Integrating participatory community mobilization processes to improve dengue prevention: an eco-bio-social scaling up of local success in Machala, Ecuador

This project investigates the effectiveness and feasibility of scaling-up an eco-bio-social approach for implementing an integrated community-based approach for dengue prevention in comparison with existing insecticide-based and emerging biolarvicide-based programs in an endemic setting in Machala, Ecuador.

Displacement of Zn through acidic light-textured soils

In order to gain understanding of the movement of pollutant metals in soil. the chemical mechanisms involved in the transport of zinc were studied. The displacement of zinc through mixtures of sand and cation exchange resin was measured to validate the methods used for soil. With cation exchange capacities of 2.5 and 5.0 cmol(c) kg(-1). 5.6 and 8.4 pore volumes of 10 mM CaCl2, respectively, were required to displace a pulse of ZnCl2. A simple Burns-type model (Wineglass) using an adsorption coefficient (K-d) determined by fitting a straight line relationship to an adsorption isotherm gave a good fit to the data (K-d=0.73 and 1.29 ml g(-1), respectively). Surface and subsurface samples of an acidic sandy loam (organic matter 4.7 and 1.0%. cation exchange capacity (CEC) 11.8 and 6.1 cmol(c) kg(-1) respectively) were leached with 10 mM calcium chloride. nitrate and perchlorate. With chloride. the zinc pulse was displaced after 25 and 5 pore volumes, respectively. The Kd values were 6.1 and 2.0 ml g(-1). but are based on linear relationships fitted to isotherms which are both curved and show hysteresis. Thus. a simple model has limited value although it does give a general indication of rate of displacement. Leaching with chloride and perchlorate gave similar displacement and Kd values, but slower movement occurred with nitrate in both soil samples (35 and 7 pore volumes, respectively) which reflected higher Kd values when the isotherms were measured using this anion (7.7 and 2.8 ml g(-1) respectively). Although pH values were a little hi-her with nitrate in the leachates, the differences were insufficient to suggest that this increased the CEC enough to cause the delay. No increases in pH occurred with nitrate in the isotherm experiments. Geochem was used to calculate the proportions of Zn complexed with the three anions and with fulvic acid determined from measurements of dissolved organic matter. In all cases, more than 91% of the Zn was present as Zn2+ and there were only minor differences between the anions. Thus, there is an unexplained factor associated with the greater adsorption of Zn in the presence of nitrate. Because as little as five pore volumes of solution displaced Zn through the subsurface soil, contamination of ground waters may be a hazard where Zn is entering a light-textured soil, particularly where soil salinity is increased. Reductions in organic matter content due to cultivation will increase the hazard. (C) 2004 Elsevier B.V. All rights reserved.

Space physics for graduate students: an activities-based approach

The geospace environment is controlled largely by events on the Sun, such as solar flares and coronal mass ejections, which generate significant geomagnetic and upper atmospheric disturbances. The study of this Sun-Earth system, which has become known as space weather, has both intrinsic scientific interest and practical applications. Adverse conditions in space can damage satellites and disrupt communications, navigation, and electric power grids, as well as endanger astronauts. The Center for Integrated Space Weather Modeling (CISM), a Science and Technology Center (STC) funded by the U.S. National Science Foundation (see http://www.bu.edu/cism/), is developing a suite of integrated physics-based computer models that describe the space environment from the Sun to the Earth for use in both research and operations [Hughes and Hudson, 2004, p. 1241]. To further this mission, advanced education and training programs sponsored by CISM encourage students to view space weather as a system that encompasses the Sun, the solar wind, the magnetosphere, and the ionosphere/thermosphere. This holds especially true for participants in the CISM space weather summer school [Simpson, 2004].