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排序方式: 共有447条查询结果,搜索用时 109 毫秒
321.
ASimulantModelofDevelopmentofAnimalHusbandryandApplicationHEChangzheng;XUJiuping;LIUGuangzhong(Dept.ofAppliedMathematics,Chen... 相似文献
322.
WANG Xiaolan WENG Qingmei YOU Aiqing ZHU Lili & HE Guangcun Key Laboratory of the Ministry of Education for Plant Developmental Biology College of Life Sciences Wuhan University Wuhan China Correspondence should be addressed to He Guangcun 《科学通报(英文版)》2003,48(18):1976-1981
Histones are basic low molecular weight proteins found in all eukaryotic genomes. The histones include five classes of basic proteins (H1, H2A, H2B, H3 and H4) that interact with each other and nuclear DNA to form the nucleosome. The H3 and H4 histone proteins are highly conserved and form the central tetrameric block of the core-nucleosome. Histone H3 has several post-transcrip- tional modifications such as methylation, acetylation, phosphonation, and ADP-ribosylation and it plays impor… 相似文献
323.
A robust H∞ approach to filtering for a class of uncertain linear systems with time-delayed measurement is investigated.The parameter uncertainties are described by real time-varying norm-bounded form.A methodology is developed for designing linear filters such that the filtering process remains robustly stable and the transfer function from the disturbance inputs to error state outputs meets the prescribed H∞-bound constraints.The filter can be obtained and parameterized by solving two Riccati equations based on the lemma of robust stability for control system with delay.Simulation example proves the method to be effective and feasible. 相似文献
324.
MostareasofChinaSeasbelongtocase 2water ,andthealgorithmbasedontheratioofgreentoblueisnotsuitabletothoseareas[1] becausetwoormoresubstanceswithdifferentopticalpropertiesarepre sentedwhichdonotco varywithchlorophyllacon centration .Thesemightbewaterwithexceptionalplanktonblooms (suchasredtides) ,discoloredbyretainedandorganicsuspendedmaterialsandthedis solvedorganismmaterial (DOM ) ,suchasacids .Itis,therefore ,essentialtodevelopmorechannelswithmoresensitivesensorsforChinesecoastalwaterdetec … 相似文献
325.
HE Kun ZHAO Yong 《武汉大学学报:自然科学英文版》2007,12(2):260-266
A new heuristic approach that resembles the evolution of interpersonal relationships in human society is put forward for the problem of scheduling multitasks represented by a directed acyclic graph. The algorithm includes dynamic-group, detachgraph and front-sink components. The priority rules used are new. Relationship number, potentiality, weight and merge degree are defined for cluster's priority, and task potentiality for tasks' priority. Experiments show the algorithm could get good result in short time. The algorithm produces another optimal solution for the classic MJD benchmark. Its average performance is better than five latter-day representative algorithms, especially six benchmarks of the nines. 相似文献
326.
ZHANG Ruping HE Lifang 《武汉大学学报:自然科学英文版》2007,12(2):322-326
A sensitive analytical method, constant-energy synchronous fluorimetry, has been used to determine benzo[a]pyrene (BaP) selectively in airborne particulates (AP). A constant-energy difference of 1 400 cm^-1 was selected for obtaining single spectral peak. The method could easily identify BaP in an 18-component polycylic aromatic hydrocarbons(PAHs) mixtures. Calibration plots in methanol solution and in sodium dodecylsulfate (SDS) micellar media show a good linearity (R〉0.999) in the BaP concentration range generally fotund in the environment. The method gives a detection limit of 0.40 nmol/L in SDS micellar medium and 1.34 nmol/L in methanol solution. 相似文献
327.
Mitochondrial cytochrome b sequence variations and phylogeny of the East Asian bagrid catfishes 总被引:1,自引:0,他引:1
The mitochondrial DNA cytochrome b gene was sequenced from 8 bagrid catfishes in China. Aligned with cytochrome b sequences from 9 bagrid catfishes in Japan, Korea and Russia retrieved from GenBank, and selected Silurus meridionalis, Liobagrus anguillicauda, Liobagrus reini and Phenacogrammus interruptus as outgroups, we constructed a matrix of 21 DNA sequences. The Kimura's two-parameter distances were calculated and molecular phylogenetic trees were constructed by using the maximum parsimony (MP) and neighbor-joining (NJ) methods. The results show that (i) there exist 3-bp deletions of mitochondrial cytochrome b gene compared with cypriniforms and characiforms; (ii) the molecular phylogenetic tree suggests that bagrid catfishes form a monophyletic group, and the genus Mystus is the earliest divergent in the East Asian bagrid catfishes, as well as the genus Pseudobagrus is a monophyletic group but the genus Pelteobagrus and Leiocassis are complicated; and (iii) the evolution rate of the East Asian bagrids mitochondrial cytochrome b gene is about 0.18%~0.30% sequence divergence per million years. 相似文献
328.
IntroductionInrecentyears,multimediacommunicationhasdevelopedrapidly,whererealtimevideoisgetingmoreandmoreimportant.Variable... 相似文献
329.
Hung RJ McKay JD Gaborieau V Boffetta P Hashibe M Zaridze D Mukeria A Szeszenia-Dabrowska N Lissowska J Rudnai P Fabianova E Mates D Bencko V Foretova L Janout V Chen C Goodman G Field JK Liloglou T Xinarianos G Cassidy A McLaughlin J Liu G Narod S Krokan HE Skorpen F Elvestad MB Hveem K Vatten L Linseisen J Clavel-Chapelon F Vineis P Bueno-de-Mesquita HB Lund E Martinez C Bingham S Rasmuson T Hainaut P Riboli E Ahrens W Benhamou S Lagiou P Trichopoulos D Holcátová I Merletti F Kjaerheim K 《Nature》2008,452(7187):633-637
Lung cancer is the most common cause of cancer death worldwide, with over one million cases annually. To identify genetic factors that modify disease risk, we conducted a genome-wide association study by analysing 317,139 single-nucleotide polymorphisms in 1,989 lung cancer cases and 2,625 controls from six central European countries. We identified a locus in chromosome region 15q25 that was strongly associated with lung cancer (P = 9 x 10(-10)). This locus was replicated in five separate lung cancer studies comprising an additional 2,513 lung cancer cases and 4,752 controls (P = 5 x 10(-20) overall), and it was found to account for 14% (attributable risk) of lung cancer cases. Statistically similar risks were observed irrespective of smoking status or propensity to smoke tobacco. The association region contains several genes, including three that encode nicotinic acetylcholine receptor subunits (CHRNA5, CHRNA3 and CHRNB4). Such subunits are expressed in neurons and other tissues, in particular alveolar epithelial cells, pulmonary neuroendocrine cells and lung cancer cell lines, and they bind to N'-nitrosonornicotine and potential lung carcinogens. A non-synonymous variant of CHRNA5 that induces an amino acid substitution (D398N) at a highly conserved site in the second intracellular loop of the protein is among the markers with the strongest disease associations. Our results provide compelling evidence of a locus at 15q25 predisposing to lung cancer, and reinforce interest in nicotinic acetylcholine receptors as potential disease candidates and chemopreventative targets. 相似文献
330.
HE Zhenya CHEN Hua 《武汉大学学报:自然科学英文版》2007,12(3):391-394
We consider the following non-linear elliptic equation △u+ f(x,u)=0,x∈K on fractal domains with zero-Dirichlet boundary conditions, where K is self-similar fractal, △ is the Laplacian defined on K. f(x, t) is asymptotically linear as t→ ∞. We get the non-trivial and non-negative solution by using Mountain Pass lemma. 相似文献