Artículos de revistas: Recent submissions
Now showing items 841-860 of 4968
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(1992)Previous analyses on the gauge invariance of the action for a generally covariant system are generalized. It is shown that if the action principle is properly improved, there is as much gauge freedom at the end points for ...
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(1982)Toxicity of DIMBOA, the major cyclic hydroxamic acid in maize extracts, to the aphid Schizaphis graminum, was decreased by addition of cysteine to the insect diet. The ld50 for DIMBOA on aphids was, after 24 hr, 2.1 and ...
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(2000)We report measurements of the temperature dependent resistivity ρ(T) of a gold film 70 nm thick deposited on mica preheated to 300°C in UHV, performed between 4 K and 300 K, and measurements of the surface topography of ...
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(1998)The reaction of Cp(dppe)Fel with the dinitriles NC(CH2)nCN n = 3, 4, 6 in CH3OH and using NH4PF6 as halide abstractor afford the monodentate dinitrile complexes [Cp(dppe)Fe- (η1-NC(CH2)nCN)PF6. Treatment of these mononuclear ...
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(1987)The first leaf of 12-day-old barley seedlings, contained 1.3 μmol/g fr. wt gramine while the concentrations were 2.2, 2.0 and 3.1 μmol/g fr. wt in lower and upper epidermis and mesophyll parenchyma, respectively. Gramine ...
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(1999)Sufficient conditions are derived for the existence of a globally attractive almost periodic solution of a single species model given by the nonautonomous Lasota-Wazewska-type delay differential equations,x′t=-δtxt+ptfxt-τ,in ...
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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 ...
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(Elsevier, 1999)In this work, the basis set superposition error (BSSE) has been analyzed for the systems Cu2, Cu3, Cu6 and Cu13 as prototypes of metallic clusters. Various basis sets have been tested. In addition, pseudopotentials of 1- ...
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(1992)The recombinant plasmid pTR‐3 was previously shown to contain part of the 16S and 23S ribosomal RNA genes and the spacer region between the two genes from operon rrnT, from Thiobacillus ferrooxidans. The spacer region was ...
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(Elsevier Ltd, 1997)Oxidative addition of thiols RSH, R = CH3, CH2CH2CH3, CH2C6H5, C(CH3)3 and C6H4Br, by the complex [CpFe(dppe)1] afforded the oxidized thiolate complexes [CpFe(dppe)-SR]PF6. The reaction of [CpFe(dppe)1] with HSC6H4NH2 ...
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HSAB analysis of charge transfer in the gas-phase acid-base equilibria of alkyl-substituted alcohols (American Chemical Society, 1999)A simple model to analyze charge redistribution associated with proton transfer (PT) reaction is derived from a classical ion transport model. The model is applied to the gas-phase acid-base equilibria of alkyl alcohols. ...
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(Elsevier Ltd, 1997)Reactions of complexes [{(η5-C5Me5)MCl2}2] (M = Rh, Ir) and [{(η6-MeC6H4Pri)RuCl 2}2] with the ligand Ph2PCH2SPh in acetone solution led to neutral complexes with the general formula [(ring)MCl2(η1-Ph2PCH2SPh-P)] (1-3). ...
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(Allen Press Inc., 1999)We determined non-shivering thermogensis (NST) and maximum metabolic rate (MMR) as functions of thermal acclimation in a small mammal species in a seasonal environment. We studied the rodent Phyllotis xanthopygus (Muridae) ...
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(Kluwer Academic Publishers-Plenum Publishers, 1991)Hydroxamic acids (Hx) produced by some cereal crops have been associated with allelopathy. However, the release of Hx to the soil by the producing plant-an essential condition for a compound to be involved in allelopathy-has ...
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(Marcel Dekker Inc., 1996)The electronic absorption charge transfer bands in a series of para-substituted benzalketones are analyzed in order to stablish the role of the electron-donor substituent as well as the electronic properties of the molecular ...
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Diurnal changes in zooplankton respiration rates and the phytoplankton activity in two Chilean lakes (Kluwer Academic Publishers, 1989)Respiration rates of natural zooplankton communities were measured for diel cycles in two lakes. Distinct diurnal cycles were observed in Embalse Rapel with high respiratory rates for the spring cladoceran dominated ...
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(1992)The results of an investigation of the infrared spectra of mono(diethylenetriamine)copper(II) compounds are reported, with particular reference to the low-energy region. Most assignments are based on the available literature. ...
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(1989)DIMBOA (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one), a hydroxamic acid from cereals, reacted with primary amines to give an addition compound with two imino groups. Kinetic studies with DIMBOA and with the DIMBOA analogues ...
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(American Chemical Society, 1997)Various density functionals have been tested in calculating atomic and molecular dipole polarizabilities. For atoms, it has been found that the results are not competitive with more sophisticated ab initio methods. Exchange ...
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Partial purification and characterization of a hydroxamic acid glucoside β-d-glucosidase from maize (Elsevier, 1992)β-Glucosidase activities measured in extracts from maize leaves during development gave different curves when p-nitrophenyl β-d-glucopyranoside (PNP-Glc) or hydroxamic acid glucoside (Hx-Glc) were the substrates. The PNP-Glc ...
