984 resultados para fourth instar
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We extended the characterization of the DNA puff BhB10-1 gene of Bradysia hygida by showing that, although its mRNA is detected only at the end of the fourth larval instar, BhB10-1 expression is not restricted to the salivary gland, the tissue in which this gene is amplified. Different amounts of BhB10-1 mRNA were detected in other larval tissues such as gut, Malpighian tubules, fat body, brain and cuticle, suggesting that this gene is expressed differentially in the various tissues analyzed. Analysis of transgenic Drosophila carrying the BhB10-1 transcription unit and flanking sequences revealed that the tested fragment promotes transcription in a constitutive manner. We suggest that either cis-regulatory elements are missing in the transgene or factors that temporally regulate the BhB10-1 gene in B. hygida are not conserved in Drosophila.
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Elongation factor 1A is a highly conserved protein that participates in translation. We report the occurrence of two genes homologous to the eukaryotic Elongation Factor 1A in Bradysia hygida and describe the partial cloning and characterization of the B. hygida eukaryotic Elongation Factor 1A-F1 (BheEF1A-F1) gene. The pattern of BheEF1A-F1 expression in the salivary gland at the end of the fourth larval instar was investigated using real-time PCR. The results showed that BheEF1A-F1 expression levels are relatively constant at the time when rapid changes in protein synthesis occur in this tissue. In situ hybridization experiments coupled to Southern blot analyses showed that the BheEF1A-F1 gene is located at position 3d of the A chromosome and a second gene homologous to eEF1A is located at position 6a of the X chromosome. Southern blot analyses showed that both the BheEF1A-F1 gene and the second gene homologous to eEF1A constitute non-amplified genes. The present results contribute to the molecular characterization of a sciarid eEF1A gene.
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We have calculated the thermodynamic properties of monatomic fcc crystals from the high temperature limit of the Helmholtz free energy. This equation of state included the static and vibrational energy components. The latter contribution was calculated to order A4 of perturbation theory, for a range of crystal volumes, in which a nearest neighbour central force model was used. We have calculated the lattice constant, the coefficient of volume expansion, the specific heat at constant volume and at constant pressure, the adiabatic and the isothermal bulk modulus, and the Gruneisen parameter, for two of the rare gas solids, Xe and Kr, and for the fcc metals Cu, Ag, Au, Al, and Pb. The LennardJones and the Morse potential were each used to represent the atomic interactions for the rare gas solids, and only the Morse potential was used for the fcc metals. The thermodynamic properties obtained from the A4 equation of state with the Lennard-Jones potential, seem to be in reasonable agreement with experiment for temperatures up to about threequarters of the melting temperature. However, for the higher temperatures, the results are less than satisfactory. For Xe and Kr, the thermodynamic properties calculated from the A2 equation of state with the Morse potential, are qualitatively similar to the A 2 results obtained with the Lennard-Jones potential, however, the properties obtained from the A4 equation of state are in good agreement with experiment, since the contribution from the A4 terms seem to be small. The lattice contribution to the thermal properties of the fcc metals was calculated from the A4 equation of state, and these results produced a slight improvement over the properties calculated from the A2 equation of state. In order to compare the calculated specific heats and bulk moduli results with experiment~ the electronic contribution to thermal properties was taken into account~ by using the free electron model. We found that the results varied significantly with the value chosen for the number of free electrons per atom.
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Notes by F. L. Olmsted.
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Fourth Annual Report of The Electrical Development Company of Ontario Limited for for the year 1906. The report discusses the main line between Niagara Falls and Toronto and the line between the Township of Pelham and the city of Brantford. The report also details the purchase of stocks and bonds in several different companies.
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A photograph of Dorothy Rungeling's fourth airplane, a 1956 Cessna 172, 4 seat 145 Continental engine. She is sitting in pilot position.
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A report for 1 April 1969 to 31 March 1970 by the Liquor Control Board of Ontario. The report consists of following: Sales, Winers, Personnel, Stores, Permits, and Financial Statements.
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UANL
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UANL
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Over-sampling sigma-delta analogue-to-digital converters (ADCs) are one of the key building blocks of state of the art wireless transceivers. In the sigma-delta modulator design the scaling coefficients determine the overall signal-to-noise ratio. Therefore, selecting the optimum value of the coefficient is very important. To this end, this paper addresses the design of a fourthorder multi-bit sigma-delta modulator for Wireless Local Area Networks (WLAN) receiver with feed-forward path and the optimum coefficients are selected using genetic algorithm (GA)- based search method. In particular, the proposed converter makes use of low-distortion swing suppression SDM architecture which is highly suitable for low oversampling ratios to attain high linearity over a wide bandwidth. The focus of this paper is the identification of the best coefficients suitable for the proposed topology as well as the optimization of a set of system parameters in order to achieve the desired signal-to-noise ratio. GA-based search engine is a stochastic search method which can find the optimum solution within the given constraints.
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Resumen tomado de la publicación