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D. O. Souza R. D. Dias M. A. Carrasco I. Izquierdo 《Cellular and molecular life sciences : CMLS》1980,36(5):539-540
Summary Shuttle avoidance training decreased the cAMP content of rat brain (excluding hippocampus and caudate nucleus), amygdala and hypothalamus. Stimulation by tones alone had a similar effect, but only in the brain fraction. Pseudoconditioning or footshocks alone had no effect.With support from FAPERGS, CNPq, and PROPESP-UFRGS, Brasil. We are grateful to Miss Sonia Eisinger for her valuable technical assistance. 相似文献
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Marlene Benchimol R. D. Machado Wanderley de Souza 《Cellular and molecular life sciences : CMLS》1979,35(5):670-671
Summary Microtubules were observed in the cytoplasm of theElectrophorus electricus L. when the tissue was fixed in the presence of alcian blue and lanthanum nitrate.Supported by grants from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Conselho de Ensino para Graduados da UFRJ, and FINEP. 相似文献
55.
Goetz W Bertelsen P Binau CS Gunnlaugsson HP Hviid SF Kinch KM Madsen DE Madsen MB Olsen M Gellert R Klingelhöfer G Ming DW Morris RV Rieder R Rodionov DS de Souza PA Schröder C Squyres SW Wdowiak T Yen A 《Nature》2005,436(7047):62-65
The ubiquitous atmospheric dust on Mars is well mixed by periodic global dust storms, and such dust carries information about the environment in which it once formed and hence about the history of water on Mars. The Mars Exploration Rovers have permanent magnets to collect atmospheric dust for investigation by instruments on the rovers. Here we report results from M?ssbauer spectroscopy and X-ray fluorescence of dust particles captured from the martian atmosphere by the magnets. The dust on the magnets contains magnetite and olivine; this indicates a basaltic origin of the dust and shows that magnetite, not maghemite, is the mineral mainly responsible for the magnetic properties of the dust. Furthermore, the dust on the magnets contains some ferric oxides, probably including nanocrystalline phases, so some alteration or oxidation of the basaltic dust seems to have occurred. The presence of olivine indicates that liquid water did not play a dominant role in the processes that formed the atmospheric dust. 相似文献
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Helena de Souza Santos W. da Silva Sasso 《Cellular and molecular life sciences : CMLS》1973,29(4):473-474
Resumen Es estudiada la ultraestructure y la histochimica de gránulos de secreción de células glandulares mucosas del pié ambulacrario de la estrella de marEchinaster brasiliensis. Estos gránulos secretores tienen una organización distincta comparada con aqueles encuentrados en la estrella del marAsternia stellifera anteriormente estudiada. Así son organizados en forma de circolos concentricos en torno du un eixo.
Acknowledgments. The authors wish to express their thanks to Mrs.Arlene Mayhugh for her valuable technical assistance. This work was, in part, supported by grants from the Fundação de Amparo à Pesquisa do Estado de São Paulo, Brazil.
Pesquisadora-Conferencista do CNPq (TC 308-Proc. 9051/70). 相似文献
Acknowledgments. The authors wish to express their thanks to Mrs.Arlene Mayhugh for her valuable technical assistance. This work was, in part, supported by grants from the Fundação de Amparo à Pesquisa do Estado de São Paulo, Brazil.
Pesquisadora-Conferencista do CNPq (TC 308-Proc. 9051/70). 相似文献
57.
Bootstrap in time series models is not straightforward to implement, as in this case the observations are not independent. One of the alternatives is to bootstrap the residuals in order to obtain the bootstrap series and thus use these series for inference purposes. This work deals with the problem of assessing the accuracy of hyperparameters in structural models. We study the simplest case, the local level model, where the hyperparameters are given by the variances of the disturbance terms. As their distribution is not known, we employ the bootstrap to approximate the true distribution, using parametric and non‐parametric approaches. Bootstrap standard deviations are computed and their performances compared to the asymptotic and empirical standard errors, calculated using a Monte Carlo simulation. We also build confidence intervals to the hyperparameters, using four bootstrap methods and the results are compared by means of the length, shape and coverage probabilities of the intervals. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献