笔者收集了大量国内外学者对世界各地碱性花岗岩的研究资料,总结出碱性花岗岩典型的岩石组合主要有以下几种:1、碱性花岗岩、花岗岩、正长岩、辉长岩、斜长岩(BarKer 等 1975)。2、碱性花岗岩、双套花岗岩系列(均为准铝质)、流纹岩、辉长岩、玄武岩(如澳大利亚南部 Collins 等 1982)。3、碱性花岗岩、黄玉流纹岩(准铝或过铝质)(Burt 等 1982)。4、碱性花岗岩、辉长岩、闪长岩、玄武岩' 闪碱流岩等(南大西洋中 Ascension 岛上)(Weis 1983, Harris 等 1982,1983)。新疆现被确认的碱性花岗岩有布尔根碱性花岗岩。黄羊山碱性花岗岩及新源阿拉马勒碱性花岗岩等,这些碱性花岗岩研究程度都不高,有的尚属空白。布尔根碱性花岗岩岩体是 86 年后才发现的。它们被认为是典型的碱性花岗岩。由于研究碱性花岗岩的物质来源及形成方式等问题对花岗研究工作有重要意义。特别是本区域花岗岩的时代及含矿性在阿尔泰花岗岩中更具有特殊意义。因此本文选择布尔根碱性花岗岩为研究对象,并附带其它几个岩体,以弥补这一地区碱性花岗岩研究的空白。

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Urquhart, C., Light, A., Thomas, R., Barker, A., Yeoman, A., Cooper, J., Armstrong, C., Fenton, R., Lonsdale, R. & Spink, S. (2003). Critical incident technique and explicitation interviewing in studies of information behavior. Library and Information Science Research, 25(1), 63-88. Sponsorship: JISC (for JUSTEIS element)

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Pyatt, B. Barker, G. Birch, P. Gilbertson, D. Grattan, J. Mattingly, D. King Solomon's Miners - Starvation and Bioaccumulation? An Environmental Archaeological Investigation in Southern Jordan. Ecotoxicology and Environmental safety 43, 305-308 (1999) Environmental Research, Section B

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McLaren, S. Gilbertson, D. Grattan, J. Hunt, C. Duller, G. Barker, G. Quaternary palaeogeomorphologic evolution of the Wadi Faynan area, Southern Jordan. Palaeogeography, Palaeoclimatology, Palaeoecology. 2004. 205. pp 131-154

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Gillmore, G. Gilbertson, D. Grattan, J. Hunt, C. McLaren, S. Pyatt, B. Banda, R. Barker, G. Denman, A. Phillips, P. Reynolds, T. The potential risk from 222radon posed to archaeologists and earth scientists: reconnaissance study of radon concentrations, excavations and archaeological shelters in the Great cave of Niah, Sarawak, Malaysia. Ecotoxicology and Environmental Safety. 2005. 60 pp 213-227.

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Hunt, C. Elrishi, H. Gilbertson, D. Grattan, J. McLaren, S. Pyatt, B. Rushworth, G. Barker, G. Early-Holocene environments in the Wadi Faynan, Jordan. The Holocene. 2004. 14,6 pp 921-930

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Barker, M. (2005) 'The Lord of the Rings and 'identification': a critical encounter', European Journal of Communication, 20, 3, 353-378 Sponsorship: This research was made possible by a grant from the Economic and Social Research Council (ESRC Grant No. 000-22-0323)

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This is a report on what can be learnt from our world dataset about viewers of The Lord of the Rings who were aged under 16. In this report, I draw both on the world set, and on the UK subset, sometimes drawing comparisons between them. The reason for using both is that, obviously, the world set is so much larger (comprising 24,739 in toto, with 2475 under 16), but the UK set (comprising 3115 in toto, and 306 under 16s) allows us to explore both some of the specificities of responses here, the qualitative meaning of some responses (given we worked in 14 languages, many are inaccessible to us for analysis), and of course their relations to the quantitative patterns that emerge.

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Egan, K., Barker, M. (2006). Rings around the World: Notes on the Challenges, Problems & Possibilities of International Audience Projects. Participations: Journal of Audience & Reception Studies, 3 (2). Sponsorship: This research was made possible by a grant from the Economic and Social Research Council (ESRC Grant No. 000-22-0323)

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Sponsorship: This research was made possible by a grant from the Economic and Social Research Council (ESRC Grant No. 000-22-0323)

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Barker, M.; Arthurs, J. and Harindranath, R. (Eds.). (2001). Controversy: Censorship Campaigns and Film Reception. London: Wallflower Press. RAE2008

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Barkre, M.; Mathijs, E.; Sexton, J.; Egan, K.; Hunter, R. and Selfe, M. (2007). Audiences and Receptions of Sexual Violence in Contemporary Cinema. London: British Board of Film Classification. RAE2008