Showing papers by "Federal Fluminense University published in 1979"
TL;DR: In this article, the Green function was applied to an Anderson hamiltonian including the interaction of the chemisorbed hydrogen atom with the surface plasmon of the metal substrate.
23 citations
TL;DR: Results suggest that ecdysone inhibits juvenile hormone production in Rhodnius prolixus and normal oviposition and oogenesis can be re-established by a subsequent blood meal without ecDysone, or by the application of a juvenile hormone analogue.
19 citations
TL;DR: In this article, the ionization energy has been determined from isoelectronic comparisons and the value arrived at, 250 400 ± 300 cm-1, is some 9000 cm 1 lower than the presently accepted value.
Abstract: Analysis of recent observations of the Xe III spectrum has yielded revised and extended identifications for the 5s25p3(4S)6s, 7s, 6p, 5d, 6d and 4f levels. Four of the previously known twenty-two levels have been rejected whereas sixteen new levels have been added. The ionization energy has been determined from isoelectronic comparisons. The value arrived at, 250 400 ± 300 cm-1, is some 9000 cm-1 lower than the presently accepted value.
14 citations
TL;DR: Sequential chromatographic fractionation of Rhodnius prolixus midgut homogenate yielded only one endopeptid enzyme, but revealed the presence of carboxypeptidase-A and B-like enzymes, di- and tripeptidases, as well as aminopePTidase activities.
Abstract: Sequential chromatographic fractionation ofRhodnius prolixus midgut homogenate yielded only one endopeptidase, but revealed the presence of carboxypeptidase-A and B-like enzymes, di- and tripeptidases, as well as aminopeptidase activities
13 citations
TL;DR: In this article, the authors estimate the numerical contribution of the interaction between like defects in glasses for the linewidth obtained in acoustical experiments, which gives origin to a diffusion process with a very large diffusion constant (D = 10 −5 cm 2 sec −1 ).
9 citations
TL;DR: The addition of sucrose to the incubation medium as the extracellular marker markedly decreased the intracellular concentration of Cl− in control retinas, blocked the inward movement of this ion to the tissue during SD and also changed the K+ movement during the phenomenon in medium with 2 mM MgSO4.
Abstract: Total content of water, extracellular space (ES), Na+, K+, and Cl− in the isolated chick retina were measured in the presence (test) or absence (control) of spreading depression (SD). During SD in medium with 0.5 mM or 2 mM MgSO4, there is an increase in the intracellular concentration of Na+ and Cl− and a decrease in the intracellular concentration of K+. A decrease in the ES was only found in the medium with 2 mM MgSO4 together with a diminshed outmovement of K+. We suggest that a decrease in the ES is due to an increased absorption of K+ by the Muller cells, causing its swelling and consequently a decrease of the ES.
8 citations
TL;DR: In this paper, the propagation of magnetic excitations in amorphous ferromagnets is studied from the point of view of the theory of random frequency modulation, and a criterion of validity of perturbation theory is found which is identical to a narrowing condition in magnetic resonance.
Abstract: The propagation of magnetic excitations in amorphous ferromagnets is studied from the point of view of the theory of random frequency modulation. It is shown that the spin waves in the hydrodynamic limit are well described by perturbation theory while the roton-like magnetic excitations with wave vector about the peak in the structure factor are not. A criterion of validity of perturbation theory is found which is identical to a narrowing condition in magnetic resonance.
Nous etudions la propagation des excitations magnetiques dans les solides amorphes ferromagnetiques du point de vue da la theorie de modulation aleatoire de frequence. Nous montrons que les ondes de spins dans la limite hydrodynamique sont bien decrites par la theorie de perturbation, et que les excitations magnetiques rotoniques, de vecteurs d'onde pres du maximum du facteur de structure, ne le sont pas. On obtient une condition de validite de la theorie de perturbation qui est identique a la condition de retrecissement de la raie (“narrowing condition”) dans la theorie de resonance magnetique.
7 citations
TL;DR: In this paper, a graphical method for obtaining diamagnetic anisotropy of certain conjugated systems relative to that of benzene is proposed, and the conjugation volume required is determined through the π charge density contour line of maximum conjugations.
7 citations
7 citations
TL;DR: In this paper, a generalization of the concept of electric-dipole moment is proposed for static dipoles in curved manifolds, and the behaviour of the fields both for the dipole very near and very far from the singular surface of the Reissner-Nordstrom geometry is studied.
Abstract: By using the solution of Adler and Das for Maxwell's equations in a Reissner-Nordstrom optimally charged background metric, the field of a static electric dipole is found and then, by a duality rotation, we find the field of a static magnetic dipole. A generalization of the concept of electric-dipole moment is proposed for static dipoles in curved manifolds, and the behaviour of the fields both for the dipole very near and very far from the singular surface of the Reissner-Nordstrom geometry is studied.
TL;DR: In this article, the mutual polarization of a magnetic electron gas and a van Vleck ion, interacting via exchange, is theoretically investigated using the double-time Green function method, and an analytic expression for the electron gas polarization is obtained which depends on the square of the exchange parameter.
Abstract: The mutual polarization of a magnetic electron gas and a van Vleck ion, interacting via exchange, are theoretically investigated using the double-time Green function method. A pair of equations describing the dynamics of the electron gas and the ion are conveniently decoupled and an analytic expression for the electron gas polarization is obtained which depends on the square of the exchange parameter. Besides a RKKY-like term, a new term associated to the process of formation of the magnetic moment of the ion appears.
Les polarisations mutuelles d'un gaz electronique magnetise et d'un ion van Vleck, interagissant par echange, sont etudiees theoriquement en utilisant la methode de la fonction de Green a double temps. Les paires d'equations decrivant la dynamique du gaz electronique et de l'ion sont decouplees. On obtient une expression analytique de la polarisation du gaz electronique, dependant du carre du parametre d'echange. Outre un terme du type RKKY, il apparǎit un nouveau terme associe au processus de formation du moment magnetique de l'ion.
TL;DR: The clinical and laboratorial study of two brothers with gargoylism concluded that mucolipidose type II should be concidered in any patient with gargoylelism.
Abstract: Foi feito estudo clinico e laboratorial de dois irmaos com manifestacoes clinicas semelhantes ao gargoilismo. Os exames de urina mostraram excrecao normal de mucopolissacarideos. Linfocitos vacuolizados foram encontrados. Os autores fazem consideracoes sobre as mucolipidoses e concluem que nos casos apresentados trata-se provavelmetne de mucolipidose tipo II.