973 resultados para 22-215


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Cytogenetic analysis of two local populations of microlepidogaster leucofrenatus showed a basic diploid chromosome number (2N) of 54 in both populations. Some fishes were found to have a 2N = 55 or 56 chromosomes due to the presence of one or two large heterochromatic B chromosomes. Specimens of M. leucofrenatus from the Poco Grande stream had 24 metacentrics, 24 submetacentrics, four subtelocentrics, and one submetacentric homomorphic pair in males and one submetacentric/subtelocentric heteromorphic pair in females, whereas individuals of this species from the Marumbi River had 22 metacentrics, 24 submetacentrics, four subtelocentrics, two acrocentrics, and one submetacentric/subtelocentric heteromorphic pair in females. The occurrence of the heteromorphic pair in the females was due to the presence of an extra C-banded segment on the W chromosome. Ag-NORs in both populations were located interstitially on the short arm of the largest metacentric pair. The Poco Grande population had less constitutive heterochromatin than did the Marumbi River population. The speciation process in this fish species is discussed on the basis of heterochromatin distribution.

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Explants of Maytenus aquifolium were induced to form callus and, subsequently, suspension cultures. The isolation of natural products from callus led to the identification of the cytotoxic triterpene quinonemethides, maitenin (1) and 22 beta-hydroxymaitenin (2), A rapid, sensitive and reliable reversed-phase high-performance liquid chromatography method was developed using a Cls column and isocratic elution for the determination of 1 and 2, the elaborated method gave well-resolved peaks for these compounds with good detection response and linearity in the range of 0.08-72.0 mu g. The quantification of 1 and 2 was performed by an external standard method. (C) 1998 John Wiley & Sons, Ltd.

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The purpose of the present study was to verify the memory exponents of power function for area in observers of different age and educational levels (elementary school, high school or undergraduate school), using the psychophysics method of magnitude estimation. For the age level I (17 to 30 years old) there was no difference among educational levels, although for the age level II (45 to 60 years old) the differences were significant. Tn the age level II, there was a tendency for greater variability of the responses for lower educational levels. The data obtained for the age level I did not show the same results, although a significant difference among the three educational levels was observed. We call conclude that the mnemonic processes present different results when we observe the answers from observers with different ages. This result leads us to suppose that the motivational factor related to the stimulus used can interact with the mnemonic processes.

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The Su-Schrieffer-Heeger (SSH) Hamiltonian has been one of most used models to study the electronic structure of polyacetylene (PA) chains. It has been reported in the literature that in the SSH framework a disordered soliton distribution can not produce a metallic regime. However, in this work (using the same SSH model and parameters) we show that this is possible. The necessary conditions for true metals (non-vanishing density of states and extended wavefunctions around the Fermi level) are obtained for soliton concentration higher than 6% through soliton segregation (clustering). These results are consistent with recent experimental data supporting disorder as an essential mechanism behind the high conductivity of conducting polymers. (C) 2001 Elsevier B.V. B.V. All rights reserved.

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Short-term cultures of a collagenase disaggregated ameloblastoma previously diagnosed as an adenoid cystic carcinoma of the salivary gland were shown by cytogenetic analysis to have the clonal karyotype 45,XY,del(10)(p12), -22. The data may indicate that the loss of genes of chromosome 22, as well as of 10p, could be a critical event in the evolutionary pattern of odontogenic neoplasias. (C) Elsevier B.V., 1996

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The karyotypes of 12 species of Psittaciformes new to cytology are described: Lorius hypoinochrous, L. lory and Phigys solitarius of the Loriidae, and Amazona autumnallis, Aratinga jandaya, Eclectus roratus, Pionus maximiliani, P. menstruus, P. senilis, P. seniloides, Poicephalus senegalus and Polytelis alexandrae of the Psittacidae. The karyotypes of Amazona ochrocephala, Ara ararauna, Ara macao, Psittacula krameri, Psittacus erithacus and Pyrrhura molinae of the Psittacidae have been previously described. For reasons of comparison the karyotypes of Aratinga aurea, Forpus xanthopterygius, Brotogeris sanctithomae and B. versicolorus of the Psittacidae are also described. These karyotypes are compared to those in the literature and the karyological relationships in the Psittaciformes are briefly discussed. Microchromosome fusions and translocations and pericentric inversions probably are responsible for the heterogeneity of karyotypes in the Psittaciformes.

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Langmuir monolayers and Langmuir-Blodgett (LB) films have been produced from polyaniline and a biphosphinic ruthenium complex, referred to as Rupy. Strong, repulsive interaction between the two components led to a nonlinear change in area per molecule and surface potential with the concentration of Rupy in the mixed film. Molecular interaction was also denoted in the spectroscopic and electrochemical properties of the Y-type LB transferred films. The Raman spectra of mixed PANI-Rupy films indicated that the degree of oxidation of PANI increased linearly with the concentration of Ropy. With PANI being increasingly oxidized by presence of Rupy, the electroactivity of the mixed films decreased with the amount of Rupy, to become undetectable when the mixed LB film is 501 mol in Rupy. The presence of Rupy caused the electrical properties of the mixed LB films to be less sensitive to environmental changes. The electrical capacitance of a mixed film changed only by 15% when the sample was taken from vacuum to air, whereas the change was 215% for a pure PANI LB film.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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In this study the levels of Cu, Fe, Pb and Zn, determined in hair of healthy children (25-85 months), living at Araraquara (São Paulo, Brasil) are reported. Analytical determinations were carried out by using atomic absorption spectrometry employing an air acetylene flame. The results obtained are discussed with regard to effect of sex and age, as well compared with others analogous studies.

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An experiment with an Elisa hybrid sweet pepper (Capsicum annuum L) crop using fertirrigation system was carried out in greenhouse. The aim of this study was to evaluate the quantitative effects of an increasing soil saline concentration on the production. The saline concentration was changed by the variation of the KC1 and Ca 2NO 3 concentration in order to obtain high soil electrical conductivity (EC) values. Standard fertigation system (1.5 dS m -1) values were used as control parameters. Besides that, the possibility of saline stress attenuation by applying organic material into the soil was studied. It was observed that the EC levels used in the crop were inversely correlated to the fructification index and the fruit mean weight. Under the most severe treatment (6.0 dS m -1) the fruit mean weight was reduced up to 58% and the mean produced fiuit number per plant was also reduced up to 55%, when compared to the obtained results under controlled conditions. These results demonstrated that the EC variation in the soil solution had strong interference on th production parameters selected for the studies.

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In this paper we consider the transmission problem, in one space dimension, for linear dissipative waves with frictional damping. We study the wave propagation in a medium with a component with attrition and another simply elastic. We show that for this type of material, the dissipation produced by the frictional part is strong enough to produce exponential decay of the solution, no matter how small is its size. ©2007 Texas State University.