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71.
Ron Warren 《The Journal of communication》2005,55(4):847-863
Studies of parental mediation of children's television viewing have included samples of mostly middle- and upper-class Caucasian parents. These studies have only begun to examine mediation in the context of parent-child relationships. This study of 306 low-income, predominately African American mothers assesses macro- and microlevel influences on viewing mediation using Bronfenbrenner's ecological theory of child development. It was hypothesized that factors outside the home (e.g., work hours) influence parents' involvement with children, which, in turn, was predicted to influence viewing mediation. Results supported this model for coviewing and instructive mediation, but not for viewing restrictions. 相似文献
72.
Ron C. Blei 《Probability Theory and Related Fields》1989,81(4):569-584
Summary Stochastic integration in a Lebesgue Stieltjes sense is developed in a general context of multi-linear measure theory based on the Fundamental Grothendieck Inequality and Factorization Theorem.Research partially supported by NSF Grant DMS 8601485 相似文献
73.
74.
75.
Yuri E. M. van der Burgt Magnus Palmblad Hans Dalebout Ron M. A. Heeren André M. Deelder 《Rapid communications in mass spectrometry : RCM》2009,23(1):31-38
Electron capture dissociation (ECD) is an analytical technique in mass spectrometry (MS) that allows detailed structural study of biomolecules to gain insight in their function. In this work the ECD behavior of two peptide hormones oxytocin (OT1) and vasopressin (VP1) was studied. The results of OT1 and VP1 were compared to structural analogues OT2 and VP2, which have similar amino acid sequences but lack the tocin ring. The ECD results showed that both the fragment type (c/z versus b/y) and the cleavage sites (ring versus tail) changed upon opening of the tocin ring. All four peptides were complexed with three different transition metal cations (Zn2+, Ni2+ and Cu2+) and the ECD results were compared to those obtained from the doubly protonated species. The use of various metal ions yielded different cleavages sites within the same peptide. This can be an effect of the metal ion itself, or a consequence of a change in conformation as was suggested earlier. In addition, the type of fragment ion varied for each metal‐complexed peptide, which is in agreement with previous observations. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
76.
Building on the earlier analysis by Berlin (1991) , this paper reviews various studies on integrating mathematics and science in the 1990s and provides some implications for further research. The areas identified for further exploration include comparison of the nature of mathematics and science, epistemological debates in mathematics and in science education, the bases used to emphasize science over mathematics or vice versa, empirical evidence of effectiveness of integration, connections between teacher education programs for integration and teachers' subsequent classroom teaching practices, perceptions of integration on the part of teacher educators, contextual difficulties in implementing integrated approaches and possible solutions, and rationales of integrating mathematics and science through technology. In order to help all students become scientifically literate, which most reform documents call for, more focused attention on integration of curriculum and instruction is necessary. 相似文献
77.
Ron Warner 《电子设计技术》2008,15(2):68-70,75
带服务能够支持三重应用(即支持语音、视频和数据)至第一英里的客户,例如持续发展的小商业和住宅。FTTx中的主角是GPON(吉比特无源光网络,Gigabit Passive Optical Network),它提供较高的带宽替代DSL和电缆的基于光纤的网络。FTTx为家庭的第一英里应用,诸如光纤到户(FTTH), 相似文献
78.
Ron Aharoni 《Combinatorica》2001,21(1):1-4
We prove that in a tripartite 3-graph .
Received March 17, 1999 相似文献
79.
Consider the regular and the conjugacy characters ofS
n as vectors in Euclidean space, with the standard inner product. Asn grows, the angle between them tends to zero and the ratio of their lengths tends to one. The two characters have therefore
asymptotically similar decompositions into irreducible components. 相似文献
80.
We study communications under slowly varying channels, and consider three cases of knowledge of the channel impulse response (CIR): full knowledge, no knowledge, and partial knowledge of the CIR. By partial knowledge, we refer to knowing only either the CIR magnitudes or the CIR phases. It is known that obtaining the exact joint maximum‐likelihood estimate (MLE) of the CFO and the SFO requires a two‐dimensional search. Here, we present a new estimation method which uses the Taylor expansion of the MLE cost function, combined with the best linear unbiased estimator, to obtain a method which does not require such a search. The computational complexity of the new method is evaluated. Numerical simulations demonstrate that the new method approaches the corresponding Cramér‐Rao bound for a wide range of signal‐to‐noise ratios, and has superior performance compared to all other existing methods for approximating the solution for the joint MLE, while maintaining a low computational complexity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献