Artículos de revistas: Recent submissions
Now showing items 821-840 of 4968
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(1984)We consider systems of differential equations of the form (1) x’ = f(t,x), for t ∊ [a,∞), x in some domain D ⊂ IRn and f ∈ c1 ([a,∞) × D) (a a fixed real number). We assume that the solution x(t,to,xo) of (1) defined for ...
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(1995)In this paper I examine the extent to which contemporary ecological patterns in 42 harvester ant assemblages of three continents can be explained as a result of present-day environments or from differences in the history ...
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Effect of gramine on the feeding behavior of the aphids Schizaphis graminum and Rhopalosiphum padi (1988)The effects of the indole alkaloid gramine on the behavior of the aphids Schizaphis graminum and Rhopalosiphum padi feeding on barley seedlings and on artificial diets were studied. On barley cv. F. Union, which lacks ...
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(1995)This article analyzes the conflict between traditional beliefs, cultural roles, and the search for individuality through the study of Fresia, a young Mapuche woman who renounced shamanistic practice. Her case demonstrates ...
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(1995)We consider a system of the form u’' + au’ = Hv(u, v)-h(t) v’' + bv’ = Hu(u, v)-k(t), where h, k are locally integrable and T-periodic, and H is a C1 function defined on (0,∞)x(0,∞), for which a good model is given by H(u, ...
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(1992)Relative reactivities of potassium persulfate (KPS) and ferrous ammonium sulfate-potassium persulfate (FAS-KPS) systems, in aqueous medium, as initiators for grafting of methyl methacrylate (MMA) onto chitin, were studied. ...
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(Elsevier, 2000)The infrared spectra of the azabipiridyl macrocycle complexes of Ni(II), Cu(II) and Zn(II) were registered between 4000 and 200 cm-1. The spectral assignment allowed to identify the complex formation and structural differences ...
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(1998)The infrared spectra of naphthalocyanine (H2Nc) and its copper(II) complex (CuNc) were registered in the region 4000-450 cm-1. These compounds were deposited onto a smooth copper surface and their specular infrared spectra ...
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(1988)From Schizanthus pinnatus Ruiz et Pav. we have isolated seven new tropan-3α,6β-diol diesters, schizanthines F (1), G (2), H (3), I (4), K. (8), L (9), and M (10), together with tropine, (-) -6β-angeloyloxytropan-3α-ol (5), ...
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(1980)Hydroxamic acid concentration in Gramineae, both natural and incorporated, correlates with resistance to the aphid Metopolophium dirhodum. 2,4-Dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one, a hydroxamic acid isolated ...
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(1996)A theoretical evaluation of inelastic transition amplitudes corresponding to collisions between low-energy electrons (up to 5 eV) and small metallic clusters is presented. The target is excited into a particle-hole state ...
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(1999)In this paper we consider a class of nonlinear singularly perturbed elliptic problems of the form ε2 Δu - u + f(u) = 0 in Ω, for a superlinear, subcritical function f. Here Ω a smooth bounded domain, ε > 0 is a small ...
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(Elsevier, 1999)The IR spectra of the M(mnt)(baba) where M = Ni and Pd, mnt = 1,2-maleonitrile and baba = biacetylbisanyline, were recorded in the high as well in the low energy region. A complete assignment of the observed bands was ...
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(Elsevier, 1999)The possibility of gaining insight into chemical bonding and reactivity through various local temperatures and associated entropy densities is explored. Comparisons of these quantities with other local reactivity descriptors ...
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(1990)The negative ions of the alkaline-earth-metal atoms (Be to Ba) have been studied by means of a pseudopotential model together with configuration- interaction and multiconfiguration self-consistent-field techniques. Only ...
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(1997)We have used a deep CO survey of the third galactic quadrant (May et al. 1993) to derive the physical properties of molecular clouds in the outer Galaxy. Within the range of this survey, from 194° to 270° in galactic ...
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(1995)Deuterium quadrupole splittings from the aromatic ring of a series of deuterium labeled n-alkylpyridinium ions with linear n-alkyl groups from Ci to Cie have been measured using 2H-NMR spectroscopy. These splittings were ...
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(1985)The hydroxamic acid content of leaves of cereals correlates well with resistance to aphids. In maize these compounds were absent from xylem exudates and guttation drops. Lateral veins of leaves of 7-day-old maize plants ...
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(1985)The content of the simple indole alkaloid gramine in barley leaves decreased with age. Conversely, susceptibility to aphids increased in older plants. Population growth rate of the greenbug Schizaphis graminum correlated ...
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(1997)An infrared study of the macrocycles cyclam, cyclamdione and its Cu(II) complexes has been performed. The specular reflectance infrared spectrum was recorded and analyzed for the ligands and complexes deposited onto a ...