Coal supply situation: availability for substitution in the Kenyan economy

This paper analyses the coal/supply situation as it pertains to the availability for substitution in Kenya. It is a part of a study, Coal/Fuel Oil Substitution Potentials in the Kenyan Economy which, in nutshell, investigates the substitution potentials in the Kenyan Economy and further assesses the implications of such potentials to both dependence on imported crude oil and the capability of the economy to adjust in light of two envisaged developments. The first development is the changing quality of the bulk of crude oil on which Kenya depends. The second is the increasing demand for superior products which is expected to evolve, both in absolute and relative terms, as the economy grows. The potential for these developments to affect the fuel oil supply is high. If the effect is negative, the issue of substitution becomes necessarily a vital policy consideration. Coal is, by and large, seen as an immediate option. Accordingly at all levels of policy consideration, the availability of coal as a substitute must be conceived, at least, as probable. The paper underscores two basic supply conditions. The first is the mineral nature of coal commodity. And, the second is the dependence on imported coal which theoretically can be procured from any outside source. It has been, therefore, necessary to establish the basic mineral supply concepts and approach the Kenyan coal availability from global supply framework. With these as the background the paper analyses the world supply situation and from this extrapolates to put the Kenyan supply situation into relevant perspectives. In this task the fuel oil and coal consumptions in Kenya are reviewed and analysed in order to identify energy gaps and coal consumption potentials. The conclusion is that, by and large, availability potentials are high to a degree where Kenya would be capable of diversifying the supply source not only to meet her coal requirements but also to ensure a reasonable degree of supply security

A Randomized Controlled Phase Ib Trial of the Malaria Vaccine Candidate GMZ2 in African Children

BACKGROUND: GMZ2 is a fusion protein of Plasmodium falciparum merozoite surface protein 3 (MSP3) and glutamate rich protein (GLURP) that mediates an immune response against the blood stage of the parasite. Two previous phase I clinical trials, one in naïve European adults and one in malaria-exposed Gabonese adults showed that GMZ2 was well tolerated and immunogenic. Here, we present data on safety and immunogenicity of GMZ2 in one to five year old Gabonese children, a target population for future malaria vaccine efficacy trials. METHODOLOGY/PRINCIPAL FINDINGS: Thirty children one to five years of age were randomized to receive three doses of either 30 µg or 100 µg of GMZ2, or rabies vaccine. GMZ2, adjuvanted in aluminum hydroxide, was administered on Days 0, 28 and 56. All participants received a full course of their respective vaccination and were followed up for one year. Both 30 µg and 100 µg GMZ2 vaccine doses were well tolerated and induced antibodies and memory B-cells against GMZ2 as well as its antigenic constituents MSP3 and GLURP. After three doses of vaccine, the geometric mean concentration of antibodies to GMZ2 was 19-fold (95%CI: 11,34) higher in the 30 µg GMZ2 group than in the rabies vaccine controls, and 16-fold (7,36) higher in the 100 µg GMZ2 group than the rabies group. Geometric mean concentration of antibodies to MSP3 was 2.7-fold (1.6,4.6) higher in the 30 µg group than in the rabies group and 3.8-fold (1.5,9.6) higher in the 100 µg group. Memory B-cells against GMZ2 developed in both GMZ2 vaccinated groups. CONCLUSIONS/SIGNIFICANCE: Both 30 µg as well as 100 µg intramuscular GMZ2 are immunogenic, well tolerated, and safe in young, malaria-exposed Gabonese children. This result confirms previous findings in naïve and malaria-exposed adults and supports further clinical development of GMZ2. TRIAL REGISTRATION: ClinicalTrials.gov NCT00703066

Plant-mediated effects on mosquito capacity to transmit human malaria

The ecological context in which mosquitoes and malaria parasites interact has received little attention, compared to the genetic and molecular aspects of malaria transmission. Plant nectar and fruits are important for the nutritional ecology of malaria vectors, but how the natural diversity of plant-derived sugar sources affects mosquito competence for malaria parasites is unclear. To test this, we infected Anopheles coluzzi, an important African malaria vector, with sympatric field isolates of Plasmodium falciparum, using direct membrane feeding assays. Through a series of experiments, we then examined the effects of sugar meals from Thevetia neriifolia and Barleria lupilina cuttings that included flowers, and fruit from Lannea microcarpa and Mangifera indica on parasite and mosquito traits that are key for determining the intensity of malaria transmission. We found that the source of plant sugar meal differentially affected infection prevalence and intensity, the development duration of the parasites, as well as the survival and fecundity of the vector. These effects are likely the result of complex interactions between toxic secondary metabolites and the nutritional quality of the plant sugar source, as well as of host resource availability and parasite growth. Using an epidemiological model, we show that plant sugar source can be a significant driver of malaria transmission dynamics, with some plant species exhibiting either transmission-reducing or -enhancing activities