959 resultados para matematik årskurs 4-6
Resumo:
情绪表达规则是指一个人应当在恰当的情境中表达恰当的情绪。对情绪表达规则的认知发展是个体社会能力发展的一个重要方面,因此这一主题引起了国内外众多研究者的重视。但目前对童年早期儿童的研究中,大多数只考查了儿童对情绪的外显表达与内隐真实体验的区分,没有同时考查儿童对需要使用情绪表达规则的情境的认知,不能全面真实地揭示儿童对情绪表达规则的认知发展。在本研究中,以个别访谈法考查了4-6岁儿童同一个体在这两个指标上对情绪表达规则认知的发展,以及发展中的个别差异和个体内部差异,并进一步了解情境因素以及心理理论能力、执行抑制能力的发展对它们的影响。主要结果如下: (1)4-6岁儿童对情绪表达规则的认知能力随年龄增长而提高:4岁尚处于发展的萌芽水平,5岁和6岁都处于发展的过渡水平。对于同一年龄的儿童,对情绪表达规则的认知发展存在较大的个体之间的差异。 (2)4-6岁儿童对情绪表达规则的认知也存在较大的个体内部差异:对表情伪装的认知滞后于对需要使用情绪表达规则的情境的认知,对言语伪装的认知优于对表情伪装的认知;在对情绪表达规则的使用中,自我定向的占多数,其次是他人定向,规则定向所占的比例最少。随年龄的增长,自我定向的比例减少,他人定向的比例增多。 (3)情境变量影响4-6岁儿童对情绪表达规则的认知:与同伴交往情境中对需要使用情绪表达规则的情境的认知、对言语伪装的认知优于与长辈交往情境中的有关认知;对需要掩藏消极情绪情境中对表情伪装的认知要优于对需要掩藏积极情绪情境中表情伪装的认知。 (4)4-6岁儿童心理理论能力的发展和执行抑制能力的发展与其对情绪表达规则的认知发展有关。 (5)有关情绪表达规则的提示能够促进儿童对情绪隐私的认知,促进的效果随年龄的增长而提高,6岁的效果最好。
Resumo:
The structure of tris-chloro[2,6-bis(2'-pyridyl)-4-(2'-pyridinium)-1,3,5-triazine]cobalt(II) monohydrate, [Co(C18H13N6)Cl-3]center dot H2O (C2/c (No. 15), a = 7.783(11), b = 22.42(3), c = 11.001(15) angstrom, beta = 90.05(2)degrees), crystallized from the open air reaction of CoCl2 and 2,4,6-tri(2-pyridyl)-1,3,5-triazine in the ionic liquid, N-butyl-N-methyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide is reported. The structure consists of six coordinate cobalt in an octahedral geometry bonded to the tridentate tptz ligand and three chlorines. The non-coordinating pyridyl group in the tptz ligand is protonated (with the protonated nitrogen crystallographically disordered over two possible sites), providing overall charge neutrality for the complex.
Resumo:
The presence of local anisotropy in the bulk, isotropic, and ionic liquid phases-leading to local mesoscopic inhomogeneity-with nanoscale segregation and expanding nonpolar domains on increasing the length of the cation alkyl-substituents has been proposed on the basis of molecular dynamics (MD) simulations. However, there has been little conclusive experimental evidence for the existence of intermediate mesoscopic structure between the first/second shell correlations shown by neutron scattering on short chain length based materials and the mesophase structure of the long chain length ionic liquid crystals. Herein, small angle neutron scattering measurements have been performed on selectively H/D-isotopically substituted 1-alkyl-3-methylimidazolium hexafluorophosphate ionic liquids with butyl, hexyl, and octyl substituents. The data show the unambiguous existence of a diffraction peak in the low-Q region for all three liquids which moves to longer distances (lower Q), sharpens, and increases in intensity with increasing length of the alkyl substituent. It is notable, however, that this peak occurs at lower values of Q (longer length scale) than predicted in any of the previously published MD simulations of ionic liquids, and that the magnitude of the scattering from this peak is comparable with that from the remainder of the amorphous ionic liquid. This strongly suggests that the peak arises from the second coordination shells of the ions along the vector of alkyl-chain substituents as a consequence of increasing the anisotropy of the cation, and that there is little or no long-range correlated nanostructure in these ionic liquids.
Resumo:
We present a study on the effect of the alkyl chain length of the imidazolium ring in 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquids, [C1CnIm][NTf2] (n = 2 to 10), on the mixing properties of (ionic liquid + alcohol) mixtures (enthalpy and volume). We have measured small excess molar volumes with highly asymmetric curves as a function of mole fraction composition (S-shape) with more negative values in the alcohol-rich regions. The excess molar volumes increase with the increase of the alkyl-chain length of the imidazolium cation of the ionic liquid. The values of the partial molar excess enthalpy and the enthalpy of mixing are positive and, for the case of methanol, do not vary monotonously with the length of the alkyl side-chain of the cation on the ionic liquid – increasing from n = 2 to 6 and then decreasing from n = 8. This non-monotonous variation is explained by a more favourable interaction of methanol with the cation head group of the ionic liquid for alkyl chains longer than eight carbon atoms. It is also observed that the mixing is less favourable for the smaller alcohols, the enthalpy of mixing decreasing to less positive values as the alkyl chain of the alcohol increases. Based on the data from this work and on the knowledge of the vapour pressure of {[C1CnIm][NTf2] + alcohol} binary mixtures at T = 298 K reported in the literature, the excess Gibbs free energy, excess enthalpy and excess entropy could be then calculated and it was observed that these mixtures behave like the ones constituted by a non-associating and a non-polar component, with its solution behaviour being determined by the enthalpy.
Resumo:
Inorganic polyphosphate (polyP) is increasingly being recognized as an important phosphorus sink within the environment, playing a central role in phosphorus exchange and phosphogenesis. Yet despite the significant advances made in polyP research there is a lack of rapid and efficient analytical approaches for the quantification of polyP accumulation in microbial cultures and environmental samples. A major drawback is the need to extract polyP from cells prior to analysis. Due to extraction inefficiencies this can lead to an underestimation of both intracellular polyP levels and its environmental pool size: we observed 23-58% loss of polyP using standard solutions and current protocols. Here we report a direct fluorescence based DAPI assay system which removes the requirement for prior polyP extraction before quantification. This increased the efficiency of polyP detection by 28-55% in microbial cultures suggesting quantitative measurement of the intracellular polyP pool. It provides a direct polyP assay which combines quantification capability with technical simplicity. This is an important step forward in our ability to explore the role of polyP in cellular biology and biogeochemical nutrient cycling.
Resumo:
The ability of four ectomycorrhizal basidiomycetes to biotransform 2,4,6-trinitrotoluene (TNT) in axenic culture was tested. All species were capable of TNT biotransformation to a greater or lesser extent. When biotransformation was expressed on a biomass basis 4 out of the 5 isolates tested were equally efficient at transforming TNT. The factors regulating TNT biotransformation were investigated in detail for one fungus, Suillus variegatus. When the fungus was grown under nitrogen limiting conditions the rate of biotransformation decreased relative to nitrogen sufficient conditions, but no decrease was observed under short term carbon starvation. Extracellular enzymes of S. variegatus could transform TNT, but transformation was greater in intact cells. The mycelial cell wall fraction did not degrade TNT. The TNT concentration that caused 50% reduction in biomass (EC50) for S. variegatus was within the range observed for other basidiomycete fungi being between 2-10 μg mL-1. The potential use of ectomycorrhizal basidiomycetes as in-situ bioremediation agents for TNT contaminated soils is discussed.
Resumo:
Référence bibliographique : Rol, 59532