Opportunities and threats in the beer-banana value chain in Central Uganda

Poster presented at CIALCA Conference 2011. Kigali (Rwanda). 24-27 Oct 2011

Distribution of lipids in non-lamellar phases of their mixtures

We consider a model of lipids in which a head group, characterized by its volume, is attached to two flexible tails of equal length. The phase diagram of the anhydrous lipid is obtained within self-consistent field theory, and displays, as a function of lipid architecture, a progression of phases: body-centered cubic, hexagonal, gyroid, and lamellar. We then examine mixtures of an inverted hexagonal forming lipid and a lamellar forming lipid. As the volume fractions of the two lipids vary, we find that inverted hexagonal, gyroid, or lamellar phases are formed. We demonstrate that the non-lamellar forming lipid is found preferentially at locations which are difficult for the lipid tails to reach. Variations in the volume fraction of each type of lipid tail are on the order of one to ten per cent within regions dominated by the tails. We also show that the variation in volume fraction is correlated qualitatively with the variation in mean curvature of the head-tail interface.Comment: 10 pages, 12 figures (better figures are available upon request), to appear in J. Chem. Phy

Economic gain and other losses? Gender relations and matooke production in Western Uganda

Over the past decades cooking-banana (Matooke) has become increasingly important as food and especially as cash crop for farm households in Isingiro district in the western region of Uganda. High urban and regional demand for Matooke and dwindling Matooke productivity in other areas, drove expanded banana production and more intensive mana- gement. We hypothesised that the increased focus on Matooke by households in Isingiro, affected women and men both as individuals and as household members and affected gender norms on what constitutes a good wife or husband. Qualitative data from one community in Isingiro district was generated based on six in-depth Focus Group Discussions (FGDs), eight structured individual interviews and one community profile using the GENNOVATE method. Survey data with Matooke producers in Ishingiro (N = 51), FGDs with produ- cers (3) and key-informant interviews (5) from a Matooke value-chain development project (ENDURE) was used to compliment and triangulate findings. Results show that the rapid expansion of Matooke cultivation has brought economic progress to many households and has markedly changed the physical landscape in the area. Ownership of a Matooke planta- tion is now among the most important criteria for determining male status and Matooke plantations are largely controlled by men. The focus of men on Matooke has made it easier for women to grow annual crops which increases their options of earning cash income. Women’s access to land however is decreasing. Land is firmly in hands of men and with increasing land scarcity, they allocate less land, less often to their wives for cultivation. Women frequently rent land to cultivate but this is also becoming more expensive and less available. Although women spend a lot of time working in banana plantations, sales is exclusively controlled by men. Only women in female-headed households control sales from Matooke plantations, also because permanent cultures such as banana are not accepted on rented land. We conclude among others that the division of labour in Matooke production is highly gendered. Women in male-headed households benefit from increased revenue at household level but are limited in their options to engage in individual income-generating activities

Import of cytochrome c into mitochondria

The import of cytochrome c into mitochondria can be resolved into a number of discrete steps. Here we report on the covalent attachment of heme to apocytochrome c by the enzyme cytochrome c heme lyase in mitochondria from Neurospora crassa. A new method was developed to measure directly the linkage of heme to apocytochrome c. This method is independent of conformational changes in the protein accompanying heme attachment. Tryptic peptides of [35S]cysteine-labelled apocytochrome c, and of enzymatically formed holocytochrome c, were resolved by reverse-phase HPLC. The cysteine-containing peptide to which heme was attached eluted later than the corresponding peptide from apocytochrome c and could be quantified by counting 35S radioactivity as a measure of holocytochrome c formation. Using this procedure, the covalent attachment of heme to apocytochrome c, which is dependent on the enzyme cytochrome c heme lyase, could be measured. Activity required heme (as hemin) and could be reversibly inhibited by the analogue deuterohemin. Holocytochrome c formation was stimulated 5–10-fold by NADH > NADPH > glutathione and was independent of a potential across the inner mitochondrial membrane. NADH was not required for the binding of apocytochrome c to mitochondria and was not involved in the reduction of the cysteine thiols prior to heme attachment. Holocytochrome c formation was also dependent on a cytosolic factor that was necessary for the heme attaching step of cytochrome c import. The factor was a heat-stable, protease-insensitive, low-molecular-mass component of unknown function. Cytochrome c heme lyase appeared to be a soluble protein located in the mitochondrial intermembrane space and was distinct from the previously identified apocytochrome c binding protein having a similar location. A model is presented in which the covalent attachment of heme by cytochrome c heme lyase also plays an essential role in the import pathway of cytochrome c

Synthesis and characterization of Na03RhO206H2O - a semiconductor with a weak ferromagnetic component

We have prepared the oxyhydrate Na03RhO206H2O by extracting Na+ cations from NaRhO2 and intercalating water molecules using an aqueous solution of Na2S2O8. Synchrotron X-ray powder diffraction, thermogravimetric analysis (TGA), and energy-dispersive x-ray analysis (EDX) reveal that a non-stoichiometric Na03(H2O)06 network separates layers of edge-sharing RhO6 octahedra containing Rh3+(4d6, S=0) and Rh4+ (4d5, S=1/2). The resistivities of NaRhO2 and Na03RhO206H2O (T < 300) reveal insulating and semi-conducting behavior with activation gaps of 134 meV and 7.8 meV, respectively. Both Na03RhO206H2O and NaRhO2 show paramagnetism at room temperature, however, the sodium-deficient sample exhibits simultaneously a weak but experimentally reproducible ferromagnetic component. Both samples exhibit a temperature-independent Pauli paramagnetism, for NaRhO2 at T > 50 K and for Na03RhO206H2O at T > 25 K. The relative magnitudes of the temperature-independent magnetic susceptibilities, that of the oxide sample being half that of the oxyhydrate, is consistent with a higher density of thermally accessible electron states at the Fermi level in the hydrated sample. At low temperatures the magnetic moments rise sharply, providing evidence of localized and weakl -ordered electronic spins.Comment: 15 fages 5 figures Solid State Communications in prin

Immobilized photocatalyst on stainless steel woven meshes assuring efficient light distribution in a solar reactor

An immobilized TiO₂ photocatalyst with a high specific surface area was prepared on stainless steel woven meshes in order to be used packed in layers for water purification. Immobilization of such a complex shape needs a special coating technique. For this purpose, dip coating and electrophoretic deposition (EPD) techniques were used. The EPD technique gave the TiO₂ coating films a better homogeneity and adhesion, fewer cracks, and a higher ^·OH formation than the dip coating technique. The woven mesh structure packed in layers guaranteed an efficient light-penetration in water treatment reactor. A simple equation model was used to describe the distribution of light through the mesh layers in the presence of absorbing medium (e.g., colored water with humic acids). Maximum three or four coated meshes were enough to harvest the solar UV light from 300 nm to 400 nm with a high penetration efficiency. The separation distance between the mesh layers played an important role in the efficiency of solar light penetration through the coated mesh layers, especially in case of colored water contaminated with high concentrations of humic acid