RESUMO Este estudo investigou o impacto do crescimento econômico sobre as reservas internacionais brasileiras no contexto do Mecanismo de Correção de Erros, utilizando dados do período 1980-2014. os resultados revelam que o crescimento econômico é altamente significativo. A partir da estimativa do nosso modelo, argumentamos que o crescimento econômico e as reservas internacionais têm relação positiva de longo prazo. Error correction estimates validated our model for error correction term is negative and statistically significant. Além disso, nosso modo sugere que o crescimento econômico também tem relação de curto prazo. A velocidade de ajuste é mais de 40%, indicando que o termo de correção de erro corrige o desequilíbrio do ano anterior à taxa de 40,4%.

ABSTRACT This study investigated the impact of economic growth on Brazilian international reserves holdings in the context of Error Correction Mechanism using data over the 1980-2014 period. The results reveal that economic growth is highly significant. From the estimation of our model, we argue that economic growth and international reserves have positive long run relationship. Error correction estimates validated our model for error correction term is negative and statistically significant. Besides, our model suggested that economic growth has short run relationship too. The speed of adjustment is more than 40% which indicated that error correction term corrects previous year disequilibrium at the rate of 40.4%.

A simple and sensitive kinetic spectrophotometric method was developed for the determination of labetalol (LBT) hydrochloride. The method was based on the kinetic investigation of the oxidation of the drug with alkaline potassium permanganate at room temperature (25 ± 1°C). The increase in absorbance of coloured manganate ions was measured at 605 nm. All experimental variables affecting the development of the colour were investigated and optimized. The initial rate and fixed time (at 6 minute) methods were adopted for determining the drug concentration. The calibration graphs were linear in the concentration ranges of 2-14 μg mL-1 and 1-10 μg mL-1, using the initial rate and fixed time methods, respectively. The method was successfully applied to the determination of labetalol in laboratory made tablets and commercial tablets. The results were validated statistically and through recovery studies.

Un método simple y sensible de espectrofotometría cinética se desarrolló para la determinación del clorhidrato de labetalol (LBT). El método se basó en la investigación de la cinética de oxidación de la droga con permanganato de potasio alcalino a temperatura ambiente (25 ± 1°C). El aumento de la absorción de iones de manganato coloridos se midió a 605 nm. Se investigaron y optimizaron todas las variables experimentales que afectan al desarrollo del color. Asimismo, se adoptaron la velocidad inicial y el tiempo fijado (a los 6 minutos) de los métodos para la determinación de la concentración del fármaco. Las curvas de calibración fueron lineales en los intervalos de concentración de 2-14 μg mL-1 y 1-10 μg mL-1, haciendo uso de la velocidad inicial y de los tiempos fijados de los métodos, respectivamente. El método se aplicó con éxito a la determinación en el laboratorio de labetalol realizados en tabletas y tabletas comerciales. Los resultados se validaron estadísticamente y mediante estudios de recuperación.