排序方式: 共有85条查询结果,搜索用时 24 毫秒
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浅议非英语专业英语口语教学改革 总被引:2,自引:0,他引:2
非英语专业学生口语能力有待提高。如何提高学生的口语水平始终是英语教学中的难点和重点。传统教学模式下的大学英语教学束缚了学生学习潜能的发挥。大学英语教学模式的改革可以考虑采用“任务型教学法”。任务型教学模式是20年来交际教学思想的一种发展形态,它把语言运用的基本理念转化为具有实践意义的课堂教学模式。本研究将任务型教学理念应用于非英语专业英语口语教学之中,通过对任务型教学理论的定义、特征和理论基础等方面的阐析,提出任务型口语教学的总体设计思路和具体教学改革措施。 相似文献
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Percept variance is shown to change the additive property of city-block
distances and make city-block distances more subadditive than Euclidean distances.
Failure to account for percept variance will result in the misclassification of city-block
data as Euclidean. A maximum likelihood estimation procedure is proposed for the
multidimensional scaling of similarity data characterized by percept variance. Monte
Carlo and empirical experiments are used to evaluate the proposed approach. 相似文献
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Relative overexpression of X-linked genes in mouse embryonic stem cells is consistent with Ohno's hypothesis 总被引:1,自引:0,他引:1
Lin H Halsall JA Antczak P O'Neill LP Falciani F Turner BM 《Nature genetics》2011,43(12):1169-70; author reply 1171-2
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O'Donovan MC Craddock N Norton N Williams H Peirce T Moskvina V Nikolov I Hamshere M Carroll L Georgieva L Dwyer S Holmans P Marchini JL Spencer CC Howie B Leung HT Hartmann AM Möller HJ Morris DW Shi Y Feng G Hoffmann P Propping P Vasilescu C Maier W Rietschel M Zammit S Schumacher J Quinn EM Schulze TG Williams NM Giegling I Iwata N Ikeda M Darvasi A Shifman S He L Duan J Sanders AR Levinson DF Gejman PV Cichon S Nöthen MM Gill M Corvin A Rujescu D Kirov G Owen MJ Buccola NG Mowry BJ 《Nature genetics》2008,40(9):1053-1055
We carried out a genome-wide association study of schizophrenia (479 cases, 2,937 controls) and tested loci with P < 10(-5) in up to 16,726 additional subjects. Of 12 loci followed up, 3 had strong independent support (P < 5 x 10(-4)), and the overall pattern of replication was unlikely to occur by chance (P = 9 x 10(-8)). Meta-analysis provided strongest evidence for association around ZNF804A (P = 1.61 x 10(-7)) and this strengthened when the affected phenotype included bipolar disorder (P = 9.96 x 10(-9)). 相似文献
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Chromatin immunoprecipitation (ChIP) defines the genomic distribution of proteins and their modifications but is limited by the cell numbers required (ideally >10(7)). Here we describe a protocol that uses carrier chromatin and PCR, 'carrier' ChIP (CChIP), to permit analysis of as few as 100 cells. We assayed histone modifications at key regulator genes (such as Nanog, Pou5f1 (also known as Oct4) and Cdx2) by CChIP in mouse embryonic stem (ES) cells and in inner cell mass (ICM) and trophectoderm of cultured blastocysts. Activating and silencing modifications (H4 acetylation and H3K9 methylation) mark active and silent promoters as predicted, and we find close correlation between values derived from CChIP (1,000 ES cells) and conventional ChIP (5 x 10(7) ES cells). Studies on genes silenced in both ICM and ES cells (Cdx2, Cfc1, Hhex and Nkx2-2, also known as Nkx) show that the intensity of silencing marks is relatively diminished in ES cells, indicating a possible relaxation of some components of silencing on adaptation to culture. 相似文献
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Malek RL Wang HY Kwitek AE Greene AS Bhagabati N Borchardt G Cahill L Currier T Frank B Fu X Hasinoff M Howe E Letwin N Luu TV Saeed A Sajadi H Salzberg SL Sultana R Thiagarajan M Tsai J Veratti K White J Quackenbush J Jacob HJ Lee NH 《Nature genetics》2006,38(2):234-239
Cardiovascular disorders are influenced by genetic and environmental factors. The TIGR rodent expression web-based resource (TREX) contains over 2,200 microarray hybridizations, involving over 800 animals from 18 different rat strains. These strains comprise genetically diverse parental animals and a panel of chromosomal substitution strains derived by introgressing individual chromosomes from normotensive Brown Norway (BN/NHsdMcwi) rats into the background of Dahl salt sensitive (SS/JrHsdMcwi) rats. The profiles document gene-expression changes in both genders, four tissues (heart, lung, liver, kidney) and two environmental conditions (normoxia, hypoxia). This translates into almost 400 high-quality direct comparisons (not including replicates) and over 100,000 pairwise comparisons. As each individual chromosomal substitution strain represents on average less than a 5% change from the parental genome, consomic strains provide a useful mechanism to dissect complex traits and identify causative genes. We performed a variety of data-mining manipulations on the profiles and used complementary physiological data from the PhysGen resource to demonstrate how TREX can be used by the cardiovascular community for hypothesis generation. 相似文献
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Thompson AA Liu W Chun E Katritch V Wu H Vardy E Huang XP Trapella C Guerrini R Calo G Roth BL Cherezov V Stevens RC 《Nature》2012,485(7398):395-399
Members of the opioid receptor family of G-protein-coupled receptors (GPCRs) are found throughout the peripheral and central nervous system, where they have key roles in nociception and analgesia. Unlike the 'classical' opioid receptors, δ, κ and μ (δ-OR, κ-OR and μ-OR), which were delineated by pharmacological criteria in the 1970s and 1980s, the nociceptin/orphanin FQ (N/OFQ) peptide receptor (NOP, also known as ORL-1) was discovered relatively recently by molecular cloning and characterization of an orphan GPCR. Although it shares high sequence similarity with classical opioid GPCR subtypes (~60%), NOP has a markedly distinct pharmacology, featuring activation by the endogenous peptide N/OFQ, and unique selectivity for exogenous ligands. Here we report the crystal structure of human NOP, solved in complex with the peptide mimetic antagonist compound-24 (C-24) (ref. 4), revealing atomic details of ligand-receptor recognition and selectivity. Compound-24 mimics the first four amino-terminal residues of the NOP-selective peptide antagonist UFP-101, a close derivative of N/OFQ, and provides important clues to the binding of these peptides. The X-ray structure also shows substantial conformational differences in the pocket regions between NOP and the classical opioid receptors κ (ref. 5) and μ (ref. 6), and these are probably due to a small number of residues that vary between these receptors. The NOP-compound-24 structure explains the divergent selectivity profile of NOP and provides a new structural template for the design of NOP ligands. 相似文献
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