The Presidency and the Executive Branch in Latin America: What We Know and What We Need to Know

The presidential politics literature depicts presidents either as all- powerful actors or figureheads and seeks to explain outcomes accordingly. Th e president and the executive branch are nonetheless usually treated as black boxes, particularly i n developing countries, even though the presidency has evolved into an extremely complex branch of government. While these developments have been studied in the U nited States, far less i s known in other countries, particularly in Latin America, where presi dential systems have been considered the source of all goods and evils. To help close the knowledge gap and explore differences in policymaking characteristics not only between Latin America and the US but also across Latin American countries, this paper s ummarizes the vast literature on the organization and resources of the Executive Branch in the Americas and sets a research agenda for the study of Latin American presidencies.Fil: Bonvecchi, Alejandro. Universidad Torcuato Di Tella. Departamento de Ciencia Política y Estudios Internacionales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Scartascini, Juan Carlos. Banco Interamericano de Desarrollo; Estados Unido

Cephalexin loading and controlled release studies on mesoporous silica functionalized with amino groups

KIT-6 mesoporous silica has been synthesized using the sol-gel method and functionalized with 3-aminopropyl triethoxysilane by grafting route to obtain KIT-6/NH2. These samples were used as carriers in the loading and controlled release of cephalexin (CFX). The effect of temperature and gastric and intestinal pH on the stability of pure CFX and loaded in KIT-6 and KIT-6/NH2 were investigated. The properties of the synthesized materials and their CFX loading capacity were studied through FTIR, ads-des N2 at 77 K, TEM, SEM, XPS, and TGA. The controlled release tests were carried out in a simulated physiological medium at gastric (1.2) and intestinal pH (6.8). Furthermore, the biocompatibility of both materials was studied through cell viability tests in Caco-2 intestinal cells. The results revealed that KIT-6 and KIT-6/NH2 had similar CFX loading capacities. It was found that CFX degrades at pH 6.8, however, KIT-6 and KIT-6/NH2 were able to protect it from the aforemen-tioned degradation. Moreover, KIT-6 materials presented a good performance as CFX carriers since both mate-rials provided diffusion-controlled release profiles during 24 h, satisfying the Korsmeyer-Peppas kinetic model. Mesoporous silicas presented in this work are promising candidates to be used in CFX controlled release systems due to their chemical interactions, textural properties, and high cell viability

Open borders in the nineteenth century : constructing the national, the citizen and the foreigner in South America

This working paper describes and explains the historical origins of the division between the national and the foreigner in South America. In the early nineteenth century, all the previously Spanish possessions in South America as well as Brazil achieved independence. With this new freedom, countries turned their attention to asserting their statehood through the delineation of three constitutive elements: government, territory and population. The new governments had to define who were going to be considered as nationals, citizens and foreigners, and the rights that pertained to each of these categories. These countries were all concerned with attracting new settlers and very early on introduced constitutional provisions on open borders and equal treatment for foreigners. White, male Europeans were the principal addresses of open borders provisions in an effort to entice them to settle in territories presented as empty to the exclusion of indigenous groups, bring new industries, and contribute to the whitening of mixed race populations. Whilst weak statehood came with independence, forming nations was a much longer process and States used migration and citizenship policies as tools to define nationhood