Apertura comercial y cambio tecnológico en el Istmo Centroamericano

Incluye Bibliografía

O papel das argininas alfa-92 e alfa-141 na regulação das propriedades funcionais de hemoglobinas por íons cloreto

The oxygenation of human Hb (HbA) demands a three state model: two deoxy states To and Tx, free and complexed with anions respectively, and an oxy R state. The regulation between these states is modulated by the presence of anions, such as chloride, that binds to T state. The b inding if chloride, however, remains controversial. The aim of this work is the study of arginines 92a (a1ß2 interface) and 141a (C-terminal) as chloride binding sites. To investigate that, we have studied 92 and 141 site directed mutant species: natural mutants Hb J-Cape-Town (R92Q), desArg (R141Δ), Chesapeake (R92L), and the constructed Chesapeake desArg (R92L,141Δ). We expressed Hbs in Escherichia coli and purified. Through oxygen binding curves we measured affinity and cooperativity, in function of water effect and Bohr effect in presence and absence of chloride. Structural features were obtained through 1H NMR spectroscopy Oxygen binding properties and Bohr effect measured indicated a higher affinity and lower cooperativity in absence and presence of chloride for all mutants. Structural changes represent functional aspects of mutant Hbs, such as a significant rise in affinity or a change in cooperativity. Water activity studies conducted as a function of chloride concentration showed that the only Hb desArg follows the thre state model. The other mutant Hbs do not exhibit the Tx state, a fact confirmed by the number of water molecules bound to each Hb during the deoxy-oxy transition. This behavior suggests that the Arginine 92 site could be responsible for chloride binding to Hb, since oxygenation of 92 mutant Hbs cannot be adjusted by the three state model. However, Bohr effect showed that all mutant Hbs released~1 proton in chloride presence, different from HbA that releases ~2, suggesting a role for 141 arginine in the tertiary and quaternary Bohr effect.

Patrones de especialización comercial y desempeño del mercado de trabajo en América Latina

Incluye Bibliografía

Imprensa, política e publicidade: Um estudo sobre a revista Caros Amigos (1997-2006)

The article discusses the relationship between media, politics and advertising in the magazine Caros Amigos between 1997 and 2006. It studies on the weight of the Partido dos Trabalhadores in the funding of the publication and the charges made against the magazine's publishers due to this fact. © 2011 by Unisinos.

Bienes y servicios ambientales en México: caracterización preliminar y sinergias entre protección ambiental, desarrollo del mercado y estrategia comercial

Incluye Bibliografía

El dumping social": la política social como política comercial"

Incluye Bibliografía

Inversión y productividad en el sector agrícola-agroindustrial boliviano: caso de la agricultura comercial período 1985-1998

Incluye Bibliografía

Propagação in vitro de Cattleya trianaei (Linden & Reichenbach fil.) (Orchidaceae) em meios de culturas e com doses de fertilizante comercial

The use of culture media produced with commercial fertilizers can represent a simple and low cost alternative for commercial orchid propagation. The aim of this study was to evaluate the in vitro growth of plantlets of Cattleya trianaei in culture medium MS reduced and and formulated with Peters® NPK 10-30-20 in different doses. 90 day-old plantlets with two leaflets were submitted to five treatments (T1 - reduced MS; T2 - Peters® 1 g L -1; T3 - Peters® 2 g L-1; T4 - Peters® 3 g L -1 and T5 - Peters® 5 g L-1) arranged in a completely randomized design with five replicates with 25 plantlets for each treatment and incubated during 180 days, with subcultures at each 60 days, when the number of roots, root length, number of leaves, shoot length and shoot fresh matter were evaluated. The simplified culture medium with fertilizer Peters® 3 g L -1 presented results statistically different as for the number of roots, number of leaves, shoot length and shoot fresh matter and it can be recommended for in vitro growth of this ornamental orchid.

Economía y economía política de la reforma comercial colombiana

Incluye Bibliografía

La reforma del régimen comercial en México durante los años ochenta: sus efectos económicos y dimensiones políticas

Incluye Bibliografía

Economía política de la apertura comercial chilena

Incluye Bibliografía

Algunas consideraciones sobre las formas de medir el fraude comercial externo en Argentina

Incluye Bibliografía

Política comercial y equidad

Incluye Bibliografía

El impacto de la política cambiaria y comercial en el desempeño exportador en los años ochenta: una revisión de estudios econométricos

Incluye Bibliografía

Comercio exterior y la política comercial en los países del Caribe de habla inglesa = Foreign trade and trade policy of the English-speaking Caribbean countries

Incluye Bibliografía