Compensation Phenomenon
Mostrando 13-21 de 21 artigos, teses e dissertações.
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13. Regulation of Gene Activity by Dosage Compensation at the Chromosomal Level in Drosophila
Two models of dosage compensation have been tested by the measurement of G6PD and 6PGD enzymatic specific activities in flies hyperploid for regions of the X chromosome. Females duplicated for the proximal half of the X chromosome (2½ X's) have an increased level of G6PD and a normal level of 6PGD. Females duplicated for the distal half of the X chromosome
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14. Interference Competition and Niche Theory
A linear model of interspecific competition with separate parameters for exploitation and interference is deduced. Interference is assumed to have a cost and an effect. The interfering species realizes a “profit” if some resources, which the species interfered against would have utilized, are made available as a result of the interference. Interference i
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15. Mutation frequency and biological cost of antibiotic resistance in Helicobacter pylori
Among the several factors that affect the appearance and spread of acquired antibiotic resistance, the mutation frequency and the biological cost of resistance are of special importance. Measurements of the mutation frequency to rifampicin resistance in Helicobacter pylori strains isolated from dyspeptic patients showed that ≈1/4 of the isolates had h
The National Academy of Sciences.
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16. Vibration injuries in Norwegian forest workers
Hellstr⊘m, B., and Lange Andersen, K. (1972).Brit. J. industr. Med.,29, 255-263. Vibration injuries in Norwegian forest workers. A free medical examination with compensation for lost earnings was offered to the forest workers in three areas of eastern Norway. Sixty-six per cent attended (413 workers, of whom 296 used chain saws). The prevalence of Raynaud'
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17. Genetic Analysis of the 5s RNA Genes in DROSOPHILA MELANOGASTER
The 5S RNA genes of Drosophila melanogaster in either an isogenic wild-type or a multiply inverted (SM1) chromosome 2 increase their multiplicity when opposite a deficiency for the 5S gene site. This is analogous to the compensation phenomenon previously described for the 18S and 28S ribosomal RNA genes of the X chromosome nucleolus organizer region. Molecu
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18. Modulation of Protein Levels in Chromosomal Dosage Series of Maize: The Biochemical Basis of Aneuploid Syndromes
Genetically defined dosage series of chromosome arms 1L, 3L, 4S, 5L, 7L, 9S, 10L and combinations of 1L–3L, collectively spanning approximately one-third of the maize genome, were examined for alterations in the expression of total protein profiles in scutellar tissue. The major effects found were negative correlations of specific proteins with the dosage
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19. Toward an estimation of binding constants in aqueous solution: studies of associations of vancomycin group antibiotics.
An approach toward the estimation of binding constants for organic molecules in aqueous solution is presented, based upon a partitioning of the free energy of binding. Consideration is given to polar and hydrophobic contributions and to the entropic cost of rotor restrictions and bimolecular associations. Several parameters (derived from an analysis of entro
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20. Respiratory effects of lowering tar and nicotine levels of cigarettes smoked by young male middle tar smokers. II. Results of a randomised controlled trial.
STUDY OBJECTIVE--The aim was to investigate the effect on respiratory health of male middle tar smokers changing the tar and nicotine levels of the cigarettes they smoke for a six month period. DESIGN--This was a randomised controlled trial. Middle tar smokers were randomly allocated to smoke one of three different types of cigarette (low tar, middle nicotin
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21. Serum endothelin concentrations in workers exposed to vibration.
OBJECTIVES: Endothelin 1 (ET1) is one of a newly discovered family of potent naturally occurring vasoconstrictors produced by the endothelium. A few publications indicated that the peptide may have a role in idiopathic Raynaud's phenomenon and Raynaud's phenomenon secondary to connective tissue disease. The aim of this study was to compare serum endothelin c