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991.
992.
G. S. Kupriyanova 《Applied magnetic resonance》1996,11(1):87-97
A calculation of the complex signals in homonuclear correlation spectra (HOMCOR) of strongly coupled ABX three-spin systems is presented. It is shown that the presence of strong coupling causes the behavior of the cross-peaks to differ significantly from that found in the case of weak coupling. Two classes of connectivity patterns, namely weak and strong connectivity pairs of transitions are distinguished. Closed expressions for the real amplitudes are given. The dependence of the real amplitude on the flip angle of the mixing pulse and on the coupling strength is analyzed. 相似文献
993.
994.
995.
Many biological and medical studies have as a response of interest the time to occurrence of some event, such as the occurrence of a particular symptom or disease, remission, relapse, death due to some specific disease, or simply death. In this paper we study the problem of assessing the effect of potential risk factors on the outcome event of interest through a parametric or semi-parametric frailty model where the lifetimes have a reason to be considered dependent. This dependence may arise because of multiple endpoints within the same individual or because, when studying a single endpoint, there are natural groupings between study subjects. The objective of this paper is to extend both parametric and semi-parametric approaches to regression analysis in which the lifetimes of individuals in a group are effected by the same random frailty which follows a positive stable distribution. Some comparisons of the properties of this frailty distribution with other frailty distributions are made and an example which assesses the effect of a treatment in a litter-matched tumorigenesis study is presented. 相似文献
996.
Ulenikov O. N. Tolchenov R. N. Melekhina E. N. Koivusaari M. Alanko S. Anttila R. 《Journal of Molecular Spectroscopy》1995,170(2)
High resolution Fourier transform spectra of deuterated hydrogen sulfide have been recorded in the region 2400-3000 cm−1. Rotational structures of the ν1 + ν2, ν2 + ν3 bands of D232S, of the ν3 and ν1 + ν2 bands of HD32S, and of the ν1 + ν2 band of HD34S were analyzed. Band centers and rotational, centrifugal distortion, and resonance parameters were obtained, which reproduce the initial values of the upper energy levels within a mean accuracy of 1.39 × 10−4 cm−1 for the states (110) and (011) of D232S, 1.61 × 10−4 cm−1 and 1.82 × 10−4 cm−1 for the states (001) and (110) of HD32S, and 2.09 × 10−4 cm−1 for the state (110) of HD34S, respectively. 相似文献
997.
V. S. Kirilyuk 《Journal of Mathematical Sciences》1995,77(6):3486-3488
We consider an elastic isotropic material containing a fibrous inclusion or a void subject to loads. We study the possibility
of increasing the strength of the material using “control action.” As examples of such actions we consider an additional external
load, application of pressure in the cavities (voids), and variation of the temperature of uniform heating of the medium with
the inclusions. Studies are carried out for two-dimensional problems of linear elasticity theory. From the class of all possible
actions we single out a subclass leading to states of equal strength along the phase interface. We study the efficiency of
these types of action and show that in certain cases they lead to a manifold increase in the strength of the material. We
give the results of numerical studies.
Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 24, 1993, pp. 15–19. 相似文献
998.
999.
Summary G-protein-coupled receptors all share the seven transmembrane helix motif similar to bacteriorhodopsin. This similarity was exploited to build models for these receptors. From an analysis of a multi-sequence alignment of 225 G-protein-coupled receptors belonging to the rhodopsin-like superfamily, conclusions could be drawn about functional residues. Seven residues in the transmembrane regions are conserved throughout all aligned receptors. These residues cluster at the cytosolic side of the transmembrane helices and are for all rhodopsin-like G-protein-coupled receptors implied in signal transduction. An analysis of correlated mutations reveals a number of residues, both in the helices and in the cytosolic loops, that might be important in the signal transduction pathway in subfamilies of this receptor family. 相似文献
1000.
S. A. Malyugin 《Siberian Mathematical Journal》1993,34(2):297-306