11 resultados para exchange value

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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A tese do fim das metanarrativas defendida pelo pós-modernismo implica a negação da universalidade da cultura. Não se trata apenas do fato de que a cultura humana ainda não tenha alcançado um estágio de verdadeira universalidade nem mesmo se trata do fato de que a classe dominante tenha até hoje submetido a cultura humana a seus interesses particulares de classe e, para tanto, tenha sufocado e destruído muito da riqueza contida nas culturas locais. Para o pós-modernismo, o problema não reside na visão burguesa de cultura humana, mas sim na própria idéia de que possa haver uma cultura universal. Os pós-modernos afirmam que qualquer projeto educacional pautado na idéia da existência ou da possibilidade de uma cultura universal é um projeto conservador, autoritário e etnocêntrico. O texto defende a tese de que a concepção marxiana acerca do processo histórico de constituição da riqueza humana universal contém os elementos teóricos necessários para a superação da falsa opção, postulada pelas diversas correntes do pós-modernismo, entre o etnocentrismo e o relativismo cultural. em Marx, a universalização da cultura humana ocorre, na sociedade capitalista, por meio da universalização do valor de troca das mercadorias como mediação fundamental das relações sociais. Trata-se, portanto, de um processo dialético no qual ocorrem ao mesmo tempo a humanização e a alienação do gênero humano e dos indivíduos. O texto conclui com a apresentação dos desafios que, a partir dessa concepção marxiana sobre a riqueza universal, devem ser enfrentados no processo de construção de uma pedagogia marxista.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The present work discuss the reproduction of the social relations from the point of view of the new urban production relations - having as empirical universe for analysis-, the Itaquera district in the Sao Paulo metropolis, with the advent of the World Cup in Brazil. Starting with the reading of a reality in movement, in which the analysis walks covering the dialectic relationship between space and society, where the first is translated into product and life reproduction condition, aiming to unveil the metamorphoses that will take place in the urban space with its consequent contradiction, what it may be the expanded capital reproduction concomitantly with the process that denounces a spoliation movement of the social space. With the society approval before these big architectural projects enabled by ideology, it’s determined the (re) production of artificial spaces of consumption, funded for the capital extension. The current stage that the capitalism reveals a space turned into mass consumption merchandise, consequence of the victory of the exchange value over the usage value, amalgamated in positive measures of expulsion/sweeping of low income socio-economic layers

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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A flow-injection system with a Chelite-S® cationic resin packed minicolumn is proposed for the determination of trace levels of mercury in agroindustrial samples by cold vapor atomic absorption spectrometry. Improved sensitivity and selectivity are attained since mercuric ions are on-line concentrated whereas other potential interferents are discarded. With on-line reductive elution procedure, concentrated hydrochloric acid could be replaced by 10% w/v SnCl2, in 6 M HCl as eluent. The reversed-intermittent stream either carries the atomic mercury, to the flow cell in the forward direction or removes the residue from reactor/gas liquid separator to a discarding flask in the opposite direction. Concentration and volume of reagent, acidity, flow rates, commutation times and potential interfering species were investigated. For 120 s preconcentration time, the proposed system handles about 25 samples h-1 (50.0 500 ng l-1), consuming about 10 ml sample and 5 mg SnCl2 per determination. The detection limit is 0.8 ng l-1 and the relative standard deviation (RSD) (n = 12) of a 76.7 ng l-1 sample is about 5%. Results are in agreement with certified value of standard materials at 95% confidence level and good recoveries (97-128%) of spiked samples were found. (C) 2000 Elsevier Science B.V.

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A new strategy for minimization of Cu2+ and Pb2+ interferences on the spectrophotometric determination of Cd2+ by the Malachite green (MG)-iodide reaction using electrolytic deposition of interfering species and solid phase extraction of Cd2+ in flow system is proposed. The electrolytic cell comprises two coiled Pt electrodes concentrically assembled. When the sample solution is electrolyzed in a mixed solution containing 5% (v/v) HNO3, 0.1% (v/v) H2SO4 and 0.5 M NaCl, Cu2+ is deposited as Cu on the cathode, Pb2+ is deposited as PbO2 on the anode while Cd2+ is kept in solution. After electrolysis, the remaining solution passes through an AG1-X8 resin (chloride form) packed minicolumn in which Cd2+ is extracted as CdCl4/2-. Electrolyte compositions, flow rates, timing, applied current, and electrolysis time was investigated. With 60 s electrolysis time, 0.25 A applied current, Pb2+ and Cu2+ levels up to 50 and 250 mg 1-1, respectively, can be tolerated without interference. For 90 s resin loading time, a linear relationship between absorbance and analyte concentration in the 5.00-50.0 μg Cd 1-1 range (r2 = 0.9996) is obtained. A throughput of 20 samples per h is achieved, corresponding to about 0.7 mg MG and 500 mg KI and 5 ml sample consumed per determination. The detection limit is 0.23 μg Cd 1-1. The accuracy was checked for cadmium determination in standard reference materials, vegetables and tap water. Results were in agreement with certified values of standard reference materials and with those obtained by graphite furnace atomic absorption spectrometry at 95% confidence level. The R.S.D. for plant digests and water containing 13.0 μg Cd 1-1 was 3.85% (n = 12). The recoveries of analyte spikes added to the water and vegetable samples ranged from 94 to 104%. (C) 2000 Elsevier Science B.V.

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The local concentrations of chloride, Cl b, and bromide, Br b, in the interface of vesicles prepared with dioctadecyldimethylammonium chloride, DODAC, or bromide, DODAB, dipalmitoylphosphatidylcholine, DPPC, dimyristoylphosphatidylcholine, DMPC, and mixtures of DMPC, DPPC, and DODAC were determined by chemical trapping by analyzing product yields from spontaneous dediazoniation of vesicle-bound 2,6-dimethyl-4-hexadecylbenzenediazonium ion. The values of Cl b and Br b in DODAC and DODAB vesicles increase with vesicle size, in agreement with previous data showing that counterion dissociation decreases with vesicle size. Addition of tetramethylammonium chloride displaces bromide from the DODAB vesicular interface. The value for the selectivity constant for Br/Cl exchange at the DODAB vesicular interface obtained by chemical trapping was ∼2.0, well within values obtained for comparable amphiphiles. In vesicles of DPPC the values of Cl b were very sensitive to the nature of the cation and decreased in the order Ca 2+ > Mg 2+ > Li + > Na + > K + = Cs + = Rb + ≥ +. The effect of the cation becomes more important as temperature increases above the phase transition temperature, T m, of the lipid. The values of Cl b increased sigmoidally with the mol % of DODAC in vesicles prepared with DODAC/lipid mixtures. In sonicated vesicles prepared with DODAC and DMPC (or DPPC), the values of Cl b reach local concentrations measured for the pure amphiphile at 80 mol % DODAC. These results represent the first extensive study of local concentration of ions determined directly by chemical trapping in vesicles prepared with lipids, synthetic ampliiphiles, and their mixtures.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)