Content And Nature Of Carbon
Mostrando 13-24 de 30 artigos, teses e dissertações.
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13. Termodecomposição, estudos de carbonização e silicificação da matéria orgânica e corpos silicosos em ecossistemas terrestres no Brasil e na Antártica / Thermodecomposition, organic matter carbonization silicification studies and silica bodies in terrestrial ecosystems in Brazil and Antarctica
Soil organic matter (SOM) is highly heterogeneous in composition, which consists of components as different from each other as labile carbohydrates and recalcitrant aliphatic compounds. Mean residence time (MRT) of the various compounds comprising soil organic matter may range from a few minutes to thousands of years. This wide range is partly due to the soi
Publicado em: 2007
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14. Chemical and spectroscopic characterization of organic matter in Brazilian soils / Caracterização química e espectroscópica da matéria orgânica em solos do Brasil
The importance on the study of organic matter in pedology and soil classification studies in tropical regions can be substantiated by the differential attributes: organic carbon content, degree of organic matter decomposition, and fibers content. However, quantitative and qualitative variables such as chemical fractionating of organic matter and spectroscopi
Publicado em: 2006
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15. The influence of soil characteristics in remediation of contaminated soils through advanced oxidation process with Sodium Persulfate and Fenton Reagent. / A influência das características dos solos na remediação de solos contaminados através de processos oxidativos avançados com persulfato e reagente de fenton
The remediation techniques used in contaminated soils such as "in situ" chemical oxidation aim essentially the mineralization of contaminants, reducing it to CO2 and H2O. The objective of this study is pointing out the results of experiments conducted to investigate how the soil characteristics such as granulometry, assay and nature of clay minerals as well
Publicado em: 2006
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16. Produtividade de biomassa e interaÃÃes Ãrvore-cultivo em sistemas agroflorestais no Agreste da ParaÃba
Agroforestry systems, such as alley cropping or the implantation of glricidia hedgerows (Gliricidia sepium), are being adopted in agricultural family properties in the rural area of ParaÃba with the objetective of bettering soil fertility and increasing cattle breeding productivity. However, studies regarding the dynamics of nutrients, water and biomass pro
Publicado em: 2006
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17. THE UNEXTRACTABLE ORGANIC FRACTION OF THE PUEBLITO DE ALLENDE METEORITE: EVIDENCE FOR ITS INDIGENOUS NATURE*
The Pueblito de Allende meteorite contains only 0.1-0.5 ppm of solvent-extractable carbon, most or all of which is due to terrestrial contamination. Determinations of the total carbon content gives values from 0.23 to 0.35 per cent. The presumed indigenous insoluble carbon is thus present in a ratio of 2300:1 relative to contaminant carbon. A sample of the m
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18. Effects of carbon source and growth rate on cell wall composition of Bacillus subtilis subsp. niger.
A study was made to determine whether factors other than the availability of phosphorus were involved in the regulation of synthesis of teichoic and teichuronic acids in Bacillus subtilis subsp. niger WM. First, the nature of the carbon source was varied while the dilution rate was maintained at about 0.3 h-1. Irrespective of whether the carbon source was gl
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19. Barbiturate blood levels found at necropsy in proven cases of acute barbiturate poisoning
In order to determine whether blood barbiturate levels could be used to ascertain that death had been caused by barbiturate overdose, samples of blood from 128 subjects of coroners' necropsies were examined for barbiturate content. Sixty of these were well authenticated cases of barbiturate overdosage, and barbiturates were implicated, together with other fa
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20. Lipid Synthesis by Isolated Chlamydia psittaci
The isolated cells of the host-dependent meningopneumonitis agent, Chlamydia psittaci, were shown to incorporate radioactive carbon from aspartate, isoleucine, and glucose-6-phosphate into cell lipids. The nature of this incorporation was investigated. Radioactivity was found only in the fatty acids and primarily in the phosphatidyl ethanolamine, and, to a l
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21. Effect of R-plasmid RP1 and nutrient depletion on the gross cellular composition of Escherichia coli and its resistance to some uncoupling phenols.
The resistance of Escherichia coli batch cultures depleted of carbon (C-dep), magnesium (Mg-dep), or phosphate (P-dep) against low concentrations of 3-chlorophenol, 4-chlorophenol, or 2-phenoxyethanol varied. C-dep cultures were always significantly more sensitive than Mg-dep or P-dep cultures. The presence of R-plasmid RP1 increased the sensitivity of C-dep
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22. Phagocytic potential of pulmonary alveolar epithelium with particular reference to surfactant metabolism
Finely divided thorium and carbon were injected into the rat lung via the trachea and their uptake was studied electron microscopically. Small amounts of thorium were found in the lamellar vacuoles of the granular pneumocytes. Their presence was maximal at 24 hours and they later disappeared from these cells. This phenomenon is thought to represent a passive
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23. Effect of Carbon Source on Size and Associated Properties of Bacillus megaterium Spores
The size of the spores produced by Bacillus megaterium ATCC 19213 depended upon the nature of the carbon source present in the defined medium in which they were produced. Homogeneous preparations of small (0.38 μm3), nearly spherical spores were produced after batch culture in the presence of 2.8 mm citrate, and large (1.17 μm3), oblong spores were produce
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24. Interaction of Z form poly(dG-dC).poly(dG-dC) with divalent metal ions: localization of the binding sites by I.R. spectroscopy.
The secondary structures of poly(dG-dC).poly(dG-dC) in the presence of alcaline , alcaline earth and first row transition metal ions (Na+, Mg2+, Co2+, Ni2+) are investigated by infrared spectroscopy. The conformational transitions are studied as a function of the hydration of the polynucleotide and counter-ion nature and content. The use of selectively deute