A Decade of Changes in the Transportation of Passengers： What Are the Factors That Affected the Demand？

Ten years of financial stability in Brazilian economy have gone. In this period, the regional transportation of passengers suffered exogenous impacts： economical crises, airport crises and great proportions＇ accidents, as well as impacts which were intern to the system： institutional changes （liberation of tariff promotions, many companies establishing themselves and also coming to bankruptcy）, creation of regulating institutions in the air transportation as well as the land transportation. Theoretically, it is expected that these changes have generated impacts in the demand for trips, since an environment regulated with more flexible prices and higher amounts of companies would generate a competitive environment in which the companies could struggle to attract their demand. On the other hand, the impacts which are exogenous to the system can generate responses in the sense of restoring the balance of demand. Thus, based on the theoretical experience, this article aims at analyzing empirically, through categorical variables, if there were impacts on the demand for regional trips in Brazil due to the internal or external changes. In order to perform this, monthly data from January, 1999 to December, 2009 are utilized and estimates are calculated making use of SUR （seemingly unrelated regressions）. As a result, we have the meaning of the internal and external impacts related to air and land transports, identifying that the worldwide economic crisis generated an impact at the level of the demand for transportation and also that the flexibility of tariffs allowed by ANTT （Ag^ncia Nacional de Transportes Terrestres） had an equal impact on the demand for land transportation.

<i>Schistosoma mansoni</i>: Phytochemical Effect on Aquatic Life Cycle

Background: Two aspects need to be considered for schistosomiasis control: morbidity and transmission. In this context, many soluble substances have been tested and Euphorbia milii latex is one of the most promising Brazilian molluscicides. Phytochemical studies involving simulation of the applicability of this latex on all aquatic forms of the S. mansoni life cycle are rare in the literature. The aim of this work was to evaluate the effect of E. milii latex on S. mansoni in the egg, miracidium and different developmental stages in Biomphalaria glabrata. Methods: The laboratory study was designed to simulate the different forms of exposure of the life cycle stages of S. mansoni to the LC50 of E. milii latex;we tested the exposition from four situations of S. mansoni contact with the latex and observed the exposure on different snails’ infection stage too. All snails were analyzed weekly for cercarial shedding and reproductive biology. Results: The results showed that contact of S. mansoni eggs and miracidia with the LC50 of E. milii negatively influenced the development of the parasite life cycle in the intermediate host, with consequent reduction of cercarial shedding. The exposure of infected snails affected the reproductive biology and cercarial shedding in all intra-mollusk development stages of S. mansoni, but the reduction was greater in the first, fourth, fifth, sixth, seventh and eighth weeks of infection. The LC50 of E. milii latex had toxic action on eggs and miracidia, and the number of cercariae shed by snails during the study period declined by about 80%. Conclusions: We can conclude that the use of natural biodegradable compounds containing low concentrations of substances already characterized as having eco-toxico- logical potential can be an important tool to reduce the transmission of Schistosomiasis.