In pursuit of proper contexts for sustainability in rural Africa

Summary Sustainable development is high on development analysts' agendas as people seek viable alternatives to current development concepts. These latter approaches have not satisfied people's livelihoods especially in developing countries. This paper suggests that the promotion of sustainable development must correctly identify the contexts within which it is to be pursued. It is essential to note that this is best done if people recognize that as a complex concept, sustainable development has several dimensions, including the resource base of a country/community/society; external factors impacting on it; internal factors at play within; population factors and political economic factors.For rural Africa, the context is one of small community and kinship based production groups largely dependent on their local environments for survival. It is essential to identify endogenous factors such as local knowledge bases, common property arrangements, other local social institutions and local environmental practices and to base sustainability strategies on these.There is growing awareness of the efficacy of these local indigenous systems but constraints to their promotion as a valuable resource are also significant. There is room for being hopeful that rural Africa might sustain itself if recognition of the correct contexts is sought.Mr Joseph Z.Z. Matowanyika obtained his Bachelor's and Master's Degrees respectively at the Universities of Reading and Nottingham, in the UK. He is currently undertaking research in the Department of Geography of the University of Waterloo for a Doctor of Philosophy.     

Effects of nest site concealment on hatching success,reproductive success,and paternal behavior of the threespine stickleback,Gasterosteus aculeatus

Summary Male sticklebacks (Gasterosteus aculeatus) actively competed for a limited number of clay flowerpots as nest sites in circular wading pools. Males nesting in pots spawned earlier and more often, had higher mean and lower variance for hatching success (number of fry per gram of estimated clutch weight), and suffered fewer stolen fertilizations, nest raids, and territorial encounters than did males nesting outside pots, and in pools without pots (Table 2). Males nesting in pots had the more even temporal distribution of fanning bouts and interfanning intervals; the durations of fanning bouts and interfanning intervals were less variable for these males (Table 2).In replicate aquaria, one male nested on each side of a glass partition and both males spawned approximately simultaneously. Flowerpots were provided to one, both, or neither male. Males with pots had higher mean hatching success, fewer territorial encounters, and the more even temporal distribution of fanning bouts and interfanning intervals (Table 4).Thus it appears that nest site concealment, in the form of clay flowerpots, affected male hatching success, reproductive success, and parental behavior, even when physical contact between males was prevented. These data suggest that a causal relationship may exist between the paternal fanning regime and the subsequent hatching success. Furthermore, these data suggest that males which nest in high concealment increase their reproductive success, and that females which spawn with these males reduce the variance of their hatching success as well as increase their mean hatching success.     

Formation of pi-pi complexes between phenanthrene and model pi-acceptor humic subunits

Pi-pi interactions may play a role in association of aromatic compounds with natural organic substances. Complexation in aqueous solvents was studied between the pi donor, phenanthrene (PHEN), and model pi-acceptor species (quinones and N-heteroaromatic cations) that represent certain functional units of humic substances. Charge-transfer bands in the UV and ring-current shifts in the proton nuclear magnetic resonance (NMR) spectrum confirmed the face-to-face, pi-pi donor-acceptor nature of the bond. Complexation constants were obtained by the solubility enhancement method; solubility enhancements up to 2500 were found. Ruled out as predominant causes of solubility enhancement were monomer desolvation (i.e., "hydrophobic" effects), partitioning into micelles, pi-cation interactions, and pi-hydrogen bonding. Acceptor self-stacking and formation of higher-stoichiometry acceptor-donor complexes had to be considered in evaluating donor-acceptor equilibria in some cases. The affinity of acceptor for PHEN followed the order of increasing pi-acceptor strength and varied strongly with the degree of ring overlap with PHEN. Complexation between PHEN and the free solution faces of an acceptor was less favorable than intercalation of PHEN between two acceptor units in a stack. A positive hydrophobic effect on complexation was evident in water mixtures with acetone or methanol and found to correlate with the number of faces of PHEN requiring desolvation to form the complex. When hydrophobic effects are subtracted out, the pi-pi complex actually becomes favored as the solvent water content and polarity decline. The results suggest that phenanthrene, and by implication other donor aromatic compounds, are capable of forming pi-pi interactions with appropriate humic fragments.     

Solid-state carbon-13 nuclear magnetic resonance of humic acids at high magnetic field strengths

Use of solid-state 13C nuclear magnetic resonance (NMR) spectroscopy has become commonplace in studies of humic substances in soils and sediments, but when modern high-field spectrometers are employed, care must be taken to ensure that the data obtained accurately reflect the chemical composition of these complex materials in environmental systems. In an effort to evaluate the quality of solid-state 13C NMR spectra obtained with modern high-field spectrometers, we conducted a series of experiments to examine spectra of various humic acids taken under a variety of conditions. We evaluate conditions for obtaining semiquantitative cross polarization magic angle spinning (CPMAS) 13C NMR spectra of humic acids at high magnetic field and spinning frequency. We examine the cross polarization (CP) dynamics under both traditional and ramp CP conditions on Cedar Creek humic acid. Fitted equilibrium intensities from these CP dynamic studies compare to within 3.4% of the intensities determined from a Bloch decay spectrum of the same sample. With a 1-ms contact time, ramp CP and traditional CP spectra were acquired on this sample and were found to compare to within 5.4% of the Bloch decay spectrum; however, the signal-to-noise ratio per hour of data acquisition was found to double under ramp CP conditions. These results demonstrate the power of applying modern solid-state NMR techniques at high magnetic field strengths. With these techniques, high-quality, semiquantitative spectra can be quickly produced, allowing the application of solid-state NMR techniques to more environmentally relevant samples, especially those where the quantity is limited.     

The cholesterol lowering property of coriander seeds (Coriandrum sativum): mechanism of action

Coriandrum sativum (Coriander) has been documented as a traditional treatment for cholesterol and diabetes patients. In the present study, coriander seeds incorporated into diet and the effect of the administration of coriander seeds on the metabolism of lipids was studied in rats, fed with high fat diet and added cholesterol. The seeds had a significant hypolipidemic action. In the experimental group of rats (tissue) the level of total cholesterol and triglycerides increased significantly There was significant increase in beta-hydroxy, beta-methyl glutaryl CoA reductase and plasma lecithin cholesterol acyl transferase activity were noted in the experimental group. The level of low density lipoprotein (LDL) + very low density lipoprotein (VLDL) cholesterol decreased while that of high density lipoprotein (HDL) cholesterol increased in the experimental group compared to the control group. The increased activity of plasma LCAT enhanced degradation of cholesterol to fecal bile acids and neutral sterols appeared to account for its hypocholesterolemic effect.     

Potential direct fitness consequences of ornament-based mate choice in a butterfly

Female mate choice has been shown to provide direct mating benefits in several animal groups. In butterflies, for which there are increasing reports of fine-scale color-based mate choice, the evolutionary benefits that accrue from such mating biases, if any, are largely unknown. We addressed this issue in the butterfly Colias eurytheme, a species in which females choose mates on the basis of iridescent ultraviolet (UV) wing ornamentation and in which males donate reproductively beneficial nuptial gifts. In the first experiment, we assessed the mass of gifts donated to 77 virgin females by males sampled directly from a field encounter site. Despite large variance in the male adult phenotype and ejaculate, no single aspect of dorsal wing coloration, including UV brightness, chroma, or hue, was related to ejaculate mass. There was, however, an interesting interaction between the effects of male body size and copula duration upon ejaculate mass, with size scaling positively with ejaculate mass among males involved in shorter copulations (those lasting <70 min) but negatively among males in longer copulations. In the second experiment, we assessed the lifetime fecundity, fertility, and longevity of 85 females mated under similar circumstances to free-flying wild males. Although several wing color parameters proved subtly informative in more sophisticated multivariable models, no model predicted more than about 20% of the variation in any single female fitness parameter. The duration of copulation, which ranged from 35 min to over 16 h and which carries putative costs for females, was, again, only very weakly predicted by male wing color parameters (i.e., R ² = 0.089). Given the overall minor predictive power of male wing coloration in general and of UV brightness in particular, our results do not strongly support the hypothesis that female C. eurytheme prefer bright UV males to obtain direct benefits or to minimize the costs associated with lengthy copulations.     

Displaced honey bees perform optimal scale-free search flights

Honey bees (Apis mellifera) are regularly faced with the task of navigating back to their hives from remote food sources. They have evolved several methods to do this, including compass-directed "vector" flights and the use of landmarks. If these hive-centered mechanisms are disrupted, bees revert to searching for the hive, but the nature and efficiency of their searching strategy have hitherto been unknown. We used harmonic radar to record the flight paths of honey bees that were searching for their hives. Our subsequent analysis of these paths revealed that they can be represented by a series of straight line segments that have a scale-free, Lévy distribution with an inverse-square-law tail. We show that these results, combined with the "no preferred direction" characteristic of the segments, demonstrate that the bees were flying an optimal search pattern. Lévy movements have already been identified in a number of other animals. Our results are the best reported example where the movements are mostly attributable to the adoption of an optimal, scale-free searching strategy.     

Future Trends and Mitigation Options for Energy Consumption and Greenhouse Gas Emissions in a Developing Country of the Middle East Region: a Case Study of Lebanon’s Road Transport Sector

The road transport system in Lebanon is one of the most unsustainable in the Middle East region due to, in large part, the absence of a national transportation strategy. This study proposes mitigation measures based on Lebanon’s commitments for reducing fossil fuel use and CO₂ emissions from road transport by increasing the share of fuel-efficient and hybrid electric vehicles and increasing the utilization of the existing bus service. Results show that increasing the market share of fuel-efficient vehicles to 35% in 2040 stabilizes energy use and emissions. The addition of hybrid vehicles to the first strategy, with a target of 10% market share by 2040, leads to 11% additional savings. Increasing the share of bus passenger kilometers traveled to 45% in 2040 leads to a reversal of adverse impacts. A combined strategy of all three measures leads to 63% reductions in 2040 compared to 2010, which is even superior to their cumulative savings.