1,463,744 research outputs found

    Error Analysis in the Teaching of English

    Full text link
    The main purpose of this article is to discuss the importance of error analysis in the teaching of English as a foreign language. Although errors are bad things in learning English as a foreign language%2C error analysis is advantageous for both learners and teachers. For learners%2C error analysis is needed to show them in what aspect in grammar which is difficult for them%2C where as for teachers%2C it is required to evaluate themselves whether they are successful or not in teaching English.%0D%0AIn this article%2C the writer presented some English sentences containing grammatical errors. These grammatical errors were analyzed based on the theories presented by the linguists. This analysis aimed at showing the students the causes and kinds of the grammatical errors. By this way%2C the students are expected to increase their knowledge on the English grammar. Abstract in Bahasa Indonesia : errors%2C+mistake%2C+over+orrer%2C+covert+error%2C+interference%2C+overgeneralization%2C+grammar%2C+interlingual%2C+intralingual%2C+idiosyncrasies

    Isolation of poliovirus 2C mutants defective in viral RNA synthesis

    Get PDF
    Two poliovirus mutants were isolated that contain an oligonucleotide linker insertion in the 2C-coding region of the viral genome. One, 2C-31, has a strongly temperature-sensitive phenotype and the other, 2C-32, forms small plaques on HeLa cell monolayers at all temperatures. Both mutants have a severe temperature-sensitive defect in viral RNA synthesis but little effect on the types of viral protein that are made. Temperature shift experiments showed that the 2C function is continuously required for viral RNA synthesis to proceed. The 2C mutants could be complemented in trans by mutants with mutations in other viral proteins. Protein 2C is also the locus of the guanidine resistance and dependence mutants, a drug whose action also affects viral RNA synthesis. Thus, protein 2C is one that is needed continually for viral RNA synthesis and, at least with these temperature-sensitive alleles, can be provided in trans

    Energy transport faster than light in good conductors and superconductors

    Full text link
    People need a model to study tachyons whose prediction can be tested easily. The dispersion relation w^2=k^2C^2-a^2C^2 of a low-frequency electromagnetic field in good conductors is equivalent to the energy-momentum equation E^2=p^2C^2-m^2C^4 of a tachyon where the proportionality coefficient is h^2. An experiment in 1980s to measure the phase velocity Vp [1] can be regarded as an indirect evidence of the superluminal velocity V>>c of those photons just equals the rate of energy flow S/w of the field.Instability of the tachyonic field corresponds to the Joule heat. To detect the speed of energy is difficult and we plan to modulate signals to observe the information velocity (speed of points of non-analyticity)[2].Comment: 16 page

    A Note on Symmetries in the Rauzy Graph and Factor Frequencies

    Get PDF
    We focus on infinite words with languages closed under reversal. If frequencies of all factors are well defined, we show that the number of different frequencies of factors of length n+1 does not exceed 2C(n+1)-2C(n)+1.Comment: 7 page

    Di- and Trinuclear Mixed-Valence Copper Amidinate Complexes from Reduction of Iodine

    Get PDF
    Molecular examples of mixed-valence copper complexes through chemical oxidation are rare but invoked in the mechanism of substrate activation, especially oxygen, in copper-containing enzymes. To examine the cooperative chemistry between two metals in close proximity to each other we began studying the reactivity of a dinuclear Cu(I) amidinate complex. The reaction of [(2,6-Me2C6H3N)2C(H)]2Cu2, 1, with I2 in tetrahydrofuran (THF), CH3CN, and toluene affords three new mixed-valence copper complexes [(2,6-Me2C6H3N)2C(H)]2Cu2(μ2-I3)(THF)2, 2, [(2,6-Me2C6H3N)2C(H)]2Cu2(μ2-I) (NCMe)2, 3, and [(2,6-Me2C6H3N)2C(H)]3Cu3(μ3-I)2, 4, respectively. The first two compounds were characterized by UV-vis and electron paramagnetic resonance spectroscopies, and their molecular structure was determined by X-ray crystallography. Both di- and trinuclear mixed-valence intermediates were characterized for the reaction of compound 1 to compound 4, and the molecular structure of 4 was determined by X-ray crystallography. The electronic structure of each of these complexes was also investigated using density functional theory

    Stereoisomerism in pentaerythritol-bridged cyclotriphosphazene tri-spiranes: spiro and ansa 1,3-propanediyldioxy disubstituted derivatives

    Get PDF
    Four isomeric products were isolated and purified from the reaction of 1,3-propanediol with the tetra-spirane cyclophosphazene-organophosphate compound (1): viz. the di-monospiro (2a), di-monoansa (2b) and two monospiro-monoansa derivatives (2c) and (2d). It is shown by 31P NMR spectroscopy on addition of a chiral solvating agent (CSA) that both the di-monospiro (2a) and di-monoansa (2b) derivatives are racemates, as expected, whereas no splitting of NMR signals occurred on addition of CSA to solutions of (2c) and (2d). It is found by X-ray crystallography that the two monospiro-monoansa spirane derivatives, (2c) and (2d), are meso diastereoisomers, which represent a new case of the stereochemistry of bis di-substituted cyclophosphazene derivatives of (1). It is also observed from the 31P NMR spectrum of the reaction mixture, supported by the yields of pure compounds, that formation of a spiro group is about 4.5 times more likely than that of an ansa moiety under the conditions of the reaction
    corecore