Showing papers by "State University of Campinas published in 1973"
TL;DR: In this paper, the effect of uniaxial pressure perpendicular to the junction on the threshold current of GaAs double-heterostructure lasers and homostructure laser operated at room temperature was studied.
Abstract: The effect of uniaxial pressure perpendicular to the junction on the threshold current of GaAs double-heterostructure lasers and homostructure lasers operated at room temperature was studied. The threshold either first increases with pressure up to a certain critical pressure P o and then decreases, or decreases with pressure from the beginning, depending on whether the laser is operating in a TE or a TM mode with zero pressure. In the first case, the change in the threshold current behavior at P o is accompanied by a change of modes from TE to TM. This behavior is explained by a model, taking into account the splitting of the valence bands of GaAs on application of uniaxial pressure.
46 citations
TL;DR: Tityus serrulatus venom, added to the rat phrenic nerve-diaphragm preparation, elicits spontaneous twitches, potentiates the maximum twitch and causes a delay in its relaxation (veratrine-like effect), and d-tubocurarine prevents or abolishes these effects.
33 citations
TL;DR: In this paper, a comparison of the non-equilibrium phonon distributions induced by photon absorption is made for different semiconductors, and it is found that energetic carriers create preferentially LO-phonons for GaAs where Frohlich type interaction dominates.
29 citations
TL;DR: Partial saturation and change of the slope of the spontaneous emission are observed in CW homostructure GaAs and pulsed homostructures and DH GaAs at the onset of the laser modes.
Abstract: Partial saturation and change of the slope of the spontaneous emission are observed in CW homostructure GaAs lasers and pulsed homostructure and DH GaAs lasers at the onset of the laser modes. An important new effect that we have observed is a reduction of the spontaneous emission above threshold for homostructure lasers. The results are discussed in comparison with the previously published work and a possible explanation for the difference of behavior between homostructure and DH lasers is proposed.
22 citations
TL;DR: 15 cases of keloid blastomycosis observed among the Cniabi Indians of the National Park of Xingu are presented; 10 of these have been described in a previous publication.
Abstract: Keloid blastomycosis, or Jorge Lobo's blastomycosis, was described for tlie first time by Jorge Lobo in 1931.̂ It is a cutaneous mycosis caused by the Paracoccidioides loboiA The dermatologic lesions vary; besides keloid-Iike lesions, papules, nodules, warty formations and scarred areas are seen. According to Lacaz,\"* 58 cases of keloid blastomycosis have been rejoorted in Brazil, Surinan, French Guiana, Venezuela, Colombia, Panama and Costa Rica. Most of the patients came from the Amazon region. In this report we present 15 cases of keloid blastomycosis observed among the Cniabi Indians of the National Park of Xingu; 10 of these have been described in a previous publication.2 The Xingu National Park (Fig. 1) is an Indian reserve located in tlie northern part of the state of Mato Grosso, Central Brazil, o£ apjsroximately 22,000 squaie kilometers. It includes the region formed by the Xingu river and its initial course. The four main Brazilian Indian groups, Xupi, Aruak, Ge and Carib, are repre-
20 citations
19 citations
TL;DR: The addition of monoesters of cafestol to triglycerides obtained by reesterification of coffee oil fatty acids resulted in a behavior similar to that of the original coffee oil when subjecting the mixture to the Wesson procedure, a test for predicting refining losses as discussed by the authors.
Abstract: The addition of monoesters of cafestol to triglycerides obtained by re-esterification of coffee oil fatty acids resulted in a behavior similar to that of the original coffee oil when subjecting the mixture to the Wesson procedure, a test for predicting refining losses. Contrary to expectation, the softening point of the triglycerides remained practically unaffected by the above addition.
19 citations
TL;DR: In this paper, the influence of the lattice temperature on the carrier temperature was investigated and it was found that the higher the temperature the lower the difference between carrier and lattice temperatures, though carriers are always thermalized among themselves.
17 citations
TL;DR: Concluiu-se haver diferencas significativas referentes as medidas de comprimento do verme, distância entre as ventosas oral e acetabular, distênciaEntre a parte anterior dos vermes e a extremidade distal das gonadas e quanto ao numero of testiculos.
Abstract: Foram estudados morfologicamente exemplares de S. mansoni adultos das linhagens de Belo Horizonte (MG), e de Sao Jose dos Campos (SP), Brasil. Concluiu-se haver diferencas significativas referentes as medidas de comprimento do verme, distância entre as ventosas oral e acetabular, distância entre a parte anterior dos vermes e a extremidade distal das gonadas e quanto ao numero de testiculos.
17 citations
TL;DR: In this article, a perturbation theory treatment of ν(CO) is applied to R3MCOR′ and R3 MCOMR3 (M = C, Si, Ge, Sn). Corrected group frequencies, ν*(CO), which exclude effects extraneous to the CO bond are calculated.
14 citations
16 Dec 1973
TL;DR: Esta especie ocorre durante o ano todo e que seus individuos podem ser considerados como perenes; a reproducao vegetativa atraves de brotamento das porcoes basais e bastante eficiente e a regeneracao of ramos cortados faz-se rapidamente atraaves da diferenciacao de uma celula apical.
Abstract: Experiencias e observacoes realizadas com populacoes de Pterocladia capillacea do litoral norte do Estado de S. Paulo (Ubatuba) no periodo de 1968-71 permitiram concluir que: esta especie ocorre durante o ano todo e que seus individuos podem ser considerados como perenes; a reproducao vegetativa atraves de brotamento das porcoes basais e bastante eficiente e a regeneracao de ramos cortados faz-se rapidamente atraves da diferenciacao de uma celula apical.
TL;DR: In this paper, the preparation of compounds with the general formula Ln(ClO4)3.4DB (where Ln = La-Yb, Y; DB = di-n-butyramide) is reported.
TL;DR: In this paper, the original model of de Launay has been extended to include the interionic interactions out to fourth neighbours, and the present scheme has been applied to calculate phonon dispersion curves along the three principal symmetry directions, phonon frequency distribution curves as well as lattice heat capacities of copper, silver, aluminium, nickel and palladium.
Abstract: The original model of de Launay has been extended to include the interionic interactions out to fourth neighbours. The present scheme has been applied to calculate phonon dispersion curves along the three principal symmetry directions, phonon frequency distribution curves as well as lattice heat capacities of copper, silver, aluminium, nickel and palladium. These results are reported here and compared to the experimental findings. Excellent agreement has been obtained throughout between the calculated and experimental results for all the metals studied.
TL;DR: Foram registrados 82 casos humanos autoctones de esquistossomose mansonica supostamenteAutoctones da Represa de Americana, na regiao da Repusa de AmericanA, ao estudo epidemiologico da regiao.
Abstract: Apos conhecimento de casos humanos de esquistossomose mansonica supostamente autoctones da Represa de Americana (Sao Paulo, Brasil) procedeu-se ao estudo epidemiologico da regiao. Foram constatados seis focos localizados junto a Represa. Foram encontradas as seguintes especies de moluscos: Biomphalaria tenagophila; B. straminea; B. peregrina; Drepanotrema cimex; D. lucidum; |Lymnaeidae; Ancylidae e Physidae. Exemplares de Biomphalaria tenagophila coletados nos focos apresentaram indices de infeccao para cercarias de S. mansoni que variaram de 0,9 a 45%. Mus musculus albinos foram infectados com cercarias no laboratorio e nos focos, sendo reproduzido o ciclo do S. mansoni em ambas as condicoes. Foram registrados 82 casos humanos autoctones de esquistossomose mansonica, na regiao da Represa de Americana.
TL;DR: In this article, the effect of photoinjected electrons on the radiative emission spectra of semiconductors was investigated and the observed shift of the photoluminescence spectra, at high excitation levels, towards lower energies was accounted for by the present calculation.
TL;DR: In this article, a phenomenological model for lattice dynamics of b.c. metals is proposed by combining central ion-ion interaction on BVK scheme, angular ion-ions interaction onClark-Gazis-Wallis scheme and electron-ion interactions onKrebs scheme with an essential modification of the dielectric screening function.
Abstract: A phenomenological model for lattice dynamics of b.c.c. metals is proposed by combining central ion-ion interaction on BVK scheme, angular ion-ion interaction onClark-Gazis-Wallis scheme and electron-ion interaction onKrebs’s scheme with an essential modification of the dielectric screening function. Calculated phonon dispersion curves of sodium along all the five principal symmetry directions as well as (Θ−T) curve of it show a good agreement with the experimental findings.
TL;DR: Experimental data of the developing of S. mansoni cercariae of two strains, penetrating through the tails of Mus musculus, led to the conclusion that there is no numerical difference, in the two strain, as for development from cerbariae to adult worm.
Abstract: Foram analisados os dados referentes ao desenvolvimento de cercarias de S. mansoni das linhagens de Belo Horizonte (MG) e de Sao Jose dos Campos (SP), Brasil. Concluiu-se que apos a penetracao das cercarias pelo tegumento dos camundongos, nao houve diferenca significativa quanto ao numero de vermes adultos que se desenvolveram, pertencentes as duas cepas estudadas.
TL;DR: In this article, a study of optical lifetimes as determined from surface conditions is made through Raman lineshape analysis and non-equilibrium phonon distributions induced by energetic photoelectrons.
TL;DR: The adenohypophysis of a total of 73 adult rabbits was studied, 56 (37 males and 19 females) had been submitted to orthostatic collapse and 17 (10 males and 7 females) served as controls, and at 6 or more hours following collapse necrosis of the glandular cells was found.
Abstract: Summary The adenohypophysis of a total of 73 adult rabbits was studied, 56 (37 males and 19 females) had been submitted to orthostatic collapse and 17 (10 males and 7 females) served as controls. The animals either died from collapse or were sacrificed at regular periods of time up to 8 months following it. The first change observed was vacuolar alteration of the glandular cells seen 30 minutes after the collapse. This change is possibly related to a nutritive disturbance mainly hypoxic in nature due to shock. The next change seen was nuclear pyknosis, and at 6 or more hours following collapse necrosis of the glandular cells was found. This necrosis was slight, involving isolated cells or groups of them, and complete regeneration of the adenohypophysis occurred 2 months later.
TL;DR: The point ion axially symmetric model of Lehman et al. has been modified for h.c.p. metals to include the electron-ion interaction on the formalism of Krebs as mentioned in this paper.
TL;DR: In this paper, the vibrational spectrum and lattice heat capacities of lead are calculated on the basis of the extended de Launay's model for cubic metals, and the phonon dispersion curves along three principal symmetry directions, namely [100, [110] and [111], as well as (θ- T ) curves are compared with experimental results.
Abstract: The vibrational spectrum and lattice heat capacities of lead are calculated on the basis of the extended de Launay's model for cubic metals. The phonon dispersion curves along three principal symmetry directions, namely [100], [110] and [111], as well as (θ- T ) curves are presented and compared with experimental results. A reasonable agreement is exhibited between the theory and the experiment.
TL;DR: Bhatia's model was modified to consider interionic interactions out to third neighbours as discussed by the authors, and the electron-ion part of the dynamical matrix was also changed to consider the interionic interaction out to the third neighbor.
TL;DR: Necrotic changes involving small areas of the gastric mucosa in the fundic and body portions were seen in successive stages up to regeneration in rabbits submitted to orthostatic collapse.
Abstract: Twenty-five rabbits were submitted to orthostatic collapse, divided into 6 groups and sacrificed about 4, 24 and 48 hours, 8, 15 and 30 days following collapse; two animals died during collapse and another 72 hours later. Seven animals were used as controls.
TL;DR: Radioautographic reaction appeared over all goblet cells whether in the crypts or in the villi indicating continual synthesis of sulfomucins in mice fed “ad libitum”.
Abstract: Adult male mice fed “ad libitum” were given a single intraperitoneal injection of 35S-sodium sulfate and sacrificed one, three and six hours after. Plastic embedded one micron thick sections from duodenum, jejunum and ileum were radioautographed and the uptake of the 35S by goblet cells was analysed. Goblet cells of the small intestine originate in crypts and migrate to villi reaching their tips where they are released into the intestinal lumen. Radioautographic reaction appeared over all goblet cells whether in the crypts or in the villi indicating continual synthesis of sulfomucins.
By determining the silver grain concentration over goblet cells at different levels of crypts and villi it was shown that the cells of duodenum and jejunum become more active in the synthesis of sulfomucin, when they reach the upper half of the villi. In the ileum, although a similar maturation may occur, the results were not statistically significant.
TL;DR: In this paper, the resonant Raman effect due to irradiation in the spectral region of the charge transfer absorption band of the complex TCNEbenzene is reported.
TL;DR: Elektronenoptischer Nachweis, dass Skorpiongift (Tityus serrulatus) nach i.p. Verabreichung an der quergestreiften Muskulatur der Küchenschabe eine starke nekrosierende Wirkung ausübt.
Abstract: Elektronenoptischer Nachweis, dass Skorpiongift (Tityus serrulatus) nach i.p. Verabreichung an der quergestreiften Muskulatur der Kuchenschabe eine starke nekrosierende Wirkung ausubt.
TL;DR: In this paper, the phonon dispersion relations along the three principal symmetry directions and the lattice heat capacities of solid krypton have been calculated on the basis of the axially symmetric model of Lehmanet al.
Abstract: The phonon dispersion relations along the three principal symmetry directions and the lattice heat capacities of solid krypton have been calculated on the basis of the axially symmetric model of Lehmanet al An excellent agreement has been obtained between the theoretical and experimental results
TL;DR: In this article, the axially symmetric model with the nearest and next-nearest neighbour interactions has been used to calculate the phonon dispersion relations along the three principal symmetry directions, the frequency distribution function versus frequency curve, the lattice heat capacities versus temperature curve and the Debye characteristic temperature versus temperature curves of solid Argon.
Abstract: The axially symmetric model with the nearest and next-nearest neighbour interactions has been used to calculate the phonon dispersion relations along the three principal symmetry directions, the frequency distribution function versus frequency curve, the lattice heat capacities versus temperature curve and the Debye characteristic temperature versus temperature curve of solid Argon. An excellent agreement has been found between the theoretical and experimental results.
TL;DR: Foi estudada a frequencia da copula interespecifica entre especimes de Biomphalaria glabrata e B. tenagophila os resultados da experiencia levaram a conclusao de that ha preferencia pela copula intraespecificas.
Abstract: Foi estudada a frequencia da copula interespecifica entre especimes de Biomphalaria glabrata e B. tenagophila. Os resultados da experiencia levaram a conclusao de que ha preferencia pela copula intraespecifica, ocorrendo, contudo, copulas interespecificas.
TL;DR: In this article, a trap generated potential barrier near the heterojunctionnGa1-x Al x As−pGaAs was shown to cause negative resistance in double heterostructure diodes and the filling and emplying times were measured by observing the breakdown of the barrier with single and double pulses.
Abstract: The previously observed negative resistance in double heterostructure diodes is shown to be caused by a trap generated potential barrier near the heterojunctionnGa1-x Al x As−pGaAs. The filling and emplying times were measured by observing the breakdown of the barrier with single and double pulses. Time resolved spectral measurements confirm the model.